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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/1909.03853">arXiv:1909.03853</a> <span> [<a href="https://arxiv.org/pdf/1909.03853">pdf</a>, <a href="https://arxiv.org/format/1909.03853">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/10.1029/2019GL083982">10.1029/2019GL083982 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Migrating Scarps as a Significant Driver for Cometary Surface Evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Birch%2C+S">Samuel Birch</a>, <a href="/search/?searchtype=author&query=Hayes%2C+A">Alexander Hayes</a>, <a href="/search/?searchtype=author&query=Umurhan%2C+O">Orkan Umurhan</a>, <a href="/search/?searchtype=author&query=Tang%2C+Y">Yuhui Tang</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J">Jean-Baptiste Vincent</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">Nilda Oklay</a>, <a href="/search/?searchtype=author&query=Bodewits%2C+D">Dennis Bodewits</a>, <a href="/search/?searchtype=author&query=Davidsson%2C+B">Bjorn Davidsson</a>, <a href="/search/?searchtype=author&query=Marschall%2C+R">Raphael Marschall</a>, <a href="/search/?searchtype=author&query=Soderblom%2C+J">Jason Soderblom</a>, <a href="/search/?searchtype=author&query=Moore%2C+J">Jeff Moore</a>, <a href="/search/?searchtype=author&query=Corlies%2C+P">Paul Corlies</a>, <a href="/search/?searchtype=author&query=Squyres%2C+S">Steven Squyres</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="1909.03853v1-abstract-short" style="display: inline;"> Rosetta observations of 67P/Churyumov-Gerasimenko (67P) reveal that most changes occur in the fallback-generated smooth terrains, vast deposits of granular material blanketing the comet's northern hemisphere. These changes express themselves both morphologically and spectrally across the nucleus, yet we lack a model that describes their formation and evolution. Here we present a self-consistent mo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.03853v1-abstract-full').style.display = 'inline'; document.getElementById('1909.03853v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.03853v1-abstract-full" style="display: none;"> Rosetta observations of 67P/Churyumov-Gerasimenko (67P) reveal that most changes occur in the fallback-generated smooth terrains, vast deposits of granular material blanketing the comet's northern hemisphere. These changes express themselves both morphologically and spectrally across the nucleus, yet we lack a model that describes their formation and evolution. Here we present a self-consistent model that thoroughly explains the activity and mass loss from Hapi's smooth terrains. Our model predicts the removal of dust via re-radiated solar insolation localized within depression scarps that are substantially more ice-rich than previously expected. We couple our model with numerous Rosetta observations to thoroughly capture the seasonal erosion of Hapi's smooth terrains, where local scarp retreat gradually removes the uppermost dusty mantle. As sublimation-regolith interactions occur on rocky planets, comets, icy moons and KBOs, our coupled model and observations provide a foundation for future understanding of the myriad of sublimation-carved worlds. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.03853v1-abstract-full').style.display = 'none'; document.getElementById('1909.03853v1-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">14 pages, 4 figures, accepted GRL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.05607">arXiv:1904.05607</a> <span> [<a href="https://arxiv.org/pdf/1904.05607">pdf</a>, <a href="https://arxiv.org/format/1904.05607">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/10.1007/s11214-019-0596-8">10.1007/s11214-019-0596-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Local manifestations of cometary activity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Vincent%2C+J">Jean-Baptiste Vincent</a>, <a href="/search/?searchtype=author&query=Farnham%2C+T">Tony Farnham</a>, <a href="/search/?searchtype=author&query=K%C3%BChrt%2C+E">Ekkehard K眉hrt</a>, <a href="/search/?searchtype=author&query=Skorov%2C+Y">Yuri Skorov</a>, <a href="/search/?searchtype=author&query=Marschall%2C+R">Raphael Marschall</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">Nilda Oklay</a>, <a href="/search/?searchtype=author&query=El-Maarry%2C+R">Ramy El-Maarry</a>, <a href="/search/?searchtype=author&query=Keller%2C+H+U">Horst Uwe Keller</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="1904.05607v1-abstract-short" style="display: inline;"> Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity. Although the basic principles are well established, most details remain elusive, especially regarding the mechanisms by which dust is detached from the surface and sub… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.05607v1-abstract-full').style.display = 'inline'; document.getElementById('1904.05607v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.05607v1-abstract-full" style="display: none;"> Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity. Although the basic principles are well established, most details remain elusive, especially regarding the mechanisms by which dust is detached from the surface and subsequently accelerated by the gas flows surrounding the nucleus. During its 2 years rendez-vous with comet 67P/Churyumov-Gerasimenko, ESA's Rosetta has observed cometary activity with unprecedented details, in both the inbound and outbound legs of the comet's orbit. This trove of data provides a solid ground on which new models of activity can be built. In this chapter, we review how activity manifests at close distance from the surface, establish a nomenclature for the different types of observed features, discuss how activity is at the same time transforming and being shaped by the topography, and finally address several potential mechanisms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.05607v1-abstract-full').style.display = 'none'; document.getElementById('1904.05607v1-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 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">This paper is a review chapter in the upcoming book "Comets: Post 67P Perspectives" edited by ISSI and Space Science Reviews. Accepted on 08 April 2019</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/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/1705.03740">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/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/1602.01965">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/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> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.02707">arXiv:1509.02707</a> <span> [<a href="https://arxiv.org/pdf/1509.02707">pdf</a>, <a href="https://arxiv.org/format/1509.02707">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/10.1051/0004-6361/201526379">10.1051/0004-6361/201526379 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitational slopes, geomorphology, and material strengths 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=Groussin%2C+O">O. Groussin</a>, <a href="/search/?searchtype=author&query=Jorda%2C+L">L. Jorda</a>, <a href="/search/?searchtype=author&query=Auger%2C+A+-">A. -T. Auger</a>, <a href="/search/?searchtype=author&query=K%C3%BChrt%2C+E">E. K眉hrt</a>, <a href="/search/?searchtype=author&query=Gaskell%2C+R">R. Gaskell</a>, <a href="/search/?searchtype=author&query=Capanna%2C+C">C. Capanna</a>, <a href="/search/?searchtype=author&query=Scholten%2C+F">F. Scholten</a>, <a href="/search/?searchtype=author&query=Preusker%2C+F">F. Preusker</a>, <a href="/search/?searchtype=author&query=Lamy%2C+P">P. Lamy</a>, <a href="/search/?searchtype=author&query=Hviid%2C+S">S. Hviid</a>, <a href="/search/?searchtype=author&query=Knollenberg%2C+J">J. Knollenberg</a>, <a href="/search/?searchtype=author&query=Keller%2C+U">U. Keller</a>, <a href="/search/?searchtype=author&query=Huettig%2C+C">C. Huettig</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=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=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=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> , et al. (27 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="1509.02707v1-abstract-short" style="display: inline;"> We study the link between gravitational slopes and the surface morphology on the nucleus of comet 67P/Churyumov-Gerasimenko and provide constraints on the mechanical properties of the cometary material. We computed the gravitational slopes for five regions on the nucleus that are representative of the different morphologies observed on the surface, using two shape models computed from OSIRIS image… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02707v1-abstract-full').style.display = 'inline'; document.getElementById('1509.02707v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.02707v1-abstract-full" style="display: none;"> We study the link between gravitational slopes and the surface morphology on the nucleus of comet 67P/Churyumov-Gerasimenko and provide constraints on the mechanical properties of the cometary material. We computed the gravitational slopes for five regions on the nucleus that are representative of the different morphologies observed on the surface, using two shape models computed from OSIRIS images by the stereo-photoclinometry (SPC) and stereo-photogrammetry (SPG) techniques. We estimated the tensile, shear, and compressive strengths using different surface morphologies and mechanical considerations. The different regions show a similar general pattern in terms of the relation between gravitational slopes and terrain morphology: i) low-slope terrains (0-20 deg) are covered by a fine material and contain a few large ($>$10 m) and isolated boulders, ii) intermediate-slope terrains (20-45 deg) are mainly fallen consolidated materials and debris fields, with numerous intermediate-size boulders from $<$1 m to 10 m for the majority of them, and iii) high-slope terrains (45-90 deg) are cliffs that expose a consolidated material and do not show boulders or fine materials. The best range for the tensile strength of overhangs is 3-15 Pa (upper limit of 150 Pa), 4-30 Pa for the shear strength of fine surface materials and boulders, and 30-150 Pa for the compressive strength of overhangs (upper limit of 1500 Pa). The strength-to-gravity ratio is similar for 67P and weak rocks on Earth. As a result of the low compressive strength, the interior of the nucleus may have been compressed sufficiently to initiate diagenesis, which could have contributed to the formation of layers. Our value for the tensile strength is comparable to that of dust aggregates formed by gravitational instability and tends to favor a formation of comets by the accrection of pebbles at low velocities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02707v1-abstract-full').style.display = 'none'; document.getElementById('1509.02707v1-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">18 pages, 15 figures, 1 table; Astronomy and Astrophysics, 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/1505.06888">arXiv:1505.06888</a> <span> [<a href="https://arxiv.org/pdf/1505.06888">pdf</a>, <a href="https://arxiv.org/ps/1505.06888">ps</a>, <a href="https://arxiv.org/format/1505.06888">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/10.1051/0004-6361/201525901">10.1051/0004-6361/201525901 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from the OSIRIS instrument onboard the ROSETTA spacecraft </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=Barucci%2C+M+A">M. A. Barucci</a>, <a href="/search/?searchtype=author&query=Feller%2C+C">C. Feller</a>, <a href="/search/?searchtype=author&query=Besse%2C+S">S. Besse</a>, <a href="/search/?searchtype=author&query=Leyrat%2C+C">C. Leyrat</a>, <a href="/search/?searchtype=author&query=Lara%2C+L">L. Lara</a>, <a href="/search/?searchtype=author&query=Gutierrez%2C+P+J">P. J. Gutierrez</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=Tubiana%2C+C">C. Tubiana</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+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=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> , 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="1505.06888v1-abstract-short" style="display: inline;"> The Rosetta mission of the European Space Agency has been orbiting the comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted are onboard Rosetta. We present results for the photometric and spectrophotometric properties of the nucleus of 67P derived f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1505.06888v1-abstract-full').style.display = 'inline'; document.getElementById('1505.06888v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1505.06888v1-abstract-full" style="display: none;"> The Rosetta mission of the European Space Agency has been orbiting the comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted are onboard Rosetta. We present results for the photometric and spectrophotometric properties of the nucleus of 67P derived from the OSIRIS imaging system, which consists of a Wide Angle Camera (WAC) and a Narrow Angle Camera (NAC). The disk-averaged phase function of the nucleus of 67P shows a strong opposition surge with a G parameter value of -0.13$\pm$0.01 in the HG system formalism and an absolute magnitude $H_v(1,1,0)$ = 15.74$\pm$0.02 mag. The integrated spectrophotometry in 20 filters covering the 250-1000 nm wavelength range shows a red spectral behavior, without clear absorption bands except for a potential absorption centered at $\sim$ 290 nm that is possibly due to SO$_2$ ice. The nucleus shows strong phase reddening, with disk-averaged spectral slopes increasing from 11\%/(100 nm) to 16\%/(100 nm) in the 1.3$^{\circ}$--54$^{\circ}$ phase angle range. The geometric albedo of the comet is 6.5$\pm$0.2\% at 649 nm, with local variations of up to $\sim$ 16\% in the Hapi region. From the disk-resolved images we computed the spectral slope together with local spectrophotometry and identified three distinct groups of regions (blue, moderately red, and red). The Hapi region is the brightest, the bluest in term of spectral slope, and the most active surface on the comet. Local spectrophotometry shows an enhancement of the flux in the 700-750 nm that is associated with coma emissions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1505.06888v1-abstract-full').style.display = 'none'; document.getElementById('1505.06888v1-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 May, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">18, pages, 14 figures, Astronomy and Astrophysics, 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 583, A30 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1401.6152">arXiv:1401.6152</a> <span> [<a href="https://arxiv.org/pdf/1401.6152">pdf</a>, <a href="https://arxiv.org/format/1401.6152">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.2014.02.021">10.1016/j.icarus.2014.02.021 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The contamination of the surface of Vesta by impacts and the delivery of the dark material </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Turrini%2C+D">D. Turrini</a>, <a href="/search/?searchtype=author&query=Combe%2C+J+-">J. -P. Combe</a>, <a href="/search/?searchtype=author&query=McCord%2C+T+B">T. B. McCord</a>, <a href="/search/?searchtype=author&query=Oklay%2C+N">N. Oklay</a>, <a href="/search/?searchtype=author&query=Vincent%2C+J+-">J. -B Vincent</a>, <a href="/search/?searchtype=author&query=Prettyman%2C+T+H">T. H. Prettyman</a>, <a href="/search/?searchtype=author&query=McSween%2C+H+Y">H. Y. McSween</a>, <a href="/search/?searchtype=author&query=SJ%2C+G+J+C">G. J. Consolmagno SJ</a>, <a href="/search/?searchtype=author&query=De+Sanctis%2C+M+C">M. C. De Sanctis</a>, <a href="/search/?searchtype=author&query=Corre%2C+L+L">L. Le Corre</a>, <a href="/search/?searchtype=author&query=Longobardo%2C+A">A. Longobardo</a>, <a href="/search/?searchtype=author&query=Palomba%2C+E">E. Palomba</a>, <a href="/search/?searchtype=author&query=Russell%2C+C+T">C. T. Russell</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="1401.6152v3-abstract-short" style="display: inline;"> The Dawn spacecraft observed the presence of dark material, which in turn proved to be associated with OH and H-rich material, on the surface of Vesta. The source of this dark material has been identified with the low albedo asteroids, but it is still a matter of debate whether the delivery of the dark material is associated with a few large impact events, to micrometeorites or to the continuous,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.6152v3-abstract-full').style.display = 'inline'; document.getElementById('1401.6152v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1401.6152v3-abstract-full" style="display: none;"> The Dawn spacecraft observed the presence of dark material, which in turn proved to be associated with OH and H-rich material, on the surface of Vesta. The source of this dark material has been identified with the low albedo asteroids, but it is still a matter of debate whether the delivery of the dark material is associated with a few large impact events, to micrometeorites or to the continuous, secular flux of impactors on Vesta. The continuous flux scenario predicts that a significant fraction of the exogenous material accreted by Vesta should be due to non-dark impactors likely analogous to ordinary chondrites, which instead represent only a minor contaminant in the HED meteorites. We explored the continuous flux scenario and its implications for the composition of the vestan regolith, taking advantage of the data from the Dawn mission and the HED meteorites. We used our model to show that the stochastic events scenario and the micrometeoritic flux scenario are natural consequences of the continuous flux scenario. We then used the model to estimate the amounts of dark and hydroxylate materials delivered on Vesta since the LHB and we showed how our results match well with the values estimated by the Dawn mission. We used our model to assess the amount of Fe and siderophile elements that the continuous flux of impactors would mix in the vestan regolith: concerning the siderophile elements, we focused our attention on the role of Ni. The results are in agreement with the data available on the Fe and Ni content of the HED meteorites and can be used as a reference frame in future studies of the data from the Dawn mission and of the HED meteorites. Our model cannot yet provide an answer to the fate of the missing non-carbonaceous contaminants, but we discuss possible reasons for this discrepancy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.6152v3-abstract-full').style.display = 'none'; document.getElementById('1401.6152v3-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 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2014. </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">31 pages, 7 figures, 4 tables. Accepted for publication on the journal ICARUS, "Dark and Bright Materials on Vesta" special issue</span> </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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