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breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Fornasier%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Fornasier%2C+S&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Fornasier%2C+S&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.01409">arXiv:2412.01409</a> <span> [<a href="https://arxiv.org/pdf/2412.01409">pdf</a>, <a href="https://arxiv.org/format/2412.01409">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202451263">10.1051/0004-6361/202451263 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An impact-free mechanism to deliver water to terrestrial planets and exoplanets </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Kral%2C+Q">Quentin Kral</a>, <a href="/search/?searchtype=author&query=Huet%2C+P">Paul Huet</a>, <a href="/search/?searchtype=author&query=Bergez-Casalou%2C+C">Camille Bergez-Casalou</a>, <a href="/search/?searchtype=author&query=Th%C3%A9bault%2C+P">Philippe Th茅bault</a>, <a href="/search/?searchtype=author&query=Charnoz%2C+S">S茅bastien Charnoz</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.01409v1-abstract-short" style="display: inline;"> To date, the most widespread scenario is that the Earth originated without water and was brought to the planet mainly due to impacts by wet asteroids coming from further out in space. However, many uncertainties remain regarding the exact processes that supply water to inner terrestrial planets. This article explores a new mechanism that would allow water to be efficiently transported to planets w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.01409v1-abstract-full').style.display = 'inline'; document.getElementById('2412.01409v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.01409v1-abstract-full" style="display: none;"> To date, the most widespread scenario is that the Earth originated without water and was brought to the planet mainly due to impacts by wet asteroids coming from further out in space. However, many uncertainties remain regarding the exact processes that supply water to inner terrestrial planets. This article explores a new mechanism that would allow water to be efficiently transported to planets without impacts. We propose that primordial asteroids were icy and that when the ice sublimated, it formed a gaseous disk that could then reach planets and deliver water. We have developed a new model that follows the sublimation of asteroids and evolves the subsequent gas disk using a viscous diffusion code. We can then quantify the amount of water that can be accreted onto each planet in a self-consistent manner. We find that this new disk-delivery mechanism can explain the water content on Earth as well as on other planets. Our model shows most of the water being delivered between 20 and 30 Myr after the birth of the Sun. Our scenario implies the presence of a gaseous water disk with substantial mass for 100s Myr, which could be one of the key tracers of this mechanism. We show that such a watery disk could be detected in young exo-asteroid belts with ALMA. We propose that viscous water transport is inevitable and more generic than the impact scenario. We also suggest it is a universal process that may also occur in extrasolar systems. The conditions required for this scenario to unfold are indeed expected to be present in most planetary systems: an opaque proto-planetary disk that is initially cold enough for ice to form in the exo-asteroid belt region, followed by a natural outward-moving snow line that allows this initial ice to sublimate after the dissipation of the primordial disk, creating a viscous secondary gas disk and leading to the accretion of water onto the exoplanets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.01409v1-abstract-full').style.display = 'none'; document.getElementById('2412.01409v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 11 figures, accepted for publication in A&A. Abstract shortened</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.14149">arXiv:2408.14149</a> <span> [<a href="https://arxiv.org/pdf/2408.14149">pdf</a>, <a href="https://arxiv.org/format/2408.14149">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Spectro-photometry of Phobos simulants: II. Effects of porosity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Wargnier%2C+A">Antonin Wargnier</a>, <a href="/search/?searchtype=author&query=Poch%2C+O">Olivier Poch</a>, <a href="/search/?searchtype=author&query=Poggiali%2C+G">Giovanni Poggiali</a>, <a href="/search/?searchtype=author&query=Gautier%2C+T">Thomas Gautier</a>, <a href="/search/?searchtype=author&query=Doressoundiram%2C+A">Alain Doressoundiram</a>, <a href="/search/?searchtype=author&query=Beck%2C+P">Pierre Beck</a>, <a href="/search/?searchtype=author&query=Nakamura%2C+T">Tomoki Nakamura</a>, <a href="/search/?searchtype=author&query=Miyamoto%2C+H">Hideaki Miyamoto</a>, <a href="/search/?searchtype=author&query=Kameda%2C+S">Shingo Kameda</a>, <a href="/search/?searchtype=author&query=Ruscassier%2C+N">Nathalie Ruscassier</a>, <a href="/search/?searchtype=author&query=Buch%2C+A">Arnaud Buch</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">Pedro H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Sultana%2C+R">Robin Sultana</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">Eric Quirico</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Barucci%2C+A">Antonella Barucci</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.14149v1-abstract-short" style="display: inline;"> Surface porosity has been found to be an important property for small bodies. Some asteroids and comets can exhibit an extremely high surface porosity in the first millimeter layer. This layer may be produced by various processes and maintained by the lack of an atmosphere. However, the influence of porosity on the spectro-photometric properties of small body surfaces is not yet fully understood.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14149v1-abstract-full').style.display = 'inline'; document.getElementById('2408.14149v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.14149v1-abstract-full" style="display: none;"> Surface porosity has been found to be an important property for small bodies. Some asteroids and comets can exhibit an extremely high surface porosity in the first millimeter layer. This layer may be produced by various processes and maintained by the lack of an atmosphere. However, the influence of porosity on the spectro-photometric properties of small body surfaces is not yet fully understood. In this study, we looked into the effect of porosity on the spectro-photometric properties of Phobos regolith spectroscopic simulants; created by mixing the simulants with ultra-pure water, producing ice-dust particles, and then sublimating the water. The reflectance spectroscopic properties in the visible and near-infrared (0.5-4.2 $渭$m) show no strong variations between the porous and compact samples. However, one simulant exhibits a bluing of the slope after increasing porosity, providing possible insights into the differences between the blue and red units observed on Phobos. In the mid-infrared range, a contrast increase of the 10-$渭$m emissivity plateau due to silicates is observed. Photometry reveals a modification in the phase reddening behavior between the compact powder and the sublimation residue for both simulants. However, the observed behavior is different between the simulants, suggesting that the phase reddening may be dependent on the composition of the simulants. The phase curve also appears to be modified by the addition of porosity, with a higher contribution of forward scattering observed for the sublimation residue. The derivation of the Hapke parameters indicates an increase in roughness for the porous sample, but no significant modification of the opposition effect. This study aims to provide new insights into the understanding of porosity by using two Phobos simulants in the context of the upcoming JAXA/Martian Moons eXploration mission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14149v1-abstract-full').style.display = 'none'; document.getElementById('2408.14149v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to Icarus</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.13017">arXiv:2407.13017</a> <span> [<a href="https://arxiv.org/pdf/2407.13017">pdf</a>, <a href="https://arxiv.org/format/2407.13017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202450447">10.1051/0004-6361/202450447 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Size, albedo and rotational period of the Hayabusa2# target (98943) 2001 CC21 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Dotto%2C+E">E. Dotto</a>, <a href="/search/?searchtype=author&query=Panuzzo%2C+P">P. Panuzzo</a>, <a href="/search/?searchtype=author&query=Delb%C3%B2%2C+M">M. Delb貌</a>, <a href="/search/?searchtype=author&query=Belskaya%2C+I">I. Belskaya</a>, <a href="/search/?searchtype=author&query=Krugly%2C+Y">Y. Krugly</a>, <a href="/search/?searchtype=author&query=Inasaridze%2C+R">R. Inasaridze</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Perna%2C+D">D. Perna</a>, <a href="/search/?searchtype=author&query=Brucato%2C+J">J. Brucato</a>, <a href="/search/?searchtype=author&query=Birlan%2C+M">M. Birlan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.13017v1-abstract-short" style="display: inline;"> This study aims to determine the size, albedo and rotational period of (98943) 2001 CC21, target of the Hayabusa2 extended mission, using thermal data from the Spitzer Space telescope and ground based observations. The Spitzer data were acquired with the Infrared Spectrograph in the 6-38 micron range, reduced using the Spitzer pipeline and modeled with the Near Earth Asteroid Thermal Modeling to d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13017v1-abstract-full').style.display = 'inline'; document.getElementById('2407.13017v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.13017v1-abstract-full" style="display: none;"> This study aims to determine the size, albedo and rotational period of (98943) 2001 CC21, target of the Hayabusa2 extended mission, using thermal data from the Spitzer Space telescope and ground based observations. The Spitzer data were acquired with the Infrared Spectrograph in the 6-38 micron range, reduced using the Spitzer pipeline and modeled with the Near Earth Asteroid Thermal Modeling to determine the asteroid size and albedo. The absolute magnitude and the rotational period were determined thanks to new observations carried out at the 3.5m New Technology Telescope, at the 1.2m Observatoire de Haute Provence, and at the 0.7m Abastumani telescope. Three complete lightcurves were obtained in 2023-2024 at the last mentioned telescope. We determine an absolute magnitude of H=18.94$\pm$0.05, and a rotational period of 5.02124$\pm$0.00001 hours, with a large lightcurve amplitude of $\sim$ 0.8 mag. at a phase angle of 22$^o$, indicating a very elongated shape with estimated a/b semiaxis ratio $\geq$ 1.7, or a close-contact binary body. The emissivity of 2001 CC21 is consistent with that of silicates, and its albedo is 21.6$\pm$1.6 %. Finally, the spherical-equivalent diameter of 2001 CC21 is 465$\pm$15 m. The albedo value and emissivity here determined, coupled with results from polarimetry and spectroscopy from the literature, confirm that 2001 CC21 is an S-complex asteroid, and not a L-type, as previously suggested. The size of 2001 CC21 is less than 500 m, which is smaller than its first size estimation ($\sim$ 700 m). These results are relevant in preparation of the observing strategy of 2001 CC21 by Hayabusa2 extended mission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13017v1-abstract-full').style.display = 'none'; document.getElementById('2407.13017v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 9 figures, accepted for publication in A&A letter</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 688, L7 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.02999">arXiv:2405.02999</a> <span> [<a href="https://arxiv.org/pdf/2405.02999">pdf</a>, <a href="https://arxiv.org/format/2405.02999">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Spectro-photometry of Phobos simulants: I. Detectability of hydrated minerals and organic bands </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Wargnier%2C+A">Antonin Wargnier</a>, <a href="/search/?searchtype=author&query=Gautier%2C+T">Thomas Gautier</a>, <a href="/search/?searchtype=author&query=Doressoundiram%2C+A">Alain Doressoundiram</a>, <a href="/search/?searchtype=author&query=Poggiali%2C+G">Giovanni Poggiali</a>, <a href="/search/?searchtype=author&query=Beck%2C+P">Pierre Beck</a>, <a href="/search/?searchtype=author&query=Poch%2C+O">Olivier Poch</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">Eric Quirico</a>, <a href="/search/?searchtype=author&query=Nakamura%2C+T">Tomoki Nakamura</a>, <a href="/search/?searchtype=author&query=Miyamoto%2C+H">Hideaki Miyamoto</a>, <a href="/search/?searchtype=author&query=Kameda%2C+S">Shingo Kameda</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">Pedro H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Ruscassier%2C+N">Nathalie Ruscassier</a>, <a href="/search/?searchtype=author&query=Buch%2C+A">Arnaud Buch</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">Maria Antonietta Barucci</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.02999v1-abstract-short" style="display: inline;"> Previous observations of Phobos and Deimos, the moons of Mars, have improved our understanding of these small bodies. However, their formation and composition remain poorly constrained. Physical and spectral properties suggest that Phobos may be a weakly thermal-altered captured asteroid but the dynamical properties of the martian system suggest a formation by giant collision similar to the Earth… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.02999v1-abstract-full').style.display = 'inline'; document.getElementById('2405.02999v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.02999v1-abstract-full" style="display: none;"> Previous observations of Phobos and Deimos, the moons of Mars, have improved our understanding of these small bodies. However, their formation and composition remain poorly constrained. Physical and spectral properties suggest that Phobos may be a weakly thermal-altered captured asteroid but the dynamical properties of the martian system suggest a formation by giant collision similar to the Earth moon. In 2027, the JAXA's MMX mission aims to address these outstanding questions. We undertook measurements with a new simulant called OPPS (Observatory of Paris Phobos Simulant) which closely matches Phobos spectra in the visible to the mid-infrared range. The simulant was synthesized using a mixture of olivine, saponite, anthracite, and coal. Since observation geometry is a crucial aspect of planetary surface remote sensing exploration, we evaluated the parameters obtained by modeling the phase curves -- obtained through laboratory measurements -- of two different Phobos simulants (UTPS-TB and OPPS) using Hapke IMSA model. Our results show that the photometric properties of Phobos simulants are not fully consistent with those of Tagish Lake, Allende, or the NWA 4766 shergottite. We also investigated the detection of volatiles/organic compounds and hydrated minerals, as the presence of such components is expected on Phobos in the hypothesis of a captured primitive asteroid. The results indicate that a significant amount of organic compounds is required for the detection of C-H bands at 3.4 $渭$m. In contrast, the 2.7 $渭$m absorption band, due to hydrated minerals, is much deeper and easier to detect than C-H organic features at the same concentration levels. Posing limits on detectability of some possible key components of Phobos surface will be pivotal to prepare and interpret future observations of the MIRS spectrometer onboard MMX mission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.02999v1-abstract-full').style.display = 'none'; document.getElementById('2405.02999v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">58 pages, 19 figures, submitted to Icarus</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.12156">arXiv:2403.12156</a> <span> [<a href="https://arxiv.org/pdf/2403.12156">pdf</a>, <a href="https://arxiv.org/format/2403.12156">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202449220">10.1051/0004-6361/202449220 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phobos photometric properties from Mars Express HRSC observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Wargnier%2C+A">A. Wargnier</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Tirsch%2C+D">D. Tirsch</a>, <a href="/search/?searchtype=author&query=Matz%2C+K+-">K. -D. Matz</a>, <a href="/search/?searchtype=author&query=Doressoundiram%2C+A">A. Doressoundiram</a>, <a href="/search/?searchtype=author&query=Gautier%2C+T">T. Gautier</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.12156v1-abstract-short" style="display: inline;"> This study aims to analyze Phobos' photometric properties using Mars Express mission observations to support the Martian Moons eXploration mission. We analyzed resolved images of Phobos acquired between 2004 and 2022 by the HRSC and the SRC cameras on board the Mars Express spacecraft. We performed photometric analysis using the Hapke model for both integrated and disk-resolved data. The Phobos ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12156v1-abstract-full').style.display = 'inline'; document.getElementById('2403.12156v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.12156v1-abstract-full" style="display: none;"> This study aims to analyze Phobos' photometric properties using Mars Express mission observations to support the Martian Moons eXploration mission. We analyzed resolved images of Phobos acquired between 2004 and 2022 by the HRSC and the SRC cameras on board the Mars Express spacecraft. We performed photometric analysis using the Hapke model for both integrated and disk-resolved data. The Phobos phase function has a strong opposition effect due to shadow hiding, with an amplitude and a half-width of the opposition surge of 2.28$\pm$0.03 and 0.0573$\pm$0.0001, respectively. Overall, the surface of Phobos is dark, with a geometric albedo of 6.8 % in the green filter and backscattering. We also found a surface porosity of 87\%, indicating the presence of a thick dust mantle or of fractal aggregates on the top surface. The SSA maps revealed high reflectance variability, with the blue unit area in the northeast Stickney rim being up to 65\% brighter than average, while the Stickney floor is among the darkest regions, with reflectance 10 to 20% lower than average. Photometric modeling of the regions of interest selected in the red and blue units indicates that red unit terrains have a stronger opposition effect and a smaller SSA value than the blue ones, but they have similar porosity and backscattering properties. The HRSC data provide a unique investigation of the Phobos phase function and opposition surge, which is valuable information for the MMX observational planning. The Phobos opposition surge, surface porosity, phase integral, and spectral slope are very similar to the values observed for the comet 67P and for Jupiter family comets in general. Based on these similarities, we formulate a hypothesis that the Mars satellites might be the results of a binary or bilobated comet captured by Mars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12156v1-abstract-full').style.display = 'none'; document.getElementById('2403.12156v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 16 figures, accepted for publication in Astron. & Astroph</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 686, A203 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.11424">arXiv:2302.11424</a> <span> [<a href="https://arxiv.org/pdf/2302.11424">pdf</a>, <a href="https://arxiv.org/format/2302.11424">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202245614">10.1051/0004-6361/202245614 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Volatile exposures on the 67P/Churyumov-Gerasimenko nucleus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Hoang%2C+H+V">H. V. Hoang</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">E. Quirico</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">M. Ciarniello</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2302.11424v2-abstract-short" style="display: inline;"> We present the most extensive catalog of exposures of volatiles on the 67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the OSIRIS cameras on board the Rosetta mission. We identified more than 600 volatile exposures on the comet. Bright spots are found isolated on the nucleus or grouped in clusters, usually at the bottom of cliffs, and most of them are small, typically a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.11424v2-abstract-full').style.display = 'inline'; document.getElementById('2302.11424v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.11424v2-abstract-full" style="display: none;"> We present the most extensive catalog of exposures of volatiles on the 67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the OSIRIS cameras on board the Rosetta mission. We identified more than 600 volatile exposures on the comet. Bright spots are found isolated on the nucleus or grouped in clusters, usually at the bottom of cliffs, and most of them are small, typically a few square meters or smaller. Several of them are clearly correlated with the cometary activity. We note a number of peculiar exposures of volatiles with negative spectral slope values in the high-resolution post-perihelion images, which we interpret as the presence of large ice grains ($>$ 1000 $渭$m) or local frosts condensation. We observe a clear difference both in the spectral slope and in the area distributions of the bright spots pre- and post-perihelion, with these last having lower average spectral slope values and a smaller size, with a median surface of 0.7 m$^2$, even if the size difference is mainly due to the higher resolution achieved post-perihelion. The minimum duration of the bright spots shows three clusters: an area-independent cluster dominated by short-lifetime frosts; an area-independent cluster with lifetime of 0.5--2 days, probably associated with the seasonal fallout of dehydrated chunks; and an area-dependent cluster with lifetime longer than 2 days consistent with water-driven erosion of the nucleus. Even if numerous bright spots are detected, the total surface of exposed water ice is less than 0.1% of the total 67P nucleus surface, confirming that the 67P surface is dominated by refractory dark terrains, while exposed ice occupies only a tiny fraction. Moreover, the abundance of volatile exposures is six times less in the small lobe than in the big lobe, adding additional evidence to the hypothesis that comet 67P is composed of two distinct bodies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.11424v2-abstract-full').style.display = 'none'; document.getElementById('2302.11424v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 19 Figures; paper accepted for publication in Astron. and Astrophysics on February 2023</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 672, A136 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.01165">arXiv:2302.01165</a> <span> [<a href="https://arxiv.org/pdf/2302.01165">pdf</a>, <a href="https://arxiv.org/format/2302.01165">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stad330">10.1093/mnras/stad330 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> NEOROCKS project: surface properties of small near-Earth asteroids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hromakina%2C+T">T. Hromakina</a>, <a href="/search/?searchtype=author&query=Birlan%2C+M">M. Birlan</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Fulchignoni%2C+M">M. Fulchignoni</a>, <a href="/search/?searchtype=author&query=Colas%2C+F">F. Colas</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Merlin%2C+F">F. Merlin</a>, <a href="/search/?searchtype=author&query=Sonka%2C+A">A. Sonka</a>, <a href="/search/?searchtype=author&query=Anghel%2C+S">S. Anghel</a>, <a href="/search/?searchtype=author&query=Poggiali%2C+G">G. Poggiali</a>, <a href="/search/?searchtype=author&query=Belskaya%2C+I">I. Belskaya</a>, <a href="/search/?searchtype=author&query=Perna%2C+D">D. Perna</a>, <a href="/search/?searchtype=author&query=Dotto%2C+E">E. Dotto</a>, <a href="/search/?searchtype=author&query=team%2C+t+N">the NEOROCKS team</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2302.01165v1-abstract-short" style="display: inline;"> We present new results of the observing program which is a part of the NEOROCKS project aimed to improve knowledge on physical properties of near-Earth Objects (NEOs) for planetary defense. Photometric observations were performed using the 1.2m telescope at the Haute-Provence observatory (France) in the BVRI filters of the Johnson-Cousins photometric systems between June 2021 and April 2022. We ob… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.01165v1-abstract-full').style.display = 'inline'; document.getElementById('2302.01165v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.01165v1-abstract-full" style="display: none;"> We present new results of the observing program which is a part of the NEOROCKS project aimed to improve knowledge on physical properties of near-Earth Objects (NEOs) for planetary defense. Photometric observations were performed using the 1.2m telescope at the Haute-Provence observatory (France) in the BVRI filters of the Johnson-Cousins photometric systems between June 2021 and April 2022. We obtained new surface colors for 42 NEOs. Based on the measured colors we classified 20 objects as S-complex, 9 as C-complex, 9 as X-complex, 2 as D-type, one object as V-type, and one object remained unclassified. For all the observed objects we estimated their absolute magnitudes and diameters. Combining these new observations with the previously acquired data within the NEOROCKS project extended our dataset to 93 objects. The majority of objects in the dataset with diameters D<500m belongs to a group of silicate bodies, which could be related to observational bias. Based on MOID and $螖$V values we selected 14 objects that could be accessible by a spacecraft. Notably, we find D-type asteroid (163014) 2001 UA5 and A-type asteroid 2017 SE19 to be of particular interest as possible space mission targets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.01165v1-abstract-full').style.display = 'none'; document.getElementById('2302.01165v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.08134">arXiv:2210.08134</a> <span> [<a href="https://arxiv.org/pdf/2210.08134">pdf</a>, <a href="https://arxiv.org/format/2210.08134">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stac2560">10.1093/mnras/stac2560 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CO2-driven surface changes in the Hapi region on Comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Davidsson%2C+B+J+R">Bj枚rn J. R. Davidsson</a>, <a href="/search/?searchtype=author&query=Schloerb%2C+F+P">F. Peter Schloerb</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">Nilda Oklay</a>, <a href="/search/?searchtype=author&query=Guti%C3%A9rrez%2C+P+J">Pedro J. Guti茅rrez</a>, <a href="/search/?searchtype=author&query=Buratti%2C+B+J">Bonnie J. Buratti</a>, <a href="/search/?searchtype=author&query=Chmielewski%2C+A+B">Artur B. Chmielewski</a>, <a href="/search/?searchtype=author&query=Gulkis%2C+S">Samuel Gulkis</a>, <a href="/search/?searchtype=author&query=Hofstadter%2C+M+D">Mark D. Hofstadter</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. Uwe Keller</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">Holger Sierks</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">Carsten G眉ttler</a>, <a href="/search/?searchtype=author&query=K%C3%BCppers%2C+M">Michael K眉ppers</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">Hans Rickman</a>, <a href="/search/?searchtype=author&query=Choukroun%2C+M">Mathieu Choukroun</a>, <a href="/search/?searchtype=author&query=Lee%2C+S">Seungwon Lee</a>, <a href="/search/?searchtype=author&query=Lellouch%2C+E">Emmanuel Lellouch</a>, <a href="/search/?searchtype=author&query=Lethuillier%2C+A">Anthony Lethuillier</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">Vania Da Deppo</a>, <a href="/search/?searchtype=author&query=Groussin%2C+O">Olivier Groussin</a>, <a href="/search/?searchtype=author&query=K%C3%BChrt%2C+E">Ekkehard K眉hrt</a>, <a href="/search/?searchtype=author&query=Thomas%2C+N">Nicolas Thomas</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">Cecilia Tubiana</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. Ramy El-Maarry</a>, <a href="/search/?searchtype=author&query=La+Forgia%2C+F">Fiorangela La Forgia</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.08134v1-abstract-short" style="display: inline;"> Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a 140m wide and 0.5m deep depression in the Hapi region on Comet 67P/Churyumov-Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles. We have compiled observations of this region in Hap… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.08134v1-abstract-full').style.display = 'inline'; document.getElementById('2210.08134v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.08134v1-abstract-full" style="display: none;"> Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a 140m wide and 0.5m deep depression in the Hapi region on Comet 67P/Churyumov-Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles. We have compiled observations of this region in Hapi by the microwave instrument MIRO on Rosetta, acquired during October and November 2014. We use thermophysical and radiative transfer models in order to reproduce the MIRO observations. This allows us to place constraints on the thermal inertia, diffusivity, chemical composition, stratification, extinction coefficients, and scattering properties of the surface material, and how they evolved during the months prior to pit formation. The results are placed in context through long-term comet nucleus evolution modelling. We propose that: 1) MIRO observes signatures that are consistent with a solid-state greenhouse effect in airfall material; 2) CO2 ice is sufficiently close to the surface to have a measurable effect on MIRO antenna temperatures, and likely is responsible for the pit formation in Hapi observed by OSIRIS; 3) the pressure at the CO2 sublimation front is sufficiently strong to expel dust and water ice outwards, and to compress comet material inwards, thereby causing the near-surface compaction observed by CONSERT, SESAME, and groundbased radar, manifested as the "consolidated terrain" texture observed by OSIRIS. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.08134v1-abstract-full').style.display = 'none'; document.getElementById('2210.08134v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages, 41 figures. This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer review</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mon. Not. R. Astron. Soc. 516, 6009-6040 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.02741">arXiv:2210.02741</a> <span> [<a href="https://arxiv.org/pdf/2210.02741">pdf</a>, <a href="https://arxiv.org/format/2210.02741">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Comet nuclei composition and evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Filacchione%2C+G">Gianrico Filacchione</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">Mauro Ciarniello</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Raponi%2C+A">Andrea Raponi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.02741v1-abstract-short" style="display: inline;"> Thanks to Rosetta orbiter's and Philae lander's data our knowledge of cometary nuclei composition has experienced a great advancement. The properties of 67P/CG nucleus are discussed and compared with other comets explored in the past by space missions. Cometary nuclei are made by a collection of ices, minerals, organic matter, and salts resulting in very dark and red-colored surfaces. When far fro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02741v1-abstract-full').style.display = 'inline'; document.getElementById('2210.02741v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.02741v1-abstract-full" style="display: none;"> Thanks to Rosetta orbiter's and Philae lander's data our knowledge of cometary nuclei composition has experienced a great advancement. The properties of 67P/CG nucleus are discussed and compared with other comets explored in the past by space missions. Cometary nuclei are made by a collection of ices, minerals, organic matter, and salts resulting in very dark and red-colored surfaces. When far from the Sun, exposed water and carbon dioxide ices are found only in few locations of 67P/CG where the exposure of pristine subsurface layers or the recondensation of volatile species driven by the solar heating and local terrain morphology can sustain their temporary presence on the surface. The nucleus surface appears covered by a dust layer of variable thickness. Dust grains appear mostly dehydrated and are made by an assemblage of minerals, organic matter, and salts. Spectral analysis shows that the mineral phase is dominated by silicates, fine-grained opaques and ammoniated salts. Aliphatic and aromatic groups, with the presence of the strong hydroxyl group, are identified within the organic matter. The surface composition of cometary nuclei evolves with heliocentric distance and seasonal cycling: approaching perihelion the increase of the solar flux boosts the activity through the sublimation of volatiles which in turn causes the erosion of surface layers, the exposure of ices, the activity in cliffs and pits, the collapse of overhangs and walls, and the mobilization and redistribution of dust. The evolution of color, composition, and texture changes occurring across different morphological regions of the nucleus are correlated with these processes. In this chapter we discuss 67P/CG nucleus composition and evolutionary processes as observed by Rosetta mission in the context of other comets previously explored by space missions or observed from Earth. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02741v1-abstract-full').style.display = 'none'; document.getElementById('2210.02741v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">46 page, 34 figures, 4 tables, Chapter in press for the book Comets III, edited by K. Meech and M. Combi, University of Arizona Press</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.11672">arXiv:2206.11672</a> <span> [<a href="https://arxiv.org/pdf/2206.11672">pdf</a>, <a href="https://arxiv.org/ps/2206.11672">ps</a>, <a href="https://arxiv.org/format/2206.11672">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202243816">10.1051/0004-6361/202243816 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing the surface environment of large T-type asteroids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Kwon%2C+Y+G">Yuna G. Kwon</a>, <a href="/search/?searchtype=author&query=Hasegawa%2C+S">Sunao Hasegawa</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Ishiguro%2C+M">Masateru Ishiguro</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">Jessica Agarwal</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.11672v1-abstract-short" style="display: inline;"> We probed the surface environment of large ($>$80 km in diameter) T-type asteroids, a taxonomic type relatively ill-constrained as an independent group, and discussed their place of origin. We performed spectroscopic observations of two T-type asteroids, (96) Aegle and (570) Kythera, over 2.8--4.0 $渭$m using the Subaru telescope. With other T-types' spectra available in the literature and survey d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.11672v1-abstract-full').style.display = 'inline'; document.getElementById('2206.11672v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.11672v1-abstract-full" style="display: none;"> We probed the surface environment of large ($>$80 km in diameter) T-type asteroids, a taxonomic type relatively ill-constrained as an independent group, and discussed their place of origin. We performed spectroscopic observations of two T-type asteroids, (96) Aegle and (570) Kythera, over 2.8--4.0 $渭$m using the Subaru telescope. With other T-types' spectra available in the literature and survey datasets, we strove to find commonalities and global trends in this group. We also utilised the asteroids' polarimetric data and meteorite spectra to constrain their surface texture and composition. Our targets exhibit red $L$-band continuum slopes similar to (1) Ceres and 67P/Churyumov-Gerasimenko, and have an OH-absorption feature with band centres $<$2.8 $渭$m. (96) Aegle hints at a shallow N--H band near 3.1 $渭$m and C--H band of organic materials over 3.4--3.6 $渭$m, whereas no diagnostic bands of water ice and other volatiles exceeding the noise of the data were seen for both asteroids. The large T-type asteroids but (596) Scheila display similar spectral shapes to our targets. $\sim$50 \% of large T-types contain an absorption band near 0.6--0.65 $渭$m likely associated with hydrated minerals. For T-type asteroids (except Jupiter Trojans) of all sizes, we found a weak correlation: the smaller the diameter and the closer the Sun, the redder the visible slope. The 2.9-$渭$m band depths of large T-types suggest that they might have experienced aqueous alteration comparable to Ch-types but more intense than most of the main-belt asteroids. The polarimetric phase curve of the T-types is well described by a particular surface structure and their 0.5--4.0 $渭$m reflectance spectra appear most similar to CI chondrites with grain sizes of $\sim$25--35 $渭$m. Taken as a whole, we propose that large T-type asteroids might be dislodged roughly around 10 au in the early solar system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.11672v1-abstract-full').style.display = 'none'; document.getElementById('2206.11672v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 666, A173 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.00978">arXiv:2107.00978</a> <span> [<a href="https://arxiv.org/pdf/2107.00978">pdf</a>, <a href="https://arxiv.org/format/2107.00978">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202141014">10.1051/0004-6361/202141014 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Small lobe of comet 67P: Characterization of the Wosret region with ROSETTA-OSIRIS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=de+Micas%2C+J+B">Jules Bourdelle de Micas</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">Pedro H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Hoang%2C+V+H">Van H. Hoang</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">Maria Antonietta Barucci</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">Holger Sierks</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.00978v1-abstract-short" style="display: inline;"> We investigated Wosret, a region located on the small lobe of the 67P/Churyumov-Gerasimenko comet subject to strong heating during the perihelion passage. This region includes Abydos, the final landing site of the Philae lander. We analyzed high-resolution images of the Wosret region acquired between 2015 and 2016 by the OSIRIS instrument on board the Rosetta spacecraft. We observed a few morpholo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.00978v1-abstract-full').style.display = 'inline'; document.getElementById('2107.00978v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.00978v1-abstract-full" style="display: none;"> We investigated Wosret, a region located on the small lobe of the 67P/Churyumov-Gerasimenko comet subject to strong heating during the perihelion passage. This region includes Abydos, the final landing site of the Philae lander. We analyzed high-resolution images of the Wosret region acquired between 2015 and 2016 by the OSIRIS instrument on board the Rosetta spacecraft. We observed a few morphological changes in Wosret, related to local dust coating removal with an estimated depth of $\sim$ 1 m, along with the formation of a cavity measuring 30 m in length and 6.5 m in depth, for a total estimated mass loss of 1.2 $\times$ 10$^6$ kg. The spectrophotometry of the region is typical of medium-red regions of comet 67P, with spectral slope values of 15-16 \%/(100 nm) in pre-perihelion data acquired at phase angle 60$^o$. Wosret has a spectral phase reddening of 0.0546 $\times 10^{-4}$ nm$^{-1} deg^{-1}$, which is about a factor of 2 lower than what was determined for the nucleus northern hemisphere regions, possibly indicating a reduced surface micro-roughness due to the lack of widespread dust coating. A few tiny bright spots are observed. Morphological features such as "goosebumps" or clods are widely present and larger in size than similar features located in the big lobe. Compared to Anhur and Khonsu, two southern hemisphere regions in the big lobe which are also exposed to high insolation during perihelion, Wosret exhibits fewer exposed volatiles and less morphological variations due to activity events. Our analysis indicates that the small lobe has different physical and mechanical properties than the big one and a lower volatile content, at least in its uppermost layers. These results support the hypothesis that comet 67P originated from the merging of two distinct bodies in the early Solar System. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.00978v1-abstract-full').style.display = 'none'; document.getElementById('2107.00978v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 12 figures, accepted for publication in Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 653, A132 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.09339">arXiv:2011.09339</a> <span> [<a href="https://arxiv.org/pdf/2011.09339">pdf</a>, <a href="https://arxiv.org/format/2011.09339">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202039552">10.1051/0004-6361/202039552 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase reddening on asteroid Bennu from visible and near-infrared spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">J. D. P Deshapriya</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Clark%2C+B+E">B. E. Clark</a>, <a href="/search/?searchtype=author&query=Praet%2C+A">A. Praet</a>, <a href="/search/?searchtype=author&query=Hamilton%2C+V+E">V. E. Hamilton</a>, <a href="/search/?searchtype=author&query=Simon%2C+A">A. Simon</a>, <a href="/search/?searchtype=author&query=Li%2C+J">J-Y. Li</a>, <a href="/search/?searchtype=author&query=Cloutis%2C+E+A">E. A. Cloutis</a>, <a href="/search/?searchtype=author&query=Merlin%2C+F">F. Merlin</a>, <a href="/search/?searchtype=author&query=Zou%2C+X">X-D. Zou</a>, <a href="/search/?searchtype=author&query=Lauretta%2C+D+S">D. S. Lauretta</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.09339v1-abstract-short" style="display: inline;"> The NASA mission OSIRIS-REx has been observing near-Earth asteroid (101955) Bennu in close proximity since December 2018. In this work, we investigate spectral phase reddening -- that is, the variation of spectral slope with phase angle -- on Bennu using spectra acquired by the OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS) covering a phase angle range of 8-130$^{o}$. We investigate this pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09339v1-abstract-full').style.display = 'inline'; document.getElementById('2011.09339v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.09339v1-abstract-full" style="display: none;"> The NASA mission OSIRIS-REx has been observing near-Earth asteroid (101955) Bennu in close proximity since December 2018. In this work, we investigate spectral phase reddening -- that is, the variation of spectral slope with phase angle -- on Bennu using spectra acquired by the OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS) covering a phase angle range of 8-130$^{o}$. We investigate this process at the global scale and for some localized regions of interest (ROIs), including boulders, craters, and the designated sample collection sites of the OSIRIS-REx mission. Bennu has a globally negative spectra slope, which is typical of B-type asteroids. The spectral slope gently increases in a linear way up to a phase angle of 90$^{\circ}$, where it approaches zero. The spectral phase reddening is monotonic and wavelength-dependent with highest values in the visible range. Its coefficient is 0.00044 $渭$m$^{-1} ~deg^{-1}$ in the 0.55-2.5 $渭$m range. For observations of Bennu acquired at high phase angle (130$^{\circ}$), phase reddening increases exponentially. Similar behavior was reported in the literature for the carbonaceous chondrite Mukundpura in spectra acquired at extreme geometries. Some ROIs, including the sample collection site, Nightingale, have a steeper phase reddening coefficient than the global average, potentially indicating a surface covered by fine material with high micro-roughness. The gentle spectral phase reddening effect on Bennu is similar to that observed in ground-based measurements of other B-type asteroids, but much lower than that observed for other low-albedo bodies such as Ceres or comet 67P/Churyumov-Gerasimenko. Monotonic reddening may be associated with the presence of fine particles at micron scales and/or of particles with fractal structure that introduce micro- and sub-micro roughness across the surface of Bennu. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09339v1-abstract-full').style.display = 'none'; document.getElementById('2011.09339v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 12 figures, Astron. and Astroph., in press</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 644, A142 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.04032">arXiv:2010.04032</a> <span> [<a href="https://arxiv.org/pdf/2010.04032">pdf</a>, <a href="https://arxiv.org/format/2010.04032">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.icarus.2020.114106">10.1016/j.icarus.2020.114106 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modeling optical roughness and first-order scattering processes from OSIRIS-REx color images of the rough surface of asteroid (101955) Bennu </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">Pedro H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">Maria A. Barucci</a>, <a href="/search/?searchtype=author&query=Praet%2C+A">Alice Praet</a>, <a href="/search/?searchtype=author&query=Clark%2C+B+E">Beth E. Clark</a>, <a href="/search/?searchtype=author&query=Li%2C+J">Jian-Yang Li</a>, <a href="/search/?searchtype=author&query=Golish%2C+D+R">Dathon R. Golish</a>, <a href="/search/?searchtype=author&query=DellaGiustina%2C+D+N">Daniella N. DellaGiustina</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">Jasinghege Don P. Deshapriya</a>, <a href="/search/?searchtype=author&query=Zou%2C+X">Xian-Duan Zou</a>, <a href="/search/?searchtype=author&query=Daly%2C+M+G">Mike G. Daly</a>, <a href="/search/?searchtype=author&query=Barnouin%2C+O+S">Olivier S. Barnouin</a>, <a href="/search/?searchtype=author&query=Simon%2C+A+A">Amy A. Simon</a>, <a href="/search/?searchtype=author&query=Lauretta%2C+D+S">Dante S. Lauretta</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.04032v1-abstract-short" style="display: inline;"> The dark asteroid (101955) Bennu studied by NASA\textquoteright s OSIRIS-REx mission has a boulder-rich and apparently dust-poor surface, providing a natural laboratory to investigate the role of single-scattering processes in rough particulate media. Our goal is to define optical roughness and other scattering parameters that may be useful for the laboratory preparation of sample analogs, interpr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.04032v1-abstract-full').style.display = 'inline'; document.getElementById('2010.04032v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.04032v1-abstract-full" style="display: none;"> The dark asteroid (101955) Bennu studied by NASA\textquoteright s OSIRIS-REx mission has a boulder-rich and apparently dust-poor surface, providing a natural laboratory to investigate the role of single-scattering processes in rough particulate media. Our goal is to define optical roughness and other scattering parameters that may be useful for the laboratory preparation of sample analogs, interpretation of imaging data, and analysis of the sample that will be returned to Earth. We rely on a semi-numerical statistical model aided by digital terrain model (DTM) shadow ray-tracing to obtain scattering parameters at the smallest surface element allowed by the DTM (facets of \textasciitilde{}10 cm). Using a Markov Chain Monte Carlo technique, we solved the inversion problem on all four-band images of the OSIRIS-REx mission\textquoteright s top four candidate sample sites, for which high-precision laser altimetry DTMs are available. We reconstructed the \emph{a posteriori} probability distribution for each parameter and distinguished primary and secondary solutions. Through the photometric image correction, we found that a mixing of low and average roughness slope best describes Bennu's surface for up to $90^{\circ}$ phase angle. We detected a low non-zero specular ratio, perhaps indicating exposed sub-centimeter mono-crystalline inclusions on the surface. We report an average roughness RMS slope of $27_{-5}^{\circ+1}$, a specular ratio of $2.6_{-0.8}^{+0.1}\%$, an approx. single-scattering albedo of $4.64_{-0.09}^{+0.08}\%$ at 550 nm, and two solutions for the back-scatter asymmetric factor, $尉^{(1)}=-0.360\pm0.030$ and $尉^{(2)}=-0.444\pm0.020$, for all four sites altogether. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.04032v1-abstract-full').style.display = 'none'; document.getElementById('2010.04032v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Icarus 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.14476">arXiv:2009.14476</a> <span> [<a href="https://arxiv.org/pdf/2009.14476">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-019-0992-8">10.1038/s41550-019-0992-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Infrared detection of aliphatic organics on a cometary nucleus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Raponi%2C+A">A. Raponi</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">M. Ciarniello</a>, <a href="/search/?searchtype=author&query=Capaccioni%2C+F">F. Capaccioni</a>, <a href="/search/?searchtype=author&query=Mennella%2C+V">V. Mennella</a>, <a href="/search/?searchtype=author&query=Filacchione%2C+G">G. Filacchione</a>, <a href="/search/?searchtype=author&query=Vinogradoff%2C+V">V. Vinogradoff</a>, <a href="/search/?searchtype=author&query=Poch%2C+O">O. Poch</a>, <a href="/search/?searchtype=author&query=Beck%2C+P">P. Beck</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">E. Quirico</a>, <a href="/search/?searchtype=author&query=De+Sanctis%2C+M+C">M. C. De Sanctis</a>, <a href="/search/?searchtype=author&query=Moroz%2C+L">L. Moroz</a>, <a href="/search/?searchtype=author&query=Kappel%2C+D">D. Kappel</a>, <a href="/search/?searchtype=author&query=Erard%2C+S">S. Erard</a>, <a href="/search/?searchtype=author&query=Bockel%C3%A9e-Morvan%2C+D">D. Bockel茅e-Morvan</a>, <a href="/search/?searchtype=author&query=Longobardo%2C+A">A. Longobardo</a>, <a href="/search/?searchtype=author&query=Tosi%2C+F">F. Tosi</a>, <a href="/search/?searchtype=author&query=Palomba%2C+E">E. Palomba</a>, <a href="/search/?searchtype=author&query=Combe%2C+J+-">J. -P. Combe</a>, <a href="/search/?searchtype=author&query=Rousseau%2C+B">B. Rousseau</a>, <a href="/search/?searchtype=author&query=Arnold%2C+G">G. Arnold</a>, <a href="/search/?searchtype=author&query=Carlson%2C+R+W">R. W. Carlson</a>, <a href="/search/?searchtype=author&query=Pommerol%2C+A">A. Pommerol</a>, <a href="/search/?searchtype=author&query=Pilorget%2C+C">C. Pilorget</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Bellucci%2C+G">G. Bellucci</a> , et al. (6 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.14476v1-abstract-short" style="display: inline;"> The ESA Rosetta mission has acquired unprecedented measurements of comet 67/P-Churyumov-Gerasimenko (hereafter 67P) nucleus surface, whose composition, as determined by in situ and remote sensing instruments including VIRTIS (Visible, InfraRed and Thermal Imaging Spectrometer) appears to be made by an assemblage of ices, minerals, and organic material. We performed a refined analysis of infrared o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14476v1-abstract-full').style.display = 'inline'; document.getElementById('2009.14476v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.14476v1-abstract-full" style="display: none;"> The ESA Rosetta mission has acquired unprecedented measurements of comet 67/P-Churyumov-Gerasimenko (hereafter 67P) nucleus surface, whose composition, as determined by in situ and remote sensing instruments including VIRTIS (Visible, InfraRed and Thermal Imaging Spectrometer) appears to be made by an assemblage of ices, minerals, and organic material. We performed a refined analysis of infrared observations of the nucleus of comet 67P carried out by the VIRTIS-M hyperspectral imager. We found that the overall shape of the 67P infrared spectrum is similar to that of other carbon-rich outer solar system objects suggesting a possible genetic link with them. More importantly, we are also able to confirm the complex spectral structure of the wide 2.8-3.6 micron absorption feature populated by fainter bands. Among these, we unambiguously identified the presence of aliphatic organics by their ubiquitous 3.38, 3.42 and 3.47 micron bands. This novel infrared detection of aliphatic species on a cometary surface has strong implications for the evolutionary history of the primordial solar system and give evidence that comets provide an evolutionary link between interstellar material and solar system bodies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14476v1-abstract-full').style.display = 'none'; document.getElementById('2009.14476v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.03180">arXiv:2008.03180</a> <span> [<a href="https://arxiv.org/pdf/2008.03180">pdf</a>, <a href="https://arxiv.org/format/2008.03180">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> </div> <p class="title is-5 mathjax"> Spectrophotometric characterization of the Philae landing site and surroundings with the ROSETTA/OSIRIS cameras </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Van+Hoang%2C+H">Hong Van Hoang</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">E. Quirico</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2008.03180v1-abstract-short" style="display: inline;"> We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov-Gerasimenko on 12 November 2014. Over 1000 OSIRIS level 3B images were analysed, which cover the August 2014 to September 2016 timeframe, with spatial resolution ranging from 7.6 m/px to approximately 0.06 m/px. We found that the Abydos site is as dark as… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.03180v1-abstract-full').style.display = 'inline'; document.getElementById('2008.03180v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.03180v1-abstract-full" style="display: none;"> We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov-Gerasimenko on 12 November 2014. Over 1000 OSIRIS level 3B images were analysed, which cover the August 2014 to September 2016 timeframe, with spatial resolution ranging from 7.6 m/px to approximately 0.06 m/px. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5% at 649 nm and a spectral slope value of about 17%/(100 nm) at 50$^\circ$ phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass loss of 4.7-7.0$\times$10$^5$ kg. Small spots ranging from 0.1 m$^2$ to 27 m$^2$ were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30-40% locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about one hour. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.03180v1-abstract-full').style.display = 'none'; document.getElementById('2008.03180v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.07158">arXiv:1905.07158</a> <span> [<a href="https://arxiv.org/pdf/1905.07158">pdf</a>, <a href="https://arxiv.org/format/1905.07158">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/B978-0-12-816490-7.00007-2">10.1016/B978-0-12-816490-7.00007-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Trans-Neptunian objects and Centaurs at thermal wavelengths </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=M%C3%BCller%2C+T">Thomas M眉ller</a>, <a href="/search/?searchtype=author&query=Lellouch%2C+E">Emmanuel Lellouch</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.07158v1-abstract-short" style="display: inline;"> The thermal emission of transneptunian objects (TNO) and Centaurs has been observed at mid- and far-infrared wavelengths - with the biggest contributions coming from the Spitzer and Herschel space observatories-, and the brightest ones also at sub-millimeter and millimeter wavelengths. These measurements allowed to determine the sizes and albedos for almost 180 objects, and densities for about 25… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.07158v1-abstract-full').style.display = 'inline'; document.getElementById('1905.07158v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.07158v1-abstract-full" style="display: none;"> The thermal emission of transneptunian objects (TNO) and Centaurs has been observed at mid- and far-infrared wavelengths - with the biggest contributions coming from the Spitzer and Herschel space observatories-, and the brightest ones also at sub-millimeter and millimeter wavelengths. These measurements allowed to determine the sizes and albedos for almost 180 objects, and densities for about 25 multiple systems. The derived very low thermal inertias show evidence for a decrease at large heliocentric distances and for high-albedo objects, which indicates porous and low-conductivity surfaces. The radio emissivity was found to be low ($蔚_r$=0.70$\pm$0.13) with possible spectral variations in a few cases. The general increase of density with object size points to different formation locations or times. The mean albedos increase from about 5-6% (Centaurs, Scattered-Disk Objects) to 15% for the Detached objects, with distinct cumulative albedo distributions for hot and cold classicals. The color-albedo separation in our sample is evidence for a compositional discontinuity in the young Solar System. The median albedo of the sample (excluding dwarf planets and the Haumea family) is 0.08, the albedo of Haumea family members is close to 0.5, best explained by the presence of water ice. The existing thermal measurements remain a treasure trove at times where the far-infrared regime is observationally not accessible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.07158v1-abstract-full').style.display = 'none'; document.getElementById('1905.07158v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Review chapter in "The Trans-Neptunian Solar System" (D. Prialnik, M.A. Barucci and L. Young, eds.), accepted for publication in January 2019, 3 Tables, 2 Figures, 27 Pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.03022">arXiv:1905.03022</a> <span> [<a href="https://arxiv.org/pdf/1905.03022">pdf</a>, <a href="https://arxiv.org/format/1905.03022">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201834869">10.1051/0004-6361/201834869 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=Rinaldi%2C+G">G. Rinaldi</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a>, <a href="/search/?searchtype=author&query=Snodgrass%2C+C">C. Snodgrass</a>, <a href="/search/?searchtype=author&query=Shi%2C+X">X. Shi</a>, <a href="/search/?searchtype=author&query=Hu%2C+X">X. Hu</a>, <a href="/search/?searchtype=author&query=Marschall%2C+R">R. Marschall</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Bockel%C3%A9e-Morvan%2C+D">D. Bockel茅e-Morvan</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/?searchtype=author&query=Capaccioni%2C+F">F. Capaccioni</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Arnold%2C+G">G. Arnold</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Capria%2C+M+T">M. T. Capria</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">M. Ciarniello</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Crovisier%2C+J">J. Crovisier</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a> , et al. (31 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.03022v1-abstract-short" style="display: inline;"> On 27 Apr 2015, when 67P/C-G was at 1.76 au from the Sun and moving towards perihelion, the OSIRIS and VIRTIS-M instruments on Rosetta observed the evolving dust and gas coma during a complete rotation of the comet. We aim to characterize the dust, H2O and CO2 gas spatial distribution in the inner coma. To do this we performed a quantitative analysis of the release of dust and gas and compared the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.03022v1-abstract-full').style.display = 'inline'; document.getElementById('1905.03022v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.03022v1-abstract-full" style="display: none;"> On 27 Apr 2015, when 67P/C-G was at 1.76 au from the Sun and moving towards perihelion, the OSIRIS and VIRTIS-M instruments on Rosetta observed the evolving dust and gas coma during a complete rotation of the comet. We aim to characterize the dust, H2O and CO2 gas spatial distribution in the inner coma. To do this we performed a quantitative analysis of the release of dust and gas and compared the observed H2O production rate with the one calculated using a thermo-physical model. For this study we selected OSIRIS WAC images at 612 nm (dust) and VIRTIS-M image cubes at 612 nm, 2700 nm (H2O) and 4200 nm (CO2). We measured the average signal in a circular annulus, to study spatial variation around the comet, and in a sector of the annulus, to study temporal variation in the sunward direction with comet rotation, both at a fixed distance of 3.1 km from the comet centre. The spatial correlation between dust and water, both coming from the sun-lit side of the comet, shows that water is the main driver of dust activity in this time period. The spatial distribution of CO2 is not correlated with water and dust. There is no strong temporal correlation between the dust brightness and water production rate as the comet rotates. The dust brightness shows a peak at 0deg sub-solar longitude, which is not pronounced in the water production. At the same epoch, there is also a maximum in CO2 production. An excess of measured water production, with respect to the value calculated using a simple thermo-physical model, is observed when the head lobe and regions of the Southern hemisphere with strong seasonal variations are illuminated. A drastic decrease in dust production, when the water production (both measured and from the model) displays a maximum, happens when typical Northern consolidated regions are illuminated and the Southern hemisphere regions with strong seasonal variations are instead in shadow. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.03022v1-abstract-full').style.display = 'none'; document.getElementById('1905.03022v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.06333">arXiv:1904.06333</a> <span> [<a href="https://arxiv.org/pdf/1904.06333">pdf</a>, <a href="https://arxiv.org/ps/1904.06333">ps</a>, <a href="https://arxiv.org/format/1904.06333">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201732564">10.1051/0004-6361/201732564 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> "TNOs are Cool": A survey of the trans-Neptunian region XIV. Size/albedo characterization of the Haumea family observed with Herschel and Spitzer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Vilenius%2C+E">E. Vilenius</a>, <a href="/search/?searchtype=author&query=Stansberry%2C+J">J. Stansberry</a>, <a href="/search/?searchtype=author&query=M%C3%BCller%2C+T">T. M眉ller</a>, <a href="/search/?searchtype=author&query=Mueller%2C+M">M. Mueller</a>, <a href="/search/?searchtype=author&query=Kiss%2C+C">C. Kiss</a>, <a href="/search/?searchtype=author&query=Santos-Sanz%2C+P">P. Santos-Sanz</a>, <a href="/search/?searchtype=author&query=Mommert%2C+M">M. Mommert</a>, <a href="/search/?searchtype=author&query=P%C3%A1l%2C+A">A. P谩l</a>, <a href="/search/?searchtype=author&query=Lellouch%2C+E">E. Lellouch</a>, <a href="/search/?searchtype=author&query=Ortiz%2C+J+L">J. L. Ortiz</a>, <a href="/search/?searchtype=author&query=Peixinho%2C+N">N. Peixinho</a>, <a href="/search/?searchtype=author&query=Thirouin%2C+A">A. Thirouin</a>, <a href="/search/?searchtype=author&query=Lykawka%2C+P+S">P. S. Lykawka</a>, <a href="/search/?searchtype=author&query=Horner%2C+J">J. Horner</a>, <a href="/search/?searchtype=author&query=Duffard%2C+R">R. Duffard</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Delsanti%2C+A">A. Delsanti</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1904.06333v1-abstract-short" style="display: inline;"> A group of trans-Neptunian objects (TNO) are dynamically related to the dwarf planet 136108 Haumea. Ten of them show strong indications of water ice on their surfaces, are assumed to have resulted from a collision, and are accepted as the only known TNO collisional family. Nineteen other dynamically similar objects lack water ice absorptions and are hypothesized to be dynamical interlopers. We hav… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.06333v1-abstract-full').style.display = 'inline'; document.getElementById('1904.06333v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.06333v1-abstract-full" style="display: none;"> A group of trans-Neptunian objects (TNO) are dynamically related to the dwarf planet 136108 Haumea. Ten of them show strong indications of water ice on their surfaces, are assumed to have resulted from a collision, and are accepted as the only known TNO collisional family. Nineteen other dynamically similar objects lack water ice absorptions and are hypothesized to be dynamical interlopers. We have made observations to determine sizes and geometric albedos of six of the accepted Haumea family members and one dynamical interloper. Ten other dynamical interlopers have been measured by previous works. We compare the individual and statistical properties of the family members and interlopers, examining the size and albedo distributions of both groups. We also examine implications for the total mass of the family and their ejection velocities. We use far-infrared space-based telescopes to observe the target TNOs near their thermal peak and combine these data with optical magnitudes to derive sizes and albedos using radiometric techniques. We determine the power-law slope of ejection velocity as a function of effective diameter. The detected Haumea family members have a diversity of geometric albedos $\sim$ 0.3-0.8, which are higher than geometric albedos of dynamically similar objects without water ice. The median geometric albedo for accepted family members is $p_V=0.48_{-0.18}^{+0.28}$, compared to 0.08$_{-0.05}^{+0.07}$ for the dynamical interlopers. In the size range $D=175-300$ km, the slope of the cumulative size distribution is $q$=3.2$_{-0.4}^{+0.7}$ for accepted family members, steeper than the $q$=2.0$\pm$0.6 slope for the dynamical interlopers with D$< $500 km. The total mass of Haumea's moons and family members is 2.4% of Haumea's mass. The ejection velocities required to emplace them on their current orbits show a dependence on diameter, with a power-law slope of 0.21-0.50. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.06333v1-abstract-full').style.display = 'none'; document.getElementById('1904.06333v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astronomy and Astrophysics, Vol. 618, 2018, A136 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.09017">arXiv:1903.09017</a> <span> [<a href="https://arxiv.org/pdf/1903.09017">pdf</a>, <a href="https://arxiv.org/format/1903.09017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201834824">10.1051/0004-6361/201834824 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Surface evolution of the Anhur region on comet 67P from high-resolution OSIRIS images </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Sunshine%2C+J">J. Sunshine</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Shi%2C+X">X. Shi</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Ferrari%2C+S">S. Ferrari</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Gutierrez%2C+P+J">P. J. Gutierrez</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a> , et al. (12 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1903.09017v1-abstract-short" style="display: inline;"> The southern hemisphere of comet 67P/Churyumov-Gerasimenko (67P) became observable by the Rosetta mission in March 2015, a few months before cometary southern vernal equinox. The Anhur region in the southern part of the comet's larger lobe was found to be highly eroded, enriched in volatiles, and highly active. We analyze high-resolution images of the Anhur region pre- and post-perihelion acquired… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.09017v1-abstract-full').style.display = 'inline'; document.getElementById('1903.09017v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.09017v1-abstract-full" style="display: none;"> The southern hemisphere of comet 67P/Churyumov-Gerasimenko (67P) became observable by the Rosetta mission in March 2015, a few months before cometary southern vernal equinox. The Anhur region in the southern part of the comet's larger lobe was found to be highly eroded, enriched in volatiles, and highly active. We analyze high-resolution images of the Anhur region pre- and post-perihelion acquired by the OSIRIS imaging system on board the Rosetta mission. The Narrow Angle Camera is particularly useful for studying the evolution in Anhur in terms of morphological changes and color variations.}{Radiance factor images processed by the OSIRIS pipeline were coregistered, reprojected onto the 3D shape model of the comet, and corrected for the illumination conditions. We find a number of morphological changes in the Anhur region that are related to formation of new scarps; removal of dust coatings; localized resurfacing in some areas, including boulders displacements; and vanishing structures, which implies localized mass loss that we estimate to be higher than 50 million kg. The strongest changes took place in and nearby the Anhur canyon-like structure, where significant dust cover was removed, an entire structure vanished, and many boulders were rearranged. All such changes are potentially associated with one of the most intense outbursts registered by Rosetta during its observations, which occurred one day before perihelion passage. Moreover, in the niche at the foot of a new observed scarp, we also see evidence of water ice exposure that persisted for at least six months. The abundance of water ice, evaluated from a linear mixing model, is relatively high (> 20%). Our results confirm that the Anhur region is volatile-rich and probably is the area on 67P with the most pristine exposures near perihelion. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.09017v1-abstract-full').style.display = 'none'; document.getElementById('1903.09017v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 16 figures; accepted for publication in Astronomy and Astrophysics for the Rosetta 2 special number</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 630, A13 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.09415">arXiv:1812.09415</a> <span> [<a href="https://arxiv.org/pdf/1812.09415">pdf</a>, <a href="https://arxiv.org/format/1812.09415">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201833807">10.1051/0004-6361/201833807 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> ROSETTA/OSIRIS observations of the 67P nucleus during the April 2016 flyby: high-resolution spectrophotometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Ferrari%2C+S">S. Ferrari</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Barucci%2C+A">A. Barucci</a>, <a href="/search/?searchtype=author&query=Massironi%2C+M">M. Massironi</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">J. D. P Deshapriya</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B+J+R">B. J. R. Davidsson</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Guti%C3%A9rrez%2C+P+J">P. J. Guti茅rrez</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a>, <a href="/search/?searchtype=author&query=Ip%2C+W+-">W. -H. Ip</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1812.09415v1-abstract-short" style="display: inline;"> In April 2016, the Rosetta spacecraft performed a low-altitude low-phase-angle flyby over the Imhotep-Khepry transition of 67P/Churyumov-Gerasimenko's nucleus. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 images with mainly 3 broadband filters in the visible at a resolution of up to 0.53 m/px and for phase angles between 0.095掳 and 62掳. Using those images, we have investigated the morphologic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.09415v1-abstract-full').style.display = 'inline'; document.getElementById('1812.09415v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.09415v1-abstract-full" style="display: none;"> In April 2016, the Rosetta spacecraft performed a low-altitude low-phase-angle flyby over the Imhotep-Khepry transition of 67P/Churyumov-Gerasimenko's nucleus. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 images with mainly 3 broadband filters in the visible at a resolution of up to 0.53 m/px and for phase angles between 0.095掳 and 62掳. Using those images, we have investigated the morphological and spectrophotometrical properties of this area. We assembled the images into coregistered color cubes. Using a 3D shape model, we produced the illumination conditions and georeference for each image. We projected the observations on a map to investigate its geomorphology. Observations were photometrically corrected using the Lommel-Seeliger disk law. Spectrophotometric analyses were performed on the coregistered color cubes. These data were used to estimate the local phase reddening. This region of the nucleus hosts numerous and varied types of terrains and features. We observe an association between a feature's nature, its reflectance, and its spectral slope. Fine material deposits exhibit an average reflectance and spectral slope, while terrains with diamictons, consolidated material, degraded outcrops, or features such as somber boulders, present a lower-than-average reflectance and higher-than-average spectral slope. Bright surfaces present here a spectral behavior consistent with terrains enriched in water-ice. We find a phase-reddening slope of 0.064{\pm}0.001{\%}/100nm/掳 at 2.7 au outbound, similarly to the one obtained at 2.3 au inbound during the February 2015 flyby. Identified as the source region of multiple jets and a host of water-ice material, the Imhotep-Khepry transition appeared in April 2016, close to the frost line, to further harbor several potential locations with exposed water-ice material among its numerous different morphological terrain units. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.09415v1-abstract-full').style.display = 'none'; document.getElementById('1812.09415v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 14 figures, 5 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.09476">arXiv:1811.09476</a> <span> [<a href="https://arxiv.org/pdf/1811.09476">pdf</a>, <a href="https://arxiv.org/ps/1811.09476">ps</a>, <a href="https://arxiv.org/format/1811.09476">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.icarus.2018.11.011">10.1016/j.icarus.2018.11.011 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Haumea's thermal emission revisited in the light of the occultation results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=M%C3%BCller%2C+T">T. M眉ller</a>, <a href="/search/?searchtype=author&query=Kiss%2C+C">Cs. Kiss</a>, <a href="/search/?searchtype=author&query=Ali-Lagoa%2C+V">V. Ali-Lagoa</a>, <a href="/search/?searchtype=author&query=Ortiz%2C+J+L">J. L. Ortiz</a>, <a href="/search/?searchtype=author&query=Lellouch%2C+E">E. Lellouch</a>, <a href="/search/?searchtype=author&query=Santos-Sanz%2C+P">P. Santos-Sanz</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Marton%2C+G">G. Marton</a>, <a href="/search/?searchtype=author&query=Mommert%2C+M">M. Mommert</a>, <a href="/search/?searchtype=author&query=Farkas-Takacs%2C+A">A. Farkas-Takacs</a>, <a href="/search/?searchtype=author&query=Thirouin%2C+A">A. Thirouin</a>, <a href="/search/?searchtype=author&query=Vilenius%2C+E">E. Vilenius</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1811.09476v1-abstract-short" style="display: inline;"> A recent occultation measurement of the dwarf planet Haumea (Ortiz et al. 2017) revealed an elongated shape with the longest axis comparable to Pluto's mean diameter. The chords also indicate a ring around Haumea's equatorial plane, where its largest moon, Hi'iaka, is also located. The Haumea occultation size estimate (equivalent diameter 1595 km) is larger than previous radiometric solutions (in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.09476v1-abstract-full').style.display = 'inline'; document.getElementById('1811.09476v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.09476v1-abstract-full" style="display: none;"> A recent occultation measurement of the dwarf planet Haumea (Ortiz et al. 2017) revealed an elongated shape with the longest axis comparable to Pluto's mean diameter. The chords also indicate a ring around Haumea's equatorial plane, where its largest moon, Hi'iaka, is also located. The Haumea occultation size estimate (equivalent diameter 1595 km) is larger than previous radiometric solutions (in the range between 1150 and 1350 km), which lowers the object's density to about 1.8 gcm-3, a value closer to the densities of other large TNOs. We present unpublished and also reprocessed Herschel and Spitzer MIR and FIR measurements. We compare 100 and 160um thermal lightcurve amplitudes - originating from Haumea itself - with models of the total measured system fluxes (ring, satellite, Haumea) from 24-350um. The combination with results derived from the occultation measurements show that Haumea's crystalline water ice surface must have a thermal inertia of ~5 SIu. We also have indications that the satellites (at least Hi'iaka) must have high geometric albedos >=0.5, otherwise the derived thermal amplitude would be inconsistent with the total measured system fluxes at 24, 70, 100, 160, 250, and 350um. The high albedos imply sizes of about 300 and 150 km for Hi'iaka and Namaka, respectively, indicating unexpectedly high densities >1.0 gcm-3 for TNOs this small, and the assumed collisional formation from Haumea's icy crust. We also estimated the thermal emission of the ring for the time period 1980-2030, showing that the contribution during the Spitzer and Herschel epochs was small, but not negligible. Due to the progressive opening of the ring plane, the ring emission will be increasing in the next decade when JWST is operational. In the MIRI 25.5um band it will also be possible to obtain a very high-quality thermal lightcurve to test the derived Haumea properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.09476v1-abstract-full').style.display = 'none'; document.getElementById('1811.09476v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures, 9 tables, accepted for publication in Icarus in November 2018; abstract has been shortened with respect to the original one</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.10424">arXiv:1809.10424</a> <span> [<a href="https://arxiv.org/pdf/1809.10424">pdf</a>, <a href="https://arxiv.org/format/1809.10424">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-3881/aae526">10.3847/1538-3881/aae526 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Models of Rosetta/OSIRIS 67P dust coma phase function </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Moreno%2C+F">Fernando Moreno</a>, <a href="/search/?searchtype=author&query=Guirado%2C+D">Daniel Guirado</a>, <a href="/search/?searchtype=author&query=Mu%C3%B1oz%2C+O">Olga Mu帽oz</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">Ivano Bertini</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">Cecilia Tubiana</a>, <a href="/search/?searchtype=author&query=Guttler%2C+C">Carsten Guttler</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">Marco Fulle</a>, <a href="/search/?searchtype=author&query=Rotundi%2C+A">Alessandra Rotundi</a>, <a href="/search/?searchtype=author&query=Della+Corte%2C+V">Vincenzo Della Corte</a>, <a href="/search/?searchtype=author&query=Ivanovski%2C+S">Stavro Ivanovski</a>, <a href="/search/?searchtype=author&query=Rinaldi%2C+G">Giovanna Rinaldi</a>, <a href="/search/?searchtype=author&query=Bockelee-Morvan%2C+D">Dominique Bockelee-Morvan</a>, <a href="/search/?searchtype=author&query=Zakharov%2C+V">Vladimir Zakharov</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">Jessica Agarwal</a>, <a href="/search/?searchtype=author&query=Mottola%2C+S">Stefano Mottola</a>, <a href="/search/?searchtype=author&query=Toth%2C+I">Imre Toth</a>, <a href="/search/?searchtype=author&query=Frattin%2C+E">Elisa Frattin</a>, <a href="/search/?searchtype=author&query=Lara%2C+L">Luisa Lara</a>, <a href="/search/?searchtype=author&query=Gutierrez%2C+P">Pedro Gutierrez</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+Y">Zhong Yi Lin</a>, <a href="/search/?searchtype=author&query=Kolokolova%2C+L">Ludmilla Kolokolova</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">Holger Sierks</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">Giampiero Naletto</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P">Philippe Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">Rafael Rodrigo</a> , et al. (17 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.10424v1-abstract-short" style="display: inline;"> The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images \citep{Bertini17}. This function show a deep minimum at phase angles near 100$^\circ$, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly-oriented aggregate particles. We show, however… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10424v1-abstract-full').style.display = 'inline'; document.getElementById('1809.10424v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.10424v1-abstract-full" style="display: none;"> The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images \citep{Bertini17}. This function show a deep minimum at phase angles near 100$^\circ$, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly-oriented aggregate particles. We show, however, that an ensamble of oriented elongated particles of a wide variety of aspect ratios, with radii $r \gtrsim$10 $渭$m, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60-70\% range. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10424v1-abstract-full').style.display = 'none'; document.getElementById('1809.10424v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by Astronomical Journal, September 26th, 2018. 21 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.03997">arXiv:1809.03997</a> <span> [<a href="https://arxiv.org/pdf/1809.03997">pdf</a>, <a href="https://arxiv.org/format/1809.03997">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201833803">10.1051/0004-6361/201833803 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Linking surface morphology, composition, and activity on the nucleus of 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Hoang%2C+V+H">V. H. Hoang</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">J. D. P. Deshapriya</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Ferrari%2C+S">S. Ferrari</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Gutierrez%2C+P+J">P. J. Gutierrez</a> , et al. (15 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.03997v1-abstract-short" style="display: inline;"> The Rosetta space probe accompanied comet 67P/Churyumov-Gerasimenko for more than two years, obtaining an unprecedented amount of unique data of the comet nucleus and inner coma. This work focuses identifying the source regions of faint jets and outbursts and on studying the spectrophotometric properties of some outbursts. We use observations acquired with the OSIRIS/NAC camera during July-October… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.03997v1-abstract-full').style.display = 'inline'; document.getElementById('1809.03997v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.03997v1-abstract-full" style="display: none;"> The Rosetta space probe accompanied comet 67P/Churyumov-Gerasimenko for more than two years, obtaining an unprecedented amount of unique data of the comet nucleus and inner coma. This work focuses identifying the source regions of faint jets and outbursts and on studying the spectrophotometric properties of some outbursts. We use observations acquired with the OSIRIS/NAC camera during July-October 2015, that is, close to perihelion. More than 200 jets of different intensities were identified directly on the nucleus. Some of the more intense outbursts appear spectrally bluer than the comet dark terrain in the vivible-to-near-infrared region. We attribute this spectral behavior to icy grains mixed with the ejected dust. Some of the jets have an extremely short lifetime. They appear on the cometary surface during the color sequence observations, and vanish in less than some few minutes after reaching their peak. We also report a resolved dust plume observed in May 2016 at a resolution of 55 cm/pixel, which allowed us to estimate an optical depth of $\sim$0.65 and an ejected mass of $\sim$ 2200 kg. We present the results on the location, duration, and colors of active sources on the nucleus of 67P from the medium-resolution (i.e., 6-10 m/pixel) images acquired close to perihelion passage. The observed jets are mainly located close to boundaries between different morphological regions. Jets depart not only from cliffs, but also from smooth and dust-covered areas, from fractures, pits, or cavities that cast shadows and favor the recondensation of volatiles. This study shows that faint jets or outbursts continuously contribute to the cometary activity close to perihelion passage, and that these events are triggered by illumination conditions. Faint jets or outbursts are not associated with a particular terrain type or morphology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.03997v1-abstract-full').style.display = 'none'; document.getElementById('1809.03997v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication on Astronomy and Astrophysics on 27 August 2018. 27 pages, 18 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 630, A7 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1803.08953">arXiv:1803.08953</a> <span> [<a href="https://arxiv.org/pdf/1803.08953">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.pss.2018.03.008">10.1016/j.pss.2018.03.008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A spectroscopic survey of the small near-Earth asteroid population: peculiar taxonomic distribution and phase reddening </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Perna%2C+D">Davide Perna</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">Maria Antonietta Barucci</a>, <a href="/search/?searchtype=author&query=Fulchignoni%2C+M">Marcello Fulchignoni</a>, <a href="/search/?searchtype=author&query=Popescu%2C+M">Marcel Popescu</a>, <a href="/search/?searchtype=author&query=Belskaya%2C+I">Irina Belskaya</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Doressoundiram%2C+A">Alain Doressoundiram</a>, <a href="/search/?searchtype=author&query=Lantz%2C+C">Cateline Lantz</a>, <a href="/search/?searchtype=author&query=Merlin%2C+F">Frederic Merlin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.08953v1-abstract-short" style="display: inline;"> We present the results of the first-ever visible spectroscopic survey fully dedicated to the small (absolute magnitude H>20) near-Earth asteroid (NEA) population. Observations have been performed at the New Technology Telescope (NTT) of the European Southern Observatory (ESO), during a 30-night Guaranteed Time Observations programme, in the framework of the European Commission financed NEOShield-2… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.08953v1-abstract-full').style.display = 'inline'; document.getElementById('1803.08953v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.08953v1-abstract-full" style="display: none;"> We present the results of the first-ever visible spectroscopic survey fully dedicated to the small (absolute magnitude H>20) near-Earth asteroid (NEA) population. Observations have been performed at the New Technology Telescope (NTT) of the European Southern Observatory (ESO), during a 30-night Guaranteed Time Observations programme, in the framework of the European Commission financed NEOShield-2 project. The visible spectra of 147 objects have been obtained and taxonomically classified. They show a peculiar taxonomic distribution, with respect to larger NEAs. In particular, olivine-rich A-types and organic-rich D-types are more abundant than what could be expected by extrapolating the taxonomic distribution of larger NEAs. Such results have implications for the investigation of the first phases of solar system history, including the delivery of prebiotic material on the early Earth. Having been obtained over a large range of solar phase angles, our data allowed us to evidence peculiar phase reddening behaviours for asteroids belonging to different taxonomic types. Low-albedo asteroids display no or limited phase reddening, compared to moderate- and high-albedo objects. This result suggests a promising novel way to distinguish primitive asteroids in the X-complex. In agreement with previous laboratory experiments, olivine-rich surfaces are the most affected by phase reddening. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.08953v1-abstract-full').style.display = 'none'; document.getElementById('1803.08953v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Planetary and Space Science. 22 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1803.04486">arXiv:1803.04486</a> <span> [<a href="https://arxiv.org/pdf/1803.04486">pdf</a>, <a href="https://arxiv.org/format/1803.04486">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty704">10.1093/mnras/sty704 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Olivine-rich asteroids in the near-Earth space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Popescu%2C+M">M. Popescu</a>, <a href="/search/?searchtype=author&query=Perna%2C+D">D. Perna</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Doressoundiram%2C+A">A. Doressoundiram</a>, <a href="/search/?searchtype=author&query=Lantz%2C+C">C. Lantz</a>, <a href="/search/?searchtype=author&query=Merlin%2C+F">F. Merlin</a>, <a href="/search/?searchtype=author&query=Belskaya%2C+I+N">I. N. Belskaya</a>, <a href="/search/?searchtype=author&query=Fulchignoni%2C+M">M. Fulchignoni</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.04486v1-abstract-short" style="display: inline;"> In the framework of a 30-night spectroscopic survey of small near-Earth asteroids (NEAs) we present new results regarding the identification of olivine-rich objects. The following NEAs were classified as A-type using visible spectra obtained with 3.6 m NTT telescope: (293726) 2007 RQ17, (444584) 2006 UK, 2012 NP, 2014 YS34, 2015 HB117, 2015 LH, 2015 TB179, 2015 TW144. We determined a relative abun… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.04486v1-abstract-full').style.display = 'inline'; document.getElementById('1803.04486v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.04486v1-abstract-full" style="display: none;"> In the framework of a 30-night spectroscopic survey of small near-Earth asteroids (NEAs) we present new results regarding the identification of olivine-rich objects. The following NEAs were classified as A-type using visible spectra obtained with 3.6 m NTT telescope: (293726) 2007 RQ17, (444584) 2006 UK, 2012 NP, 2014 YS34, 2015 HB117, 2015 LH, 2015 TB179, 2015 TW144. We determined a relative abundance of $5.4\% $ (8 out of 147 observed targets) A-types at hundred meter size range of NEAs population. The ratio is at least five times larger compared with the previously known A-types, which represent less than $\sim1\%$ of NEAs taxonomically classified. By taking into account that part of our targets may not be confirmed as olivine-rich asteroids by their near-infrared spectra, or they can have a nebular origin, our result provides an upper-limit estimation of mantle fragments at size ranges bellow 300m. Our findings are compared with the "battered-to-bits" scenario, claiming that at small sizes the olivine-rich objects should be more abundant when compared with basaltic and iron ones. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.04486v1-abstract-full').style.display = 'none'; document.getElementById('1803.04486v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 4 figures, accepted for publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.07508">arXiv:1712.07508</a> <span> [<a href="https://arxiv.org/pdf/1712.07508">pdf</a>, <a href="https://arxiv.org/format/1712.07508">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201732155">10.1051/0004-6361/201732155 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Tensile Strength of 67P/Churyumov-Gerasimenko Nucleus Material from Overhangs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Attree%2C+N">N. Attree</a>, <a href="/search/?searchtype=author&query=Groussin%2C+O">O. Groussin</a>, <a href="/search/?searchtype=author&query=Jorda%2C+L">L. Jorda</a>, <a href="/search/?searchtype=author&query=N%C3%A9bouy%2C+D">D. N茅bouy</a>, <a href="/search/?searchtype=author&query=Thomas%2C+N">N. Thomas</a>, <a href="/search/?searchtype=author&query=Brouet%2C+Y">Y. Brouet</a>, <a href="/search/?searchtype=author&query=K%C3%BChrt%2C+E">E. K眉hrt</a>, <a href="/search/?searchtype=author&query=Preusker%2C+F">F. Preusker</a>, <a href="/search/?searchtype=author&query=Scholten%2C+F">F. Scholten</a>, <a href="/search/?searchtype=author&query=Knollenberg%2C+J">J. Knollenberg</a>, <a href="/search/?searchtype=author&query=Hartogh%2C+P">P. Hartogh</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P">P. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Auger%2C+A+-">A. -T. Auger</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a> , et al. (30 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1712.07508v1-abstract-short" style="display: inline;"> We directly measure twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimate the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around one Pa or less (one to five Pa, when scaled to a metre length). The presence of eroded material at the base of mos… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.07508v1-abstract-full').style.display = 'inline'; document.getElementById('1712.07508v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.07508v1-abstract-full" style="display: none;"> We directly measure twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimate the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around one Pa or less (one to five Pa, when scaled to a metre length). The presence of eroded material at the base of most overhangs, as well as the observed collapse of two features and implied previous collapse of another, suggests that they are prone to failure and that true material strengths are close to these lower limits (although we only consider static stresses and not dynamic stress from, for example, cometary activity). Thus, a tensile strength of a few pascals is a good approximation for the tensile strength of 67P's nucleus material, which is in agreement with previous work. We find no particular trends in overhang properties with size, over the $\sim10-100$ m range studied here, or location on the nucleus. There are no obvious differences, in terms of strength, height or evidence of collapse, between the populations of overhangs on the two cometary lobes, suggesting that 67P is relatively homogenous in terms of tensile strength. Low material strengths are supportive of cometary formation as a primordial rubble pile or by collisional fragmentation of a small (tens of km) body. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.07508v1-abstract-full').style.display = 'none'; document.getElementById('1712.07508v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 11 figures. Accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 611, A33 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.10235">arXiv:1710.10235</a> <span> [<a href="https://arxiv.org/pdf/1710.10235">pdf</a>, <a href="https://arxiv.org/format/1710.10235">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx2386">10.1093/mnras/stx2386 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence of sub-surface energy storage in comet 67P from the outburst of 2016 July 3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=Della+Corte%2C+V">V. Della Corte</a>, <a href="/search/?searchtype=author&query=Feldman%2C+P+D">P. D. Feldman</a>, <a href="/search/?searchtype=author&query=Geiger%2C+B">B. Geiger</a>, <a href="/search/?searchtype=author&query=Merouane%2C+S">S. Merouane</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Gruen%2C+E">E. Gruen</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P">P. Hasselmann</a>, <a href="/search/?searchtype=author&query=Hilchenbach%2C+M">M. Hilchenbach</a>, <a href="/search/?searchtype=author&query=Hoefner%2C+S">S. Hoefner</a>, <a href="/search/?searchtype=author&query=Ivanovski%2C+S">S. Ivanovski</a>, <a href="/search/?searchtype=author&query=Kolokolova%2C+L">L. Kolokolova</a>, <a href="/search/?searchtype=author&query=Pajola%2C+M">M. Pajola</a>, <a href="/search/?searchtype=author&query=Rotundi%2C+A">A. Rotundi</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Steffl%2C+A+J">A. J. Steffl</a>, <a href="/search/?searchtype=author&query=Thomas%2C+N">N. Thomas</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a> , et al. (45 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1710.10235v1-abstract-short" style="display: inline;"> On 3 July 2016, several instruments on board ESA's Rosetta spacecraft detected signs of an outburst event on comet 67P, at a heliocentric distance of 3.32 AU from the sun, outbound from perihelion. We here report on the inferred properties of the ejected dust and the surface change at the site of the outburst. The activity coincided with the local sunrise and continued over a time interval of 14 -… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.10235v1-abstract-full').style.display = 'inline'; document.getElementById('1710.10235v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.10235v1-abstract-full" style="display: none;"> On 3 July 2016, several instruments on board ESA's Rosetta spacecraft detected signs of an outburst event on comet 67P, at a heliocentric distance of 3.32 AU from the sun, outbound from perihelion. We here report on the inferred properties of the ejected dust and the surface change at the site of the outburst. The activity coincided with the local sunrise and continued over a time interval of 14 - 68 minutes. It left a 10m-sized icy patch on the surface. The ejected material comprised refractory grains of several hundred microns in size, and sub-micron-sized water ice grains. The high dust mass production rate is incompatible with the free sublimation of crystalline water ice under solar illumination as the only acceleration process. Additional energy stored near the surface must have increased the gas density. We suggest a pressurized sub-surface gas reservoir, or the crystallization of amorphous water ice as possible causes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.10235v1-abstract-full').style.display = 'none'; document.getElementById('1710.10235v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 October, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 19 figures, 5 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS 469, S606-S625, 2017 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.10191">arXiv:1710.10191</a> <span> [<a href="https://arxiv.org/pdf/1710.10191">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.asr.2017.10.021">10.1016/j.asr.2017.10.021 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CASTAway: An Asteroid Main Belt Tour and Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Bowles%2C+N+E">N. E. Bowles</a>, <a href="/search/?searchtype=author&query=Snodgrass%2C+C">C. Snodgrass</a>, <a href="/search/?searchtype=author&query=Gibbings%2C+A">A Gibbings</a>, <a href="/search/?searchtype=author&query=Sanchez%2C+J+P">J. P. Sanchez</a>, <a href="/search/?searchtype=author&query=Arnold%2C+J+A">J. A. Arnold</a>, <a href="/search/?searchtype=author&query=Eccleston%2C+P">P. Eccleston</a>, <a href="/search/?searchtype=author&query=Andert%2C+T">T. Andert</a>, <a href="/search/?searchtype=author&query=Probst%2C+A">A. Probst</a>, <a href="/search/?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/?searchtype=author&query=Vandaele%2C+A+C">A. C. Vandaele</a>, <a href="/search/?searchtype=author&query=de+Leon%2C+J">J. de Leon</a>, <a href="/search/?searchtype=author&query=Nathues%2C+A">A. Nathues</a>, <a href="/search/?searchtype=author&query=Thomas%2C+I+R">I. R. Thomas</a>, <a href="/search/?searchtype=author&query=Thomas%2C+N">N. Thomas</a>, <a href="/search/?searchtype=author&query=Jorda%2C+L">L. Jorda</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Haack%2C+H">H. Haack</a>, <a href="/search/?searchtype=author&query=Green%2C+S+F">S. F. Green</a>, <a href="/search/?searchtype=author&query=Carry%2C+B">B. Carry</a>, <a href="/search/?searchtype=author&query=Hanna%2C+K+L+D">K. L. Donaldson Hanna</a>, <a href="/search/?searchtype=author&query=Jorgensen%2C+J+L">J. Leif Jorgensen</a>, <a href="/search/?searchtype=author&query=Kereszturi%2C+A">A. Kereszturi</a>, <a href="/search/?searchtype=author&query=DeMeo%2C+F+E">F. E. DeMeo</a>, <a href="/search/?searchtype=author&query=Patel%2C+M+R">M. R. Patel</a>, <a href="/search/?searchtype=author&query=Davies%2C+J+K">J. K. Davies</a> , et al. (20 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1710.10191v1-abstract-short" style="display: inline;"> CASTAway is a mission concept to explore our Solar System's main asteroid belt. Asteroids and comets provide a window into the formation and evolution of our Solar System and the composition of these objects can be inferred from space-based remote sensing using spectroscopic techniques. Variations in composition across the asteroid populations provide a tracer for the dynamical evolution of the So… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.10191v1-abstract-full').style.display = 'inline'; document.getElementById('1710.10191v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.10191v1-abstract-full" style="display: none;"> CASTAway is a mission concept to explore our Solar System's main asteroid belt. Asteroids and comets provide a window into the formation and evolution of our Solar System and the composition of these objects can be inferred from space-based remote sensing using spectroscopic techniques. Variations in composition across the asteroid populations provide a tracer for the dynamical evolution of the Solar System. The mission combines a long-range (point source) telescopic survey of over 10,000 objects, targeted close encounters with 10 to 20 asteroids and serendipitous searches to constrain the distribution of smaller (e.g. 10 m) size objects into a single concept. With a carefully targeted trajectory that loops through the asteroid belt, CASTAway would provide a comprehensive survey of the main belt at multiple scales. The scientific payload comprises a 50 cm diameter telescope that includes an integrated low-resolution (R = 30 to 100) spectrometer and visible context imager, a thermal (e.g. 6 to 16 microns) imager for use during the flybys, and modified star tracker cameras to detect small (approx. 10 m) asteroids. The CASTAway spacecraft and payload have high levels of technology readiness and are designed to fit within the programmatic and cost caps for a European Space Agency medium class mission, whilst delivering a significant increase in knowledge of our Solar System. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.10191v1-abstract-full').style.display = 'none'; document.getElementById('1710.10191v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 October, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, accepted by Advances in Space Research October 2017</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.01356">arXiv:1710.01356</a> <span> [<a href="https://arxiv.org/pdf/1710.01356">pdf</a>, <a href="https://arxiv.org/format/1710.01356">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.icarus.2015.11.023">10.1016/j.icarus.2015.11.023 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Asteroid (21) Lutetia: Disk-resolved Photometric Analysis of Baetica Region </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Leyrat%2C+C">C. Leyrat</a>, <a href="/search/?searchtype=author&query=Carvano%2C+J+M">J. M. Carvano</a>, <a href="/search/?searchtype=author&query=Lazzaro%2C+D">D. Lazzaro</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1710.01356v1-abstract-short" style="display: inline;"> (21) Lutetia has been visited by Rosetta mission on July 2010 and observed with a phase angle ranging from 0.15 to 156.8 degrees. The Baetica region, located at the north pole has been extensively observed by OSIRIS cameras system. Baetica encompass a region called North Pole Crater Cluster (NPCC), shows a cluster of superposed craters which presents signs of variegation at the small phase angle i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.01356v1-abstract-full').style.display = 'inline'; document.getElementById('1710.01356v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.01356v1-abstract-full" style="display: none;"> (21) Lutetia has been visited by Rosetta mission on July 2010 and observed with a phase angle ranging from 0.15 to 156.8 degrees. The Baetica region, located at the north pole has been extensively observed by OSIRIS cameras system. Baetica encompass a region called North Pole Crater Cluster (NPCC), shows a cluster of superposed craters which presents signs of variegation at the small phase angle images. For studying the location, we used 187 images distributed throughout 14 filter recorded by the NAC (Narrow Angle Camera) and WAC (Wide Angle Camera) taken during the fly-by. We photometrically modeled the region using Minnaert disk-function and Akimov phase function to finally reconstruct a resolved spectral slope map at 5 and 20 degrees of phase angle. We observed a dichotomy between Gallicum and Danuvius-Sarnus Labes in the NPCC, but no significant phase reddening. In the next step, we applied the Hapke (2008, 2012) model for the NAC F82+F22 (649.2 nm), WAC F13 (375 nm) and WAC F17 (631.6 nm), enabling us to compose the normal albedo and Hapke parameter maps for NAC F82+F22. On Baetica, the 649 nm global properties are: geometric albedo of 0.205+-0.005, the average single-scattering albedo of 0.181+-0.005, the average asymmetric factor of -0.342+-0.003, the average shadow-hiding opposition effect amplitude and width respectivelly of 0.824+-0.002 and 0.040+-0.0007, the average roughness slope of 11.45+-3 deg. and the average porosity is 85+-0.2%. In the NPCC, the normal albedo variegation among the craters walls reach 8% brighter for Gallicum Labes and 2% fainter for Danuvius Labes. The Hapke parameter maps also show a dichotomy at the opposition effect coefficients, single-scattering albedo and asymmetric factor, that may be attributed to the maturation degree of the regolith or to compositonal variation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.01356v1-abstract-full').style.display = 'none'; document.getElementById('1710.01356v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Icarus 267, 135-153, 2016 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1709.06747">arXiv:1709.06747</a> <span> [<a href="https://arxiv.org/pdf/1709.06747">pdf</a>, <a href="https://arxiv.org/ps/1709.06747">ps</a>, <a href="https://arxiv.org/format/1709.06747">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201731676">10.1051/0004-6361/201731676 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The thermal emission of Centaurs and Trans-Neptunian objects at millimeter wavelengths from ALMA observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Lellouch%2C+E">E. Lellouch</a>, <a href="/search/?searchtype=author&query=Moreno%2C+R">R. Moreno</a>, <a href="/search/?searchtype=author&query=M%C3%BCller%2C+T">T. M眉ller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Santos-Sanz%2C+P">P. Santos-Sanz</a>, <a href="/search/?searchtype=author&query=Moullet%2C+A">A. Moullet</a>, <a href="/search/?searchtype=author&query=Gurwell%2C+M">M. Gurwell</a>, <a href="/search/?searchtype=author&query=Stansberry%2C+J">J. Stansberry</a>, <a href="/search/?searchtype=author&query=Leiva%2C+R">R. Leiva</a>, <a href="/search/?searchtype=author&query=Sicardy%2C+B">B. Sicardy</a>, <a href="/search/?searchtype=author&query=Butler%2C+B">B. Butler</a>, <a href="/search/?searchtype=author&query=Boissier%2C+J">J. Boissier</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1709.06747v1-abstract-short" style="display: inline;"> The sensitivity of ALMA makes it possible to detect thermal mm/submm emission from small/distant Solar System bodies at the sub-mJy level. Measured fluxes are primarily sensitive to the objects' diameters, but deriving precise sizes is somewhat hampered by the uncertain effective emissivity at these wavelengths. Following Brown and Butler (2017) who presented ALMA data for four binary TNOs, we rep… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.06747v1-abstract-full').style.display = 'inline'; document.getElementById('1709.06747v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1709.06747v1-abstract-full" style="display: none;"> The sensitivity of ALMA makes it possible to detect thermal mm/submm emission from small/distant Solar System bodies at the sub-mJy level. Measured fluxes are primarily sensitive to the objects' diameters, but deriving precise sizes is somewhat hampered by the uncertain effective emissivity at these wavelengths. Following Brown and Butler (2017) who presented ALMA data for four binary TNOs, we report ALMA 1.29 mm measurements of four Centaurs (2002 GZ$_{32}$, Bienor, Chiron, Chariklo) and two TNOs (Huya and Makemake), sampling a range of size, albedo and composition. These thermal fluxes are combined with mid/far-infrared fluxes to derive the relative emissivity at radio (mm/submm) wavelengths, using NEATM and thermophysical models. We reassess earlier thermal measurements of these and other objects -- including Pluto/Charon and Varuna -- exploring effects due to non-spherical shape and varying apparent pole orientation, and show that those can be key for reconciling previous diameter determinations and correctly estimating the spectral emissivities. We also evaluate the possible contribution to thermal fluxes of established (Chariklo) or claimed (Chiron) ring systems. As a general conclusion, all the objects, except Makemake, have radio emissivities significantly lower than unity. Although the emissivity values show diversity, we do not find any significant trend with physical parameters such as diameter, composition, beaming factor, albedo, or color, but we suggest that the emissivity could be correlated with grain size. The mean relative radio emissivity is found to be 0.70$\pm$0.13, a value that we recommend for the analysis of further mm/submm data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1709.06747v1-abstract-full').style.display = 'none'; document.getElementById('1709.06747v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 September, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 11 figures. Accepted for publication in Astronomy & Astrophysics, 20 Sept. 2017</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 608, A45 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.06812">arXiv:1707.06812</a> <span> [<a href="https://arxiv.org/pdf/1707.06812">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1726">10.1093/mnras/stx1726 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Seasonal Mass Transfer on the Nucleus of Comet 67P/Chuyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Mottola%2C+S">S. Mottola</a>, <a href="/search/?searchtype=author&query=Hviid%2C+S+F">S. F. Hviid</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=K%C3%BChrt%2C+E">E. K眉hrt</a>, <a href="/search/?searchtype=author&query=Skorov%2C+Y">Y. Skorov</a>, <a href="/search/?searchtype=author&query=Otto%2C+K">K. Otto</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=Schr%C3%B6der%2C+S+E">S. E. Schr枚der</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Pajola%2C+M">M. Pajola</a>, <a href="/search/?searchtype=author&query=Shi%2C+X">X. Shi</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Toth%2C+I">I. Toth</a>, <a href="/search/?searchtype=author&query=Preusker%2C+F">F. Preusker</a>, <a href="/search/?searchtype=author&query=Scholten%2C+F">F. Scholten</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P">P. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a> , et al. (25 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.06812v1-abstract-short" style="display: inline;"> We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material that indicates back fall originating from the activ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.06812v1-abstract-full').style.display = 'inline'; document.getElementById('1707.06812v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.06812v1-abstract-full" style="display: none;"> We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material that indicates back fall originating from the active south. Decimetre sized chunks contain water ice and their trajectories are influenced by an anti-solar force instigated by sublimation. OSIRIS observations suggest that up to 20 % of the particles directly return to the nucleus surface taking several hours of travel time. The back fall covered northern areas are active if illuminated but produce mainly water vapour. The decimetre chunks from the nucleus surface are too small to contain more volatile compounds such as CO 2 or CO. This causes a north-south dichotomy of the composition measurements in the coma. Active particles are trapped in the gravitational minimum of Hapi during northern winter. They are "shock frozen" and only reactivated when the comet approaches the sun after its aphelion passage. The insolation of the big cavity is enhanced by self-heating, i. e. reflection and IR radiation from the walls. This, together with the pristinity of the active back fall, explains the early observed activity of the Hapi region. Sobek may be a role model for the consolidated bottom of Hapi. Mass transfer in the case of 67P strongly influences the evolution of the nucleus and the interpretation of coma measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.06812v1-abstract-full').style.display = 'none'; document.getElementById('1707.06812v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 20 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society stx1726, 13 July 2017 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.02945">arXiv:1707.02945</a> <span> [<a href="https://arxiv.org/pdf/1707.02945">pdf</a>, <a href="https://arxiv.org/format/1707.02945">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1275">10.1093/mnras/stx1275 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The highly active Anhur-Bes regions in the 67P/Churyumov - Gerasimenko comet: results from OSIRIS/ROSETTA observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Lee%2C+J+C">J. C. Lee</a>, <a href="/search/?searchtype=author&query=Ferrari%2C+S">S. Ferrari</a>, <a href="/search/?searchtype=author&query=Massironi%2C+M">M. Massironi</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">J. D. P Deshapriya</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. R. El-Maarry</a>, <a href="/search/?searchtype=author&query=Giacomini%2C+L">L. Giacomini</a>, <a href="/search/?searchtype=author&query=Mottola%2C+S">S. Mottola</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Ip%2C+W+H">W. H. Ip</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+Y">Z. Y. Lin</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M">M. A'Hearn</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a> , et al. (29 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.02945v1-abstract-short" style="display: inline;"> The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.02945v1-abstract-full').style.display = 'inline'; document.getElementById('1707.02945v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.02945v1-abstract-full" style="display: none;"> The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits, and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur/Bes boundary during/after the perihelion passage, close to the area where exposed CO$_2$ and H$_2$O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit, and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.02945v1-abstract-full').style.display = 'none'; document.getElementById('1707.02945v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 15 figures, published online on 24 May 2017 on Mon. Not. R. Astron. Soc. stx1275, https://doi.org/10.1093/mnras/stx1275</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.00734">arXiv:1707.00734</a> <span> [<a href="https://arxiv.org/pdf/1707.00734">pdf</a>, <a href="https://arxiv.org/format/1707.00734">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1691">10.1093/mnras/stx1691 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Hviid%2C+S+F">S. F. Hviid</a>, <a href="/search/?searchtype=author&query=Mottola%2C+S">S. Mottola</a>, <a href="/search/?searchtype=author&query=Kuehrt%2C+E">E. Kuehrt</a>, <a href="/search/?searchtype=author&query=Preusker%2C+F">F. Preusker</a>, <a href="/search/?searchtype=author&query=Scholten%2C+F">F. Scholten</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=de+Niem%2C+D">D. de Niem</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Pajola%2C+M">M. Pajola</a>, <a href="/search/?searchtype=author&query=Hofmann%2C+M">M. Hofmann</a>, <a href="/search/?searchtype=author&query=Hu%2C+X">X. Hu</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+-">Z. -Y. Lin</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Gicquel%2C+A">A. Gicquel</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a> , et al. (29 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.00734v2-abstract-short" style="display: inline;"> We present a statistical analysis of the distribution of large scale topographic features on comet 67P/Churyumov-Gerasimenko. We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 +- 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbita… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.00734v2-abstract-full').style.display = 'inline'; document.getElementById('1707.00734v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.00734v2-abstract-full" style="display: none;"> We present a statistical analysis of the distribution of large scale topographic features on comet 67P/Churyumov-Gerasimenko. We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 +- 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the northern hemisphere topography is dominated by structures on the 100~m scale while the southern hemisphere topography, illuminated at perihelion, is dominated by 10~m scale terrain features. Our study suggest that the current size of a cliff is controlled not only by material cohesion but by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, i.e. its evolutionary age. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.00734v2-abstract-full').style.display = 'none'; document.getElementById('1707.00734v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.02729">arXiv:1706.02729</a> <span> [<a href="https://arxiv.org/pdf/1706.02729">pdf</a>, <a href="https://arxiv.org/ps/1706.02729">ps</a>, <a href="https://arxiv.org/format/1706.02729">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1441">10.1093/mnras/stx1441 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modeling of the outburst on July 29th, 2015 observed with OSIRIS cameras in the southern hemisphere of comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Gicquel%2C+A">A. Gicquel</a>, <a href="/search/?searchtype=author&query=Rose%2C+M">M. Rose</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Hearn%2C+M+F+A">M. F. A Hearn</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=Fougere%2C+N">N. Fougere</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+-">Z. -Y. Lin</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a> , et al. (38 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1706.02729v1-abstract-short" style="display: inline;"> Images of the nucleus and the coma (gas and dust) of comet 67P/Churyumov- Gerasimenko have been acquired by the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras since March 2014 using both the Wide Angle Camera (WAC) and the Narrow Angle Camera (NAC). We use images from the NAC camera to study a bright outburst observed in the southern hemisphere on July 29, 2015. The hi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.02729v1-abstract-full').style.display = 'inline'; document.getElementById('1706.02729v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.02729v1-abstract-full" style="display: none;"> Images of the nucleus and the coma (gas and dust) of comet 67P/Churyumov- Gerasimenko have been acquired by the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras since March 2014 using both the Wide Angle Camera (WAC) and the Narrow Angle Camera (NAC). We use images from the NAC camera to study a bright outburst observed in the southern hemisphere on July 29, 2015. The high spatial resolution of the NAC is needed to localize the source point of the outburst on the surface of the nucleus. The heliocentric distance is 1.25 au and the spacecraft-comet distance is 186 km. Aiming to better understand the physics that led to the outgassing, we used the Direct Simulation Monte Carlo (DSMC) method to study the gas flow close to the nucleus and the dust trajectories. The goal is to understand the mechanisms producing the outburst. We reproduce the opening angle of the outburst in the model and constrain the outgassing ratio between the outburst source and the local region. The outburst is in fact a combination of both gas and dust, in which the active surface is approximately 10 times more active than the average rate found in the surrounding areas. We need a number of dust particles 7.83 $\times$ 10$^{11}$ - 6.90 $\times$ 10$^{15}$ (radius 1.97 - 185 渭m), which corresponds to a mass of dust 220 - 21 $\times$ 10$^{3}$kg. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.02729v1-abstract-full').style.display = 'none'; document.getElementById('1706.02729v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> MN-17-1040-MJ.R1 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.09117">arXiv:1705.09117</a> <span> [<a href="https://arxiv.org/pdf/1705.09117">pdf</a>, <a href="https://arxiv.org/format/1705.09117">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201630354">10.1051/0004-6361/201630354 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> TNOs are Cool: a survey of the Transneptunian Region XII. Thermal light curves of Haumea, 2003 VS2 and 2003 AZ84 with Herschel Space Observatory-PACS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Santos-Sanz%2C+P">P. Santos-Sanz</a>, <a href="/search/?searchtype=author&query=Lellouch%2C+E">E. Lellouch</a>, <a href="/search/?searchtype=author&query=Groussin%2C+O">O. Groussin</a>, <a href="/search/?searchtype=author&query=Lacerda%2C+P">P. Lacerda</a>, <a href="/search/?searchtype=author&query=Mueller%2C+T+G">T. G. Mueller</a>, <a href="/search/?searchtype=author&query=Ortiz%2C+J+L">J. L. Ortiz</a>, <a href="/search/?searchtype=author&query=Kiss%2C+C">C. Kiss</a>, <a href="/search/?searchtype=author&query=Vilenius%2C+E">E. Vilenius</a>, <a href="/search/?searchtype=author&query=Stansberry%2C+J">J. Stansberry</a>, <a href="/search/?searchtype=author&query=Duffard%2C+R">R. Duffard</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Jorda%2C+L">L. Jorda</a>, <a href="/search/?searchtype=author&query=Thirouin%2C+A">A. Thirouin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.09117v1-abstract-short" style="display: inline;"> Time series observations of the dwarf planet Haumea and the Plutinos 2003VS2 and 2003AZ84 with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects were acquired as part of the TNOs are Cool Herschel Space Observatory key programme. We search for the thermal light curves at 100 and 160um of Haumea and 2003AZ84, and at 70 and 160um for 2003VS2 by means of phot… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.09117v1-abstract-full').style.display = 'inline'; document.getElementById('1705.09117v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.09117v1-abstract-full" style="display: none;"> Time series observations of the dwarf planet Haumea and the Plutinos 2003VS2 and 2003AZ84 with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects were acquired as part of the TNOs are Cool Herschel Space Observatory key programme. We search for the thermal light curves at 100 and 160um of Haumea and 2003AZ84, and at 70 and 160um for 2003VS2 by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Haumea's thermal light curve is clearly detected at 100 and 160um. The effect of the reported dark spot is apparent at 100um. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (< 0.5 MKS) and a high phase integral (> 0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003VS2 is not firmly detected at 70 and at 160um but a thermal inertia of 2+/-0.5 MKS can be derived from these data. The thermal light curve of 2003AZ84 is not firmly detected at 100um. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003AZ84, obtaining a close to pole-on orientation as the most likely for this TNO. For the three TNOs, the thermal inertias derived from light curve analyses or from the thermophysical analysis of the mean thermal fluxes confirm the generally small or very small surface thermal inertias of the TNO population, which is consistent with a statistical mean value of 2.5+/-0.5 MKS. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.09117v1-abstract-full').style.display = 'none'; document.getElementById('1705.09117v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 12 figures. Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 604, A95 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.03740">arXiv:1705.03740</a> <span> [<a href="https://arxiv.org/pdf/1705.03740">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.pss.2017.04.018">10.1016/j.pss.2017.04.018 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Distance determination method of dust particles using Rosetta OSIRIS NAC and WAC data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Drolshagen%2C+E">E. Drolshagen</a>, <a href="/search/?searchtype=author&query=Ott%2C+T">T. Ott</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+I">P. I. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Gicquel%2C+A">A. Gicquel</a> , et al. (20 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.03740v1-abstract-short" style="display: inline;"> The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust particles in the comet's coma, the two cameras to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.03740v1-abstract-full').style.display = 'inline'; document.getElementById('1705.03740v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.03740v1-abstract-full" style="display: none;"> The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust particles in the comet's coma, the two cameras took images at the same time. The aim of this work is to use these simultaneous double camera observations to calculate the dust particles' distance to the spacecraft. As the two cameras are mounted on the spacecraft with an offset of 70 cm, the distance of particles observed by both cameras can be determined by a shift of the particles' apparent trails on the images. This paper presents first results of the ongoing work, introducing the distance determination method for the OSIRIS instrument and the analysis of an example particle. We note that this method works for particles in the range of about 500 m - 6000 m from the spacecraft. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.03740v1-abstract-full').style.display = 'none'; document.getElementById('1705.03740v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.00012">arXiv:1611.00012</a> <span> [<a href="https://arxiv.org/pdf/1611.00012">pdf</a>, <a href="https://arxiv.org/format/1611.00012">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw2511">10.1093/mnras/stw2511 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Decimetre-scaled spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Barucci%2C+A">A. Barucci</a>, <a href="/search/?searchtype=author&query=Preusker%2C+F">F. Preusker</a>, <a href="/search/?searchtype=author&query=Scholten%2C+F">F. Scholten</a>, <a href="/search/?searchtype=author&query=Jorda%2C+L">L. Jorda</a>, <a href="/search/?searchtype=author&query=Pommerol%2C+A">A. Pommerol</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M">M. A'Hearn</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B+J+R">B. J. R. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Giquel%2C+A">A. Giquel</a>, <a href="/search/?searchtype=author&query=Groussin%2C+O">O. Groussin</a>, <a href="/search/?searchtype=author&query=Gutierrez%2C+P+J">P. J. Gutierrez</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a> , et al. (21 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.00012v1-abstract-short" style="display: inline;"> We present the results of the photometric and spectrophotometric properties of the 67P/Churyumov-Gerasimenko nucleus derived with the OSIRIS instrument during the closest fly-by over the comet, which took place on 14 th February 2015 at a distance of {\~} 6 km from the surface. Several images covering the 0掳-33掳 phase angle range were acquired, and the spatial resolution achieved was 11 cm/pxl. Th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.00012v1-abstract-full').style.display = 'inline'; document.getElementById('1611.00012v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.00012v1-abstract-full" style="display: none;"> We present the results of the photometric and spectrophotometric properties of the 67P/Churyumov-Gerasimenko nucleus derived with the OSIRIS instrument during the closest fly-by over the comet, which took place on 14 th February 2015 at a distance of {\~} 6 km from the surface. Several images covering the 0掳-33掳 phase angle range were acquired, and the spatial resolution achieved was 11 cm/pxl. The flown-by region is located on the big lobe of the comet, near the borders of the Ash, Apis and Imhotep regions. Our analysis shows that this region features local heterogeneities at the decimetre scale. We observed difference of reflectance up to 40{\%} between bright spots and sombre regions, and spectral slope variations up to 50{\%}. The spectral reddening effect observed globally on the comet surface by Fornasier et al. (2015) is also observed locally on this region, but with a less steep behaviour. We note that numerous metre-sized boulders, which exhibit a smaller opposition effect, also appear spectrally redder than their surroundings. In this region, we found no evidence linking observed bright spots to exposed water-ice-rich material. We fitted our dataset using the Hapke 2008 photometric model. The region overflown is globally as dark as the whole nucleus (geometric albedo of 6.8{\%}) and it has a high porosity value in the uppermost-layers (86{\%}). These results of the photometric analysis at a decimetre scale indicate that the photometric properties of the flown-by region are similar to those previously found for the whole nucleus. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.00012v1-abstract-full').style.display = 'none'; document.getElementById('1611.00012v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 16 figures, 5 tables, (also presented at DPS48/ESPC11: http://cdsads.u-strasbg.fr/abs/2016DPS....4830004F)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.07743">arXiv:1609.07743</a> <span> [<a href="https://arxiv.org/pdf/1609.07743">pdf</a>, <a href="https://arxiv.org/format/1609.07743">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw2409">10.1093/mnras/stw2409 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Summer fireworks on comet 67P </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+-">Z. -Y. Lin</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. R. El-Maarry</a>, <a href="/search/?searchtype=author&query=Pajola%2C+M">M. Pajola</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a> , et al. (30 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.07743v1-abstract-short" style="display: inline;"> During its two years mission around comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features associated to the activity of the nucleus, such as localized dust and gas jets. Here we report on series of more energetic transient events observed during the three… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07743v1-abstract-full').style.display = 'inline'; document.getElementById('1609.07743v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.07743v1-abstract-full" style="display: none;"> During its two years mission around comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features associated to the activity of the nucleus, such as localized dust and gas jets. Here we report on series of more energetic transient events observed during the three months surrounding the comet's perihelion passage in August 2015. We detected and characterized 34 outbursts with the Rosetta cameras, one every 2.4 nucleus rotation. We identified 3 main dust plume morphologies associated to these events: a narrow jet, a broad fan, and more complex plumes featuring both previous types together. These plumes are comparable in scale and temporal variation to what has been observed on other comets. We present a map of the outbursts source locations, and discuss the associated topography. We find that the spatial distribution sources on the nucleus correlates well with morphological region boundaries, especially in areas marked by steep scarps or cliffs. Outbursts occur either in the early morning or shortly after the local noon, indicating two potential processes: Morning outbursts may be triggered by thermal stresses linked to the rapid change of temperature, afternoon events are most likely related to the diurnal or seasonal heat wave reaching volatiles buried under the first surface layer. In addition, we propose that some events can be the result of a completely different mechanism, in which most of the dust is released upon the collapse of a cliff. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07743v1-abstract-full').style.display = 'none'; document.getElementById('1609.07743v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">MNRAS (2016)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.00551">arXiv:1609.00551</a> <span> [<a href="https://arxiv.org/pdf/1609.00551">pdf</a>, <a href="https://arxiv.org/format/1609.00551">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201628764">10.1051/0004-6361/201628764 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of exposed H$_2$O ice on the nucleus of comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Filacchione%2C+G">G. Filacchione</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Raponi%2C+A">A. Raponi</a>, <a href="/search/?searchtype=author&query=Deshapriya%2C+J+D+P">J. D. P. Deshapriya</a>, <a href="/search/?searchtype=author&query=Tosi%2C+F">F. Tosi</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">M. Ciarniello</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Capaccioni%2C+F">F. Capaccioni</a>, <a href="/search/?searchtype=author&query=Pommerol%2C+A">A. Pommerol</a>, <a href="/search/?searchtype=author&query=Massironi%2C+M">M. Massironi</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=Merlin%2C+F">F. Merlin</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Fulchignoni%2C+M">M. Fulchignoni</a>, <a href="/search/?searchtype=author&query=Guilbert-Lepoutre%2C+A">A. Guilbert-Lepoutre</a>, <a href="/search/?searchtype=author&query=Perna%2C+D">D. Perna</a>, <a href="/search/?searchtype=author&query=Capria%2C+M+T">M. T. Capria</a>, <a href="/search/?searchtype=author&query=Hasselmann%2C+P+H">P. H. Hasselmann</a>, <a href="/search/?searchtype=author&query=Rousseau%2C+B">B. Rousseau</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Bockelee-Morvan%2C+D">D. Bockelee-Morvan</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=De+Sanctis%2C+C">C. De Sanctis</a> , et al. (20 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.00551v1-abstract-short" style="display: inline;"> Since the orbital insertion of the Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P/C-G) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus. The aim of this work is to search for the presence of H$_2$O on the nucleus which, in general, appears very dark and rich in dehydrated organic material. After selecting i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.00551v1-abstract-full').style.display = 'inline'; document.getElementById('1609.00551v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.00551v1-abstract-full" style="display: none;"> Since the orbital insertion of the Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P/C-G) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus. The aim of this work is to search for the presence of H$_2$O on the nucleus which, in general, appears very dark and rich in dehydrated organic material. After selecting images of the bright spots which could be good candidates to search for H$_2$O ice, taken at high resolution by OSIRIS, we check for spectral cubes of the selected coordinates to identify these spots observed by VIRTIS. The selected OSIRIS images were processed with the OSIRIS standard pipeline and corrected for the illumination conditions for each pixel using the Lommel-Seeliger disk law. The spots with higher I/F were selected and then analysed spectrophotometrically and compared with the surrounding area. We selected 13 spots as good targets to be analysed by VIRTIS to search for the 2 micron absorption band of water ice in the VIRTIS spectral cubes. Out of the 13 selected bright spots, eight of them present positive H$_2$O ice detection on the VIRTIS data. A spectral analysis was performed and the approximate temperature of each spot was computed. The H$_2$O ice content was confirmed by modeling the spectra with mixing (areal and intimate) of H$_2$O ice and dark terrain, using Hapke's radiative transfer modeling. We also present a detailed analysis of the detected spots. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.00551v1-abstract-full').style.display = 'none'; document.getElementById('1609.00551v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">paper in press in A&A, 13 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 595, A102 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.08774">arXiv:1608.08774</a> <span> [<a href="https://arxiv.org/pdf/1608.08774">pdf</a>, <a href="https://arxiv.org/ps/1608.08774">ps</a>, <a href="https://arxiv.org/format/1608.08774">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw2117">10.1093/mnras/stw2117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sublimation of icy aggregates in the coma of comet 67P/Churyumov-Gerasimenko detected with the OSIRIS cameras onboard Rosetta </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Gicquel%2C+A">A. Gicquel</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+-">Z. -Y. Lin</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Frattin%2C+E">E. Frattin</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. R. El-Maarry</a> , et al. (36 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.08774v1-abstract-short" style="display: inline;"> Beginning in March 2014, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov-Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.08774v1-abstract-full').style.display = 'inline'; document.getElementById('1608.08774v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.08774v1-abstract-full" style="display: none;"> Beginning in March 2014, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov-Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet's dust jets. We analyzed the dust monitoring observations shortly after the southern vernal equinox on May 30 and 31, 2015 with the WAC at the heliocentric distance Rh = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness as a function of the distance of the jet is much steeper than the background coma, which is a first indication of sublimation. We adapted a model of sublimation of icy aggregates and studied the effect as a function of the physical properties of the aggregates (composition and size). The major finding of this article was that through the sublimation of the aggregates of dirty grains (radius a between 5 microm and 50 microm) we were able to completely reproduce the radial brightness profile of a jet beyond 4 km from the nucleus. To reproduce the data we needed to inject a number of aggregates between 8.5 x $10^{13}$ and 8.5 x $10^{10}$ for a = 5 microm and 50 microm respectively, or an initial mass of $H_2O$ ice around 22kg. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.08774v1-abstract-full').style.display = 'none'; document.getElementById('1608.08774v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 7 figures, 3 tables, special issue "The ESLAB 50 Symposium - spacecraft at comets from 1P/Halley to 67P/Churyumov-Gerasimenko" in the Monthly Notices of the Royal Astronomical Society</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.07933">arXiv:1608.07933</a> <span> [<a href="https://arxiv.org/pdf/1608.07933">pdf</a>, <a href="https://arxiv.org/format/1608.07933">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw2179">10.1093/mnras/stw2179 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Acceleration of Individual, Decimetre-sized Aggregates in the Lower Coma of Comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Guettler%2C+C">C. Guettler</a>, <a href="/search/?searchtype=author&query=Hoefner%2C+S">S. Hoefner</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Deller%2C+J">J. Deller</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Gicquel%2C+A">A. Gicquel</a> , et al. (19 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.07933v1-abstract-short" style="display: inline;"> We present OSIRIS/NAC observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained in January 2016 when the comet was at 2 AU from the Sun out-bound from perihelion. We measure the acceleration of individual aggregates through a two-hour image series. Approximately 50% of the aggregates… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07933v1-abstract-full').style.display = 'inline'; document.getElementById('1608.07933v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.07933v1-abstract-full" style="display: none;"> We present OSIRIS/NAC observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained in January 2016 when the comet was at 2 AU from the Sun out-bound from perihelion. We measure the acceleration of individual aggregates through a two-hour image series. Approximately 50% of the aggregates are accelerated away from the nucleus, and 50% towards it, and likewise towards either horizontal direction. The accelerations are up to one order of magnitude stronger than local gravity, and are most simply explained by the combined effect of gas drag accelerating all aggregates upwards, and the recoil force from asymmetric outgassing, either from rotating aggregates with randomly oriented spin axes and sufficient thermal inertia to shift the temperature maximum away from an aggregate's subsolar region, or from aggregates with variable ice content. At least 10% of the aggregates will escape the gravity field of the nucleus and feed the comet's debris trail, while others may fall back to the surface and contribute to the deposits covering parts of the northern hemisphere. The rocket force plays a crucial role in pushing these aggregates back towards the surface. Our observations show the future back fall material in the process of ejection, and provide the first direct measurement of the acceleration of aggregates in the innermost coma (<2km) of a comet, where gas drag is still significant. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07933v1-abstract-full').style.display = 'none'; document.getElementById('1608.07933v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 14 figures, accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.05632">arXiv:1607.05632</a> <span> [<a href="https://arxiv.org/pdf/1607.05632">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-6256/152/5/130">10.3847/0004-6256/152/5/130 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Changes in the physical environment of the inner coma of 67P/Churyumov-Gerasimenko with decreasing heliocentric distance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Lara%2C+L+M">L. M. Lara</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=La+Forgia%2C+F">F. La Forgia</a>, <a href="/search/?searchtype=author&query=Giquel%2C+A">A. Giquel</a>, <a href="/search/?searchtype=author&query=Kovacs%2C+G">G. Kovacs</a>, <a href="/search/?searchtype=author&query=Knollenberg%2C+J">J. Knollenberg</a>, <a href="/search/?searchtype=author&query=Lazzarin%2C+M">M. Lazzarin</a>, <a href="/search/?searchtype=author&query=Lin%2C+Z+-">Z. -Y. Lin</a>, <a href="/search/?searchtype=author&query=Shi%2C+X">X. Shi</a>, <a href="/search/?searchtype=author&query=Snodgrass%2C+C">C. Snodgrass</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+M">P. M. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Boudreault%2C+S">S. Boudreault</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=DaDeppo%2C+V">V. DaDeppo</a> , et al. (21 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1607.05632v1-abstract-short" style="display: inline;"> The Wide Angle Camera of the OSIRIS instrument on board the Rosetta spacecraft is equipped with several narrowband filters that are centered on the emission lines and bands of various fragment species. These are used to determine the evolution of the production and spatial distribution of the gas in the inner coma of comet 67P with time and heliocentric distance, here between 2.6 - 1.3 AU pre-peri… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.05632v1-abstract-full').style.display = 'inline'; document.getElementById('1607.05632v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.05632v1-abstract-full" style="display: none;"> The Wide Angle Camera of the OSIRIS instrument on board the Rosetta spacecraft is equipped with several narrowband filters that are centered on the emission lines and bands of various fragment species. These are used to determine the evolution of the production and spatial distribution of the gas in the inner coma of comet 67P with time and heliocentric distance, here between 2.6 - 1.3 AU pre-perihelion. Our observations indicate that the emission observed in the OH, OI, CN, NH, and NH2 filters is mostly produced by dissociative electron impact excitation of different parent species. We conclude that CO2 rather than H2O is a significant source of the [OI] 630 nm emission. A strong plume-like feature observed in the in CN and [OI] filters is present throughout our observations. This plume is not present in OH emission and indicates a local enhancement of the CO2/H2O ratio by as much as a factor of 3. We observed a sudden decrease in intensity levels after March 2015, which we attribute to decreased electron temperatures in the first kilometers above the nucleus surface. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.05632v1-abstract-full').style.display = 'none'; document.getElementById('1607.05632v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 figures, 6 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.01253">arXiv:1607.01253</a> <span> [<a href="https://arxiv.org/pdf/1607.01253">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/maps.12703">10.1111/maps.12703 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A plausible link between the asteroid 21 Lutetia and CH carbonaceous chondrites </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Moyano-Cambero%2C+C+E">Carles E. Moyano-Cambero</a>, <a href="/search/?searchtype=author&query=Trigo-Rodr%C3%ADguez%2C+J+M">Josep M. Trigo-Rodr铆guez</a>, <a href="/search/?searchtype=author&query=Llorca%2C+J">Jordi Llorca</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">Maria A. Barucci</a>, <a href="/search/?searchtype=author&query=Rimola%2C+A">Albert Rimola</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1607.01253v1-abstract-short" style="display: inline;"> A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ult… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.01253v1-abstract-full').style.display = 'inline'; document.getElementById('1607.01253v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.01253v1-abstract-full" style="display: none;"> A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ultraviolet to near-infrared (0.3 to 2.2 渭m) and in the mid-infrared to thermal infrared (2.5 to 30.0 渭m or 4000 to ~333 cm^-1), and they are compared here to spectra from the asteroid 21 Lutetia. There are several similarities in absorption bands and overall spectral behavior between this CH3 meteorite and 21 Lutetia. Considering also that the bulk density of Lutetia is similar to that of CH chondrites, we suggest that this asteroid could be similar, or related to, the parent body of these meteorites, if not the parent body itself. However, the apparent surface diversity of Lutetia pointed out in previous studies indicates that it could simultaneously be related to other types of chondrites. Future discovery of additional unweathered CH chondrites could provide deeper insight in the possible connection between this family of metal-rich carbonaceous chondrites and 21 Lutetia or other featureless, possibly hydrated high-albedo asteroids. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.01253v1-abstract-full').style.display = 'none'; document.getElementById('1607.01253v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 7 figures and 2 tables, Meteoritics and Planetary Science, manuscript #2225 (2016)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.02095">arXiv:1605.02095</a> <span> [<a href="https://arxiv.org/pdf/1605.02095">pdf</a>, <a href="https://arxiv.org/ps/1605.02095">ps</a>, <a href="https://arxiv.org/format/1605.02095">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201527784">10.1051/0004-6361/201527784 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Lin%2C+Z">Zhong-Yi Lin</a>, <a href="/search/?searchtype=author&query=Lai%2C+I+-">I. -L. Lai</a>, <a href="/search/?searchtype=author&query=Su%2C+C+-">C. -C. Su</a>, <a href="/search/?searchtype=author&query=Ip%2C+W+-">W. -H. Ip</a>, <a href="/search/?searchtype=author&query=Lee%2C+J+-">J. -C. Lee</a>, <a href="/search/?searchtype=author&query=Wu%2C+J+-">J. -S. Wu</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=La+Forgia%2C+F">F. La Forgia</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debet%2C+S">S. Debet</a> , et al. (26 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1605.02095v1-abstract-short" style="display: inline;"> We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015. We simulated the motion of dust grains ejected from the nucleus surface under the influence of the gravity and viscous drag effect of the expanding gas flow from the rotating… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.02095v1-abstract-full').style.display = 'inline'; document.getElementById('1605.02095v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.02095v1-abstract-full" style="display: none;"> We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015. We simulated the motion of dust grains ejected from the nucleus surface under the influence of the gravity and viscous drag effect of the expanding gas flow from the rotating nucleus. The formation of the curved jet is a combination of the size of the dust particles (~0.1-1 mm) and the location of the source region near the nucleus equator. This enhances the spiral feature of the collimated dust stream after the dust is accelerated to a terminal speed on the order of m/s. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.02095v1-abstract-full').style.display = 'none'; document.getElementById('1605.02095v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.09098">arXiv:1602.09098</a> <span> [<a href="https://arxiv.org/pdf/1602.09098">pdf</a>, <a href="https://arxiv.org/format/1602.09098">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.icarus.2016.02.055">10.1016/j.icarus.2016.02.055 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The global surface composition of 67P/CG nucleus by Rosetta/VIRTIS. I) Prelanding mission phase </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Filacchione%2C+G">Gianrico Filacchione</a>, <a href="/search/?searchtype=author&query=Capaccioni%2C+F">Fabrizio Capaccioni</a>, <a href="/search/?searchtype=author&query=Ciarniello%2C+M">Mauro Ciarniello</a>, <a href="/search/?searchtype=author&query=Raponi%2C+A">Andrea Raponi</a>, <a href="/search/?searchtype=author&query=Tosi%2C+F">Federico Tosi</a>, <a href="/search/?searchtype=author&query=De+Sanctis%2C+M+C">Maria Cristina De Sanctis</a>, <a href="/search/?searchtype=author&query=Erard%2C+S">Stephane Erard</a>, <a href="/search/?searchtype=author&query=Morvan%2C+D+B">Dominique Bockelee Morvan</a>, <a href="/search/?searchtype=author&query=Leyrat%2C+C">Cedric Leyrat</a>, <a href="/search/?searchtype=author&query=Arnold%2C+G">Gabriele Arnold</a>, <a href="/search/?searchtype=author&query=Schmitt%2C+B">Bernard Schmitt</a>, <a href="/search/?searchtype=author&query=Quirico%2C+E">Eric Quirico</a>, <a href="/search/?searchtype=author&query=Piccioni%2C+G">Giuseppe Piccioni</a>, <a href="/search/?searchtype=author&query=Migliorini%2C+A">Alessandra Migliorini</a>, <a href="/search/?searchtype=author&query=Capria%2C+M+T">Maria Teresa Capria</a>, <a href="/search/?searchtype=author&query=Palomba%2C+E">Ernesto Palomba</a>, <a href="/search/?searchtype=author&query=Cerroni%2C+P">Priscilla Cerroni</a>, <a href="/search/?searchtype=author&query=Longobardo%2C+A">Andrea Longobardo</a>, <a href="/search/?searchtype=author&query=Barucci%2C+A">Antonella Barucci</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">Sonia Fornasier</a>, <a href="/search/?searchtype=author&query=Carlson%2C+R+W">Robert W. Carlson</a>, <a href="/search/?searchtype=author&query=Jaumann%2C+R">Ralf Jaumann</a>, <a href="/search/?searchtype=author&query=Stephan%2C+K">Katrin Stephan</a>, <a href="/search/?searchtype=author&query=Moroz%2C+L+V">Lyuba V. Moroz</a>, <a href="/search/?searchtype=author&query=Kappel%2C+D">David Kappel</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.09098v1-abstract-short" style="display: inline;"> From August to November 2014 the Rosetta orbiter has performed an extensive observation campaign aimed at the characterization of 67P/CG nucleus properties and to the selection of the Philae landing site. The campaign led to the production of a global map of the illuminated portion of 67P/CG nucleus. During this prelanding phase the comet's heliocentric distance decreased from 3.62 to 2.93 AU whil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.09098v1-abstract-full').style.display = 'inline'; document.getElementById('1602.09098v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.09098v1-abstract-full" style="display: none;"> From August to November 2014 the Rosetta orbiter has performed an extensive observation campaign aimed at the characterization of 67P/CG nucleus properties and to the selection of the Philae landing site. The campaign led to the production of a global map of the illuminated portion of 67P/CG nucleus. During this prelanding phase the comet's heliocentric distance decreased from 3.62 to 2.93 AU while Rosetta was orbiting around the nucleus at distances between 100 to 10 km. VIRTIS-M, the Visible and InfraRed Thermal Imaging Spectrometer - Mapping channel (Coradini et al. 2007) onboard the orbiter, has acquired 0.25-5.1 micron hyperspectral data of the entire illuminated surface, e.g. the north hemisphere and the equatorial regions, with spatial resolution between 2.5 and 25 m/pixel. I/F spectra have been corrected for thermal emission removal in the 3.5-5.1 micron range and for surface's photometric response. The resulting reflectance spectra have been used to compute several Cometary Spectral Indicators (CSI): single scattering albedo at 0.55 micron, 0.5-0.8 micron and 1.0-2.5 micron spectral slopes, 3.2 micron organic material and 2.0 micron water ice band parameters (center, depth) with the aim to map their spatial distribution on the surface and to study their temporal variability as the nucleus moved towards the Sun. Indeed, throughout the investigated period, the nucleus surface shows a significant increase of the single scattering albedo along with a decrease of the 0.5-0.8 and 1.0-2.5 micron spectral slopes, indicating a flattening of the reflectance. We attribute the origin of this effect to the partial removal of the dust layer caused by the increased contribution of water sublimation to the gaseous activity as comet crossed the frost-line. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.09098v1-abstract-full').style.display = 'none'; document.getElementById('1602.09098v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 Figures, 5 Tables. Accepted for publication in Icarus journal on 29 February 2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.01965">arXiv:1602.01965</a> <span> [<a href="https://arxiv.org/pdf/1602.01965">pdf</a>, <a href="https://arxiv.org/ps/1602.01965">ps</a>, <a href="https://arxiv.org/format/1602.01965">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201527564">10.1051/0004-6361/201527564 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The dust environment of comet 67P/Churyumov-Gerasimenko from Rosetta OSIRIS and VLT observations in the 4.5 to 2.9 au heliocentric distance range inbound </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Moreno%2C+F">F. Moreno</a>, <a href="/search/?searchtype=author&query=Snodgrass%2C+C">C. Snodgrass</a>, <a href="/search/?searchtype=author&query=Hainaut%2C+O">O. Hainaut</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Agarwal%2C+J">J. Agarwal</a>, <a href="/search/?searchtype=author&query=AHearn%2C+M+F">M. F. AHearn</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+L">J. L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=Ferri%2C+F">F. Ferri</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a> , et al. (29 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.01965v1-abstract-short" style="display: inline;"> The ESA Rosetta spacecraft, currently orbiting around comet 67P, has already provided in situ measurements of the dust grain properties from several instruments, particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. To constrain… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01965v1-abstract-full').style.display = 'inline'; document.getElementById('1602.01965v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.01965v1-abstract-full" style="display: none;"> The ESA Rosetta spacecraft, currently orbiting around comet 67P, has already provided in situ measurements of the dust grain properties from several instruments, particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014. A Monte Carlo dust tail code has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is $伪$=--3, instead of $伪$=--2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 au, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 au. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01965v1-abstract-full').style.display = 'none'; document.getElementById('1602.01965v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by Astronomy and Astrophysics (January 17th, 2016)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.05606">arXiv:1601.05606</a> <span> [<a href="https://arxiv.org/pdf/1601.05606">pdf</a>, <a href="https://arxiv.org/ps/1601.05606">ps</a>, <a href="https://arxiv.org/format/1601.05606">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201527675">10.1051/0004-6361/201527675 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The long-wavelength thermal emission of the Pluto-Charon system from Herschel observations. Evidence for emissivity effects </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Lellouch%2C+E">E. Lellouch</a>, <a href="/search/?searchtype=author&query=Santos-Sanz%2C+P">P. Santos-Sanz</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Lim%2C+T">T. Lim</a>, <a href="/search/?searchtype=author&query=Stansberry%2C+J">J. Stansberry</a>, <a href="/search/?searchtype=author&query=Vilenius%2C+E">E. Vilenius</a>, <a href="/search/?searchtype=author&query=Kiss%2C+C">Cs. Kiss</a>, <a href="/search/?searchtype=author&query=M%C3%BCller%2C+T">T. M眉ller</a>, <a href="/search/?searchtype=author&query=Marton%2C+G">G. Marton</a>, <a href="/search/?searchtype=author&query=Protopapa%2C+S">S. Protopapa</a>, <a href="/search/?searchtype=author&query=Panuzzo%2C+P">P. Panuzzo</a>, <a href="/search/?searchtype=author&query=Moreno%2C+R">R. Moreno</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1601.05606v1-abstract-short" style="display: inline;"> Thermal observations of the Pluto-Charon system acquired by the Herschel Space Observatory in February 2012 are presented. They consist of photometric measurements with the PACS and SPIRE instruments (nine visits to the Pluto system each), covering six wavelengths from 70 to 500 $渭$m altogether. The thermal light curve of Pluto-Charon is observed in all filters, albeit more marginally at 160 and e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.05606v1-abstract-full').style.display = 'inline'; document.getElementById('1601.05606v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.05606v1-abstract-full" style="display: none;"> Thermal observations of the Pluto-Charon system acquired by the Herschel Space Observatory in February 2012 are presented. They consist of photometric measurements with the PACS and SPIRE instruments (nine visits to the Pluto system each), covering six wavelengths from 70 to 500 $渭$m altogether. The thermal light curve of Pluto-Charon is observed in all filters, albeit more marginally at 160 and especially 500 $渭$m. Putting these data into the context of older ISO, Spitzer and ground-based observations indicates that the brightness temperature (T$_B$) of the system (rescaled to a common heliocentric distance) drastically decreases with increasing wavelength, from $\sim$53 K at 20 $渭$m to $\sim$35 K at 500 $渭$m, and perhaps ever less at longer wavelengths. Considering a variety of diurnal and/or seasonal thermophysical models, we show that T$_B$ values of 35 K are lower than any expected temperature for the dayside surface or subsurface of Pluto and Charon, implying a low surface emissivity. Based on multiterrain modeling, we infer a spectral emissivity that decreases steadily from 1 at 20-25 $渭$m to $\sim$0.7 at 500~$渭$m. This kind of behavior is usually not observed in asteroids (when proper allowance is made for subsurface sounding), but is found in several icy surfaces of the solar system. We tentatively identify that a combination of a strong dielectric constant and a considerable surface material transparency (typical penetration depth $\sim$1 cm) is responsible for the effect. Our results have implications for the interpretation of the temperature measurements by REX/New Horizons at 4.2 cm wavelength. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.05606v1-abstract-full').style.display = 'none'; document.getElementById('1601.05606v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 9 figures, 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.05277">arXiv:1601.05277</a> <span> [<a href="https://arxiv.org/pdf/1601.05277">pdf</a>, <a href="https://arxiv.org/ps/1601.05277">ps</a>, <a href="https://arxiv.org/format/1601.05277">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.icarus.2016.01.002">10.1016/j.icarus.2016.01.002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spectral variability on primitive asteroids of the Themis and Beagle families: space weathering effects or parent body heterogeneity? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Lantz%2C+C">C. Lantz</a>, <a href="/search/?searchtype=author&query=Perna%2C+D">D. Perna</a>, <a href="/search/?searchtype=author&query=Campins%2C+H">H. Campins</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Nesvorny%2C+D">D. Nesvorny</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1601.05277v1-abstract-short" style="display: inline;"> Themis is an old and statistically robust asteroid family populating the outer main belt, and resulting from a catastrophic collision that took place 2.5$\pm$1.0 Gyr ago. Within the old Themis family a young sub-family, Beagle, formed less than 10 Myr ago, has been identified. We present the results of a spectroscopic survey in the visible and near infrared range of 22 Themis and 8 Beagle families… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.05277v1-abstract-full').style.display = 'inline'; document.getElementById('1601.05277v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.05277v1-abstract-full" style="display: none;"> Themis is an old and statistically robust asteroid family populating the outer main belt, and resulting from a catastrophic collision that took place 2.5$\pm$1.0 Gyr ago. Within the old Themis family a young sub-family, Beagle, formed less than 10 Myr ago, has been identified. We present the results of a spectroscopic survey in the visible and near infrared range of 22 Themis and 8 Beagle families members. The Themis members investigated exhibit a wide range of spectral behaviors, while the younger Beagle family members look spectrally bluer with a smaller spectral slope variability. The best meteorite spectral analogues found for both Themis and Beagle families members are carbonaceous chondrites having experienced different degrees of aqueous alteration, prevalently CM2 but also CV3 and CI, and some of them are chondrite samples being unusual or heated. We extended the spectral analysis including the data available in the literature on Themis and Beagle families members, and we looked for correlations between spectral behavior and physical parameters using the albedo and size values derived from the WISE data. The analysis of this larger sample confirm the spectral diversity within the Themis family and that Beagle members tend to be bluer and to have an higher albedo. The differences between the two family may be partially explained by space weathering processes, which act on these primitive surfaces in a similar way than on S-type asteroids, i.e. producing reddening and darkening. However we see several Themis members having albedos and spectral slopes similar to the young Beagle members. Alternative scenarios are proposed including heterogeneity in the parent body having a compositional gradient with depth, and/or the survival of projectile fragments having a different composition than the parent body. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.05277v1-abstract-full').style.display = 'none'; document.getElementById('1601.05277v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Manuscript pages: 40; Figures: 15 ; Tables: 4 Icarus (2016),in press</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.03193">arXiv:1512.03193</a> <span> [<a href="https://arxiv.org/pdf/1512.03193">pdf</a>, <a href="https://arxiv.org/format/1512.03193">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201527159">10.1051/0004-6361/201527159 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Are fractured cliffs the source of cometary dust jets ? Insights from OSIRIS/Rosetta at 67P </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B. Vincent</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=Pajola%2C+M">M. Pajola</a>, <a href="/search/?searchtype=author&query=H%C3%B6fner%2C+S">S. H枚fner</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Hu%2C+X">X. Hu</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P+L">P. L. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=A%27Hearn%2C+M+F">M. F. A'Hearn</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">D. Bodewits</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. R. El-Maarry</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a> , et al. (30 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1512.03193v2-abstract-short" style="display: inline;"> Dust jets, i.e. fuzzy collimated streams of cometary material arising from the nucleus, have been observed in-situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986. Yet their formation mechanism remains unknown. Several solutions have been proposed, from localized physical mechanisms on the surface/sub-surface (see review in Belton (2010)) to purely dynamical processes involv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.03193v2-abstract-full').style.display = 'inline'; document.getElementById('1512.03193v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.03193v2-abstract-full" style="display: none;"> Dust jets, i.e. fuzzy collimated streams of cometary material arising from the nucleus, have been observed in-situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986. Yet their formation mechanism remains unknown. Several solutions have been proposed, from localized physical mechanisms on the surface/sub-surface (see review in Belton (2010)) to purely dynamical processes involving the focusing of gas flows by the local topography (Crifo et al. 2002). While the latter seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller features (a few meters wide) that connect directly to the nucleus surface. We monitored these jets at high resolution and over several months to understand what are the physical processes driving their formation, and how this affects the surface. Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets, and linked them precisely to their sources on the nucleus. Results.We show here observational evidence that the Northern hemisphere jets of comet 67P arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features, and therefore the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.03193v2-abstract-full').style.display = 'none'; document.getElementById('1512.03193v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by Astronomy & Astrophysics on 4 December 2015</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 587, A14 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.02794">arXiv:1509.02794</a> <span> [<a href="https://arxiv.org/pdf/1509.02794">pdf</a>, <a href="https://arxiv.org/format/1509.02794">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201527020">10.1051/0004-6361/201527020 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Groussin%2C+O">O. Groussin</a>, <a href="/search/?searchtype=author&query=Sierks%2C+H">H. Sierks</a>, <a href="/search/?searchtype=author&query=Barbieri%2C+C">C. Barbieri</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P">P. Lamy</a>, <a href="/search/?searchtype=author&query=Rodrigo%2C+R">R. Rodrigo</a>, <a href="/search/?searchtype=author&query=Koschny%2C+D">D. Koschny</a>, <a href="/search/?searchtype=author&query=Rickman%2C+H">H. Rickman</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">H. U. Keller</a>, <a href="/search/?searchtype=author&query=Hearn%2C+M+F+A">M. F. A Hearn</a>, <a href="/search/?searchtype=author&query=Auger%2C+A+-">A. -T. Auger</a>, <a href="/search/?searchtype=author&query=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Bertaux%2C+J+-">J. -L. Bertaux</a>, <a href="/search/?searchtype=author&query=Bertini%2C+I">I. Bertini</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Cremonese%2C+G">G. Cremonese</a>, <a href="/search/?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">B. Davidsson</a>, <a href="/search/?searchtype=author&query=Debei%2C+S">S. Debei</a>, <a href="/search/?searchtype=author&query=De+Cecco%2C+M">M. De Cecco</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+M+R">M. R. El-Maarry</a>, <a href="/search/?searchtype=author&query=Fornasier%2C+S">S. Fornasier</a>, <a href="/search/?searchtype=author&query=Fulle%2C+M">M. Fulle</a>, <a href="/search/?searchtype=author&query=Guti%C3%A9rrez%2C+P+J">P. J. Guti茅rrez</a>, <a href="/search/?searchtype=author&query=G%C3%BCttler%2C+C">C. G眉ttler</a>, <a href="/search/?searchtype=author&query=Hviid%2C+S">S. Hviid</a> , et al. (23 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1509.02794v1-abstract-short" style="display: inline;"> We report on the first major temporal morphological changes observed on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, in the smooth terrains of the Imhotep region. We use images of the OSIRIS cameras onboard Rosetta to follow the temporal changes from 24 May 2015 to 11 July 2015. The morphological changes observed on the surface are visible in the form of roundish features, which… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02794v1-abstract-full').style.display = 'inline'; document.getElementById('1509.02794v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.02794v1-abstract-full" style="display: none;"> We report on the first major temporal morphological changes observed on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, in the smooth terrains of the Imhotep region. We use images of the OSIRIS cameras onboard Rosetta to follow the temporal changes from 24 May 2015 to 11 July 2015. The morphological changes observed on the surface are visible in the form of roundish features, which are growing in size from a given location in a preferential direction, at a rate of 5.6 - 8.1$\times$10$^{-5}$ m s$^{-1}$ during the observational period. The location where changes started and the contours of the expanding features are bluer than the surroundings, suggesting the presence of ices (H$_2$O and/or CO$_2$) exposed on the surface. However, sublimation of ices alone is not sufficient to explain the observed expanding features. No significant variations in the dust activity pattern are observed during the period of changes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02794v1-abstract-full').style.display = 'none'; document.getElementById('1509.02794v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 3 figures; Letter for Astronomy and Astrophysics: accepted</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 583, A36 (2015) </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" 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