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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.05469">arXiv:2410.05469</a> <span> [<a href="https://arxiv.org/pdf/2410.05469">pdf</a>, <a href="https://arxiv.org/format/2410.05469">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> JWST/MIRI detection of [Ne V], [Ne VI], and [O IV] wind emission in the O9V star 10 Lacertae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Law%2C+D+R">David R. Law</a>, <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">Calum Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+L+J">Linda J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">Christopher J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Gordon%2C+K+D">Karl D. Gordon</a>, <a href="/search/astro-ph?searchtype=author&query=Kumari%2C+N">Nimisha Kumari</a>, <a href="/search/astro-ph?searchtype=author&query=Leitherer%2C+C">Claus Leitherer</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="2410.05469v3-abstract-short" style="display: inline;"> We report the detection of broad, flat-topped emission in the fine-structure lines of [Ne V], [Ne VI], and [O IV] in mid-infrared spectra of the O9 V star 10 Lacertae obtained with JWST/MIRI. Optically thin emission in these high ions traces a hot, low-density component of the wind. The observed line fluxes imply a mass-loss rate of > 3 x 10^8 Msun/yr, which is an order of magnitude larger than pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05469v3-abstract-full').style.display = 'inline'; document.getElementById('2410.05469v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.05469v3-abstract-full" style="display: none;"> We report the detection of broad, flat-topped emission in the fine-structure lines of [Ne V], [Ne VI], and [O IV] in mid-infrared spectra of the O9 V star 10 Lacertae obtained with JWST/MIRI. Optically thin emission in these high ions traces a hot, low-density component of the wind. The observed line fluxes imply a mass-loss rate of > 3 x 10^8 Msun/yr, which is an order of magnitude larger than previous estimates based on UV and optical diagnostics. The presence of this hot component reconciles measured values of the mass-loss rate with theoretical predictions, and appears to solve the "weak wind" problem for the particular case of 10 Lac. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05469v3-abstract-full').style.display = 'none'; document.getElementById('2410.05469v3-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 5, figures, ApJL 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/2405.00085">arXiv:2405.00085</a> <span> [<a href="https://arxiv.org/pdf/2405.00085">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive Stars at Low Metallicity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">Jorick S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P">Paul Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">Miriam Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">Fabrice Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Morrell%2C+N">Nidia Morrell</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L">Lida Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Louis%2C+N+S">Nicole St. Louis</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">Asif ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A">Andreas Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">Hugues Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J">Jean-Claude Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Kubatova%2C+B">Brankica Kubatova</a>, <a href="/search/astro-ph?searchtype=author&query=Marchant%2C+P">Pablo Marchant</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+L+P">Lucimara P. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Wofford%2C+A">Aida Wofford</a>, <a href="/search/astro-ph?searchtype=author&query=van+Loon%2C+J">Jacco van Loon</a>, <a href="/search/astro-ph?searchtype=author&query=Telford%2C+O+G">O. Grace Telford</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B6tberg%2C+Y">Ylva G枚tberg</a>, <a href="/search/astro-ph?searchtype=author&query=Bowman%2C+D">Dominic Bowman</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">Christi Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Kalari%2C+V">Venu Kalari</a>, <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+T+X">The XShootU Collaboration</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.00085v1-abstract-short" style="display: inline;"> The Hubble Space Telescope has devoted 500 orbits to observing 250 massive stars with low metallicity in the ultraviolet (UV) range within the framework of the ULLYSES program. The X-Shooting ULLYSES (XShootU) project enhances the legacy value of this UV dataset by providing high-quality optical and near-infrared spectra, which are acquired using the wide-wavelength-coverage X-shooter spectrograph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00085v1-abstract-full').style.display = 'inline'; document.getElementById('2405.00085v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.00085v1-abstract-full" style="display: none;"> The Hubble Space Telescope has devoted 500 orbits to observing 250 massive stars with low metallicity in the ultraviolet (UV) range within the framework of the ULLYSES program. The X-Shooting ULLYSES (XShootU) project enhances the legacy value of this UV dataset by providing high-quality optical and near-infrared spectra, which are acquired using the wide-wavelength-coverage X-shooter spectrograph at ESO's Very Large Telescope. XShootU emphasises the importance of combining UV with optical spectra for the consistent determination of key stellar parameters such as effective temperature, surface gravity, luminosity, abundances, and wind characteristics including mass-loss rates as a function of metallicity. Since uncertainties in these parameters have implications across various branches of astrophysics, the data and modelling generated by the XShootU project are poised to significantly advance our understanding of massive stars at low metallicity. This is particularly crucial for confidently interpreting JWST data of the earliest stellar generations, making XShootU a unique resource for comprehending individual spectra of low-metallicity stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00085v1-abstract-full').style.display = 'none'; document.getElementById('2405.00085v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 6 figures. ESO Large Programme Overview</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ESO Messenger, 2024 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.01240">arXiv:2401.01240</a> <span> [<a href="https://arxiv.org/pdf/2401.01240">pdf</a>, <a href="https://arxiv.org/format/2401.01240">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</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/stad3966">10.1093/mnras/stad3966 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optically-thick Structure in Early B Type Supergiant Stellar Winds at Low Metallicities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Parsons%2C+T+N">Timothy N. Parsons</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">Raman K. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Bernini-Peron%2C+M">Matheus Bernini-Peron</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alex W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D+L">Derck L. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L+M">Lidia M. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Pauli%2C+D">Daniel Pauli</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">Andreas A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Rickard%2C+M+J">Matthew J. Rickard</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="2401.01240v1-abstract-short" style="display: inline;"> Accurate determination of mass-loss rates from massive stars is important to understanding stellar and galactic evolution and enrichment of the interstellar medium. Large-scale structure and variability in stellar winds have significant effects on mass-loss rates. Time-series observations provide direct quantification of such variability. Observations of this nature are available for some Galactic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01240v1-abstract-full').style.display = 'inline'; document.getElementById('2401.01240v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01240v1-abstract-full" style="display: none;"> Accurate determination of mass-loss rates from massive stars is important to understanding stellar and galactic evolution and enrichment of the interstellar medium. Large-scale structure and variability in stellar winds have significant effects on mass-loss rates. Time-series observations provide direct quantification of such variability. Observations of this nature are available for some Galactic early supergiant stars but not yet for stars in lower metallicity environments such as the Magellanic Clouds. We utilise ultraviolet spectra from the Hubble Space Telescope ULLYSES program to demonstrate that the presence of structure in stellar winds of supergiant stars at low metallicities may be discerned from single-epoch spectra. We find evidence that, for given stellar luminosities and mean stellar wind optical depths, structure is more prevalent at higher metallicities. We confirm, at Large Magellanic Cloud (0.5 Z_solar), Small Magellanic Cloud (0.2 Z_solar) and lower (0.14 -- 0.1 Z_solar) metallicities, earlier Galactic results that there does not appear to be correlation between the degree of structure in stellar winds of massive stars and stellar effective temperature. Similar lack of correlation is found with regard to terminal velocity of stellar winds. Additional and revised values for radial velocities of stars and terminal velocities of stellar winds are presented. Direct evidence of temporal variability, on timescales of several days, in stellar wind at low metallicity is found. We illustrate that narrow absorption components in wind-formed profiles of Galactic OB stellar spectra remain common in early B supergiant spectra at low metallicities, providing means for better constraining hot, massive star mass-loss rates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01240v1-abstract-full').style.display = 'none'; document.getElementById('2401.01240v1-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages plus Appendices, 9 figures plus 37 figures in Appendices. Accepted by 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/2306.04572">arXiv:2306.04572</a> <span> [<a href="https://arxiv.org/pdf/2306.04572">pdf</a>, <a href="https://arxiv.org/format/2306.04572">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/10.1088/1538-3873/acd7a3">10.1088/1538-3873/acd7a3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Near Infrared Imager and Slitless Spectrograph for the James Webb Space Telescope -- III. Single Object Slitless Spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Albert%2C+L">Loic Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Lafreniere%2C+D">David Lafreniere</a>, <a href="/search/astro-ph?searchtype=author&query=Doyon%2C+R">Rene Doyon</a>, <a href="/search/astro-ph?searchtype=author&query=Artigau%2C+E">Etienne Artigau</a>, <a href="/search/astro-ph?searchtype=author&query=Volk%2C+K">Kevin Volk</a>, <a href="/search/astro-ph?searchtype=author&query=Goudfrooij%2C+P">Paul Goudfrooij</a>, <a href="/search/astro-ph?searchtype=author&query=Martel%2C+A+R">Andre R. Martel</a>, <a href="/search/astro-ph?searchtype=author&query=Radica%2C+M">Michael Radica</a>, <a href="/search/astro-ph?searchtype=author&query=Rowe%2C+J">Jason Rowe</a>, <a href="/search/astro-ph?searchtype=author&query=Espinoza%2C+N">Nestor Espinoza</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+A">Arpita Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Filippazzo%2C+J+C">Joseph C. Filippazzo</a>, <a href="/search/astro-ph?searchtype=author&query=Darveau-Bernier%2C+A">Antoine Darveau-Bernier</a>, <a href="/search/astro-ph?searchtype=author&query=Talens%2C+G+J">Geert Jan Talens</a>, <a href="/search/astro-ph?searchtype=author&query=Sivaramakrishnan%2C+A">Anand Sivaramakrishnan</a>, <a href="/search/astro-ph?searchtype=author&query=Willott%2C+C+J">Chris J. Willott</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=LaMassa%2C+S">Stephanie LaMassa</a>, <a href="/search/astro-ph?searchtype=author&query=Hutchings%2C+J+B">John B. Hutchings</a>, <a href="/search/astro-ph?searchtype=author&query=Rowlands%2C+N">Neil Rowlands</a>, <a href="/search/astro-ph?searchtype=author&query=Vila%2C+M+B">M. Begona Vila</a>, <a href="/search/astro-ph?searchtype=author&query=Zhou%2C+J">Julia Zhou</a>, <a href="/search/astro-ph?searchtype=author&query=Aldridge%2C+D">David Aldridge</a>, <a href="/search/astro-ph?searchtype=author&query=Maszkiewicz%2C+M">Michael Maszkiewicz</a>, <a href="/search/astro-ph?searchtype=author&query=Beaulieu%2C+M">Mathilde Beaulieu</a> , et al. (15 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.04572v1-abstract-short" style="display: inline;"> The Near Infrared Imager and Slitless Spectrograph instrument (NIRISS) is the Canadian Space Agency (CSA) contribution to the suite of four science instruments of JWST. As one of the three NIRISS observing modes, the Single Object Slitless Spectroscopy (SOSS) mode is tailor-made to undertake time-series observations of exoplanets to perform transit spectroscopy. The SOSS permits observing point so… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04572v1-abstract-full').style.display = 'inline'; document.getElementById('2306.04572v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.04572v1-abstract-full" style="display: none;"> The Near Infrared Imager and Slitless Spectrograph instrument (NIRISS) is the Canadian Space Agency (CSA) contribution to the suite of four science instruments of JWST. As one of the three NIRISS observing modes, the Single Object Slitless Spectroscopy (SOSS) mode is tailor-made to undertake time-series observations of exoplanets to perform transit spectroscopy. The SOSS permits observing point sources between 0.6 and 2.8 um at a resolving power of 650 at 1.25 um using a slit-less cross-dispersing grism while its defocussing cylindrical lens enables observing targets as bright as J=6.7 by spreading light across 23 pixels along the cross-dispersion axis. This paper officially presents the design of the SOSS mode, its operation, characterization, and its performance, from ground-based testing and flight-based Commissioning. On-sky measurements demonstrate a peak photon conversion efficiency of 55% at 1.2 um. The first time-series on the A-type star BD+60o1753 achieves a flux stability close to the photon-noise limit, so far tested to a level of 20 parts per million on 40-minute time-scales after simply subtracting a long-term trend. Uncorrected 1/f noise residuals underneath the spectral traces add an extra source of noise equivalent to doubling the readout noise. Preliminary analysis of a HAT-P-14b transit time-series indicates that it is difficult to remove all the noise in pixels with partially saturated ramps. Overall, the SOSS delivers performance at the level required to tackle key exoplanet science programs such as detecting secondary atmospheres on terrestrial planets and measuring abundances of several chemical species in gas giants. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04572v1-abstract-full').style.display = 'none'; document.getElementById('2306.04572v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">41 pages, 28 figures, accepted for publication in PASP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.03277">arXiv:2306.03277</a> <span> [<a href="https://arxiv.org/pdf/2306.03277">pdf</a>, <a href="https://arxiv.org/format/2306.03277">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> The Near Infrared Imager and Slitless Spectrograph for the James Webb Space Telescope -- I. Instrument Overview and in-Flight Performance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Doyon%2C+R">Rene Doyon</a>, <a href="/search/astro-ph?searchtype=author&query=Willott%2C+C+J">C. J Willott</a>, <a href="/search/astro-ph?searchtype=author&query=Hutchings%2C+J+B">John B. Hutchings</a>, <a href="/search/astro-ph?searchtype=author&query=Sivaramakrishnan%2C+A">Anand Sivaramakrishnan</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+L">Loic Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Lafreniere%2C+D">David Lafreniere</a>, <a href="/search/astro-ph?searchtype=author&query=Rowlands%2C+N">Neil Rowlands</a>, <a href="/search/astro-ph?searchtype=author&query=Vila%2C+M+B">M. Begona Vila</a>, <a href="/search/astro-ph?searchtype=author&query=Martel%2C+A+R">Andre R. Martel</a>, <a href="/search/astro-ph?searchtype=author&query=LaMassa%2C+S">Stephanie LaMassa</a>, <a href="/search/astro-ph?searchtype=author&query=Aldridge%2C+D">David Aldridge</a>, <a href="/search/astro-ph?searchtype=author&query=Artigau%2C+E">Etienne Artigau</a>, <a href="/search/astro-ph?searchtype=author&query=Cameron%2C+P">Peter Cameron</a>, <a href="/search/astro-ph?searchtype=author&query=Chayer%2C+P">Pierre Chayer</a>, <a href="/search/astro-ph?searchtype=author&query=Cook%2C+N+J">Neil J. Cook</a>, <a href="/search/astro-ph?searchtype=author&query=Cooper%2C+R+A">Rachel A. Cooper</a>, <a href="/search/astro-ph?searchtype=author&query=Darveau-Bernier%2C+A">Antoine Darveau-Bernier</a>, <a href="/search/astro-ph?searchtype=author&query=Dupuis%2C+J">Jean Dupuis</a>, <a href="/search/astro-ph?searchtype=author&query=Earnshaw%2C+C">Colin Earnshaw</a>, <a href="/search/astro-ph?searchtype=author&query=Espinoza%2C+N">Nestor Espinoza</a>, <a href="/search/astro-ph?searchtype=author&query=Filippazzo%2C+J+C">Joseph C. Filippazzo</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gaudreau%2C+D">Daniel Gaudreau</a>, <a href="/search/astro-ph?searchtype=author&query=Gawlik%2C+R">Roman Gawlik</a>, <a href="/search/astro-ph?searchtype=author&query=Goudfrooij%2C+P">Paul Goudfrooij</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="2306.03277v1-abstract-short" style="display: inline;"> The Near-Infrared Imager and Slitless Spectrograph (NIRISS) is the science module of the Canadian-built Fine Guidance Sensor (FGS) onboard the James Webb Space Telescope (JWST). NIRISS has four observing modes: 1) broadband imaging featuring seven of the eight NIRCam broadband filters, 2) wide-field slitless spectroscopy (WFSS) at a resolving power of $\sim$150 between 0.8 and 2.2 $渭$m, 3) single-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.03277v1-abstract-full').style.display = 'inline'; document.getElementById('2306.03277v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.03277v1-abstract-full" style="display: none;"> The Near-Infrared Imager and Slitless Spectrograph (NIRISS) is the science module of the Canadian-built Fine Guidance Sensor (FGS) onboard the James Webb Space Telescope (JWST). NIRISS has four observing modes: 1) broadband imaging featuring seven of the eight NIRCam broadband filters, 2) wide-field slitless spectroscopy (WFSS) at a resolving power of $\sim$150 between 0.8 and 2.2 $渭$m, 3) single-object cross-dispersed slitless spectroscopy (SOSS) enabling simultaneous wavelength coverage between 0.6 and 2.8 $渭$m at R$\sim$700, a mode optimized for exoplanet spectroscopy of relatively bright ($J<6.3$) stars and 4) aperture masking interferometry (AMI) between 2.8 and 4.8 $渭$m enabling high-contrast ($\sim10^{-3}-10^{-4}$) imaging at angular separations between 70 and 400 milliarcsec for relatively bright ($M<8$) sources. This paper presents an overview of the NIRISS instrument, its design, its scientific capabilities, and a summary of in-flight performance. NIRISS shows significantly better response shortward of $\sim2.5\,渭$m resulting in 10-40% sensitivity improvement for broadband and low-resolution spectroscopy compared to pre-flight predictions. Two time-series observations performed during instrument commissioning in the SOSS mode yield very stable spectro-photometry performance within $\sim$10% of the expected noise. The first space-based companion detection of the tight binary star AB Dor AC through AMI was demonstrated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.03277v1-abstract-full').style.display = 'none'; document.getElementById('2306.03277v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.06376">arXiv:2305.06376</a> <span> [<a href="https://arxiv.org/pdf/2305.06376">pdf</a>, <a href="https://arxiv.org/format/2305.06376">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</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/10.1051/0004-6361/202245650">10.1051/0004-6361/202245650 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: massive stars at low metallicity. I. Project Description </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">Jorick S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Mehner%2C+A">A. Mehner</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Morrell%2C+N">N. Morrell</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L+M">L. M. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=St-Louis%2C+N">N. St-Louis</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Kubatova%2C+B">B. Kubatova</a>, <a href="/search/astro-ph?searchtype=author&query=Marchant%2C+P">P. Marchant</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+L+P">L. P. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Wofford%2C+A">A. Wofford</a>, <a href="/search/astro-ph?searchtype=author&query=van+Loon%2C+J+T">J. Th. van Loon</a>, <a href="/search/astro-ph?searchtype=author&query=Telford%2C+O+G">O. Grace Telford</a>, <a href="/search/astro-ph?searchtype=author&query=Gotberg%2C+Y">Y. Gotberg</a>, <a href="/search/astro-ph?searchtype=author&query=Bowman%2C+D+M">D. M. Bowman</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Kalari%2C+V+M">V. M. Kalari</a>, <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">M. Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Alkousa%2C+T">T. Alkousa</a> , et al. (56 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="2305.06376v3-abstract-short" style="display: inline;"> Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational-wave events involving spectacular black-hole mergers, indicate that the low-metallicity Universe is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.06376v3-abstract-full').style.display = 'inline'; document.getElementById('2305.06376v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.06376v3-abstract-full" style="display: none;"> Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational-wave events involving spectacular black-hole mergers, indicate that the low-metallicity Universe is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity (Z). The Hubble Space Telescope has devoted 500 orbits to observe 250 massive stars at low Z in the ultraviolet (UV) with the COS and STIS spectrographs under the ULLYSES program. The complementary ``X-Shooting ULLYSES'' (XShootU) project provides enhanced legacy value with high-quality optical and near-infrared spectra obtained with the wide-wavelength coverage X-shooter spectrograph at ESO's Very Large Telescope. We present an overview of the XShootU project, showing that combining ULLYSES UV and XShootU optical spectra is critical for the uniform determination of stellar parameters such as effective temperature, surface gravity, luminosity, and abundances, as well as wind properties such as mass-loss rates in function of Z. As uncertainties in stellar and wind parameters percolate into many adjacent areas of Astrophysics, the data and modelling of the XShootU project is expected to be a game-changer for our physical understanding of massive stars at low Z. To be able to confidently interpret James Webb Space Telescope (JWST) spectra of the first stellar generations, the individual spectra of low Z stars need to be understood, which is exactly where XShootU can deliver. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.06376v3-abstract-full').style.display = 'none'; document.getElementById('2305.06376v3-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> 1 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in A&A - 35 Pages, 12 Figures, 4 Tables, 2 Large Tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 675, A154 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.04869">arXiv:2304.04869</a> <span> [<a href="https://arxiv.org/pdf/2304.04869">pdf</a>, <a href="https://arxiv.org/format/2304.04869">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1088/1538-3873/acd1b5">10.1088/1538-3873/acd1b5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The James Webb Space Telescope Mission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gardner%2C+J+P">Jonathan P. Gardner</a>, <a href="/search/astro-ph?searchtype=author&query=Mather%2C+J+C">John C. Mather</a>, <a href="/search/astro-ph?searchtype=author&query=Abbott%2C+R">Randy Abbott</a>, <a href="/search/astro-ph?searchtype=author&query=Abell%2C+J+S">James S. Abell</a>, <a href="/search/astro-ph?searchtype=author&query=Abernathy%2C+M">Mark Abernathy</a>, <a href="/search/astro-ph?searchtype=author&query=Abney%2C+F+E">Faith E. Abney</a>, <a href="/search/astro-ph?searchtype=author&query=Abraham%2C+J+G">John G. Abraham</a>, <a href="/search/astro-ph?searchtype=author&query=Abraham%2C+R">Roberto Abraham</a>, <a href="/search/astro-ph?searchtype=author&query=Abul-Huda%2C+Y+M">Yasin M. Abul-Huda</a>, <a href="/search/astro-ph?searchtype=author&query=Acton%2C+S">Scott Acton</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C+K">Cynthia K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E">Evan Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adler%2C+D+S">David S. Adler</a>, <a href="/search/astro-ph?searchtype=author&query=Adriaensen%2C+M">Maarten Adriaensen</a>, <a href="/search/astro-ph?searchtype=author&query=Aguilar%2C+J+A">Jonathan Albert Aguilar</a>, <a href="/search/astro-ph?searchtype=author&query=Ahmed%2C+M">Mansoor Ahmed</a>, <a href="/search/astro-ph?searchtype=author&query=Ahmed%2C+N+S">Nasif S. Ahmed</a>, <a href="/search/astro-ph?searchtype=author&query=Ahmed%2C+T">Tanjira Ahmed</a>, <a href="/search/astro-ph?searchtype=author&query=Albat%2C+R">R眉deger Albat</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+L">Lo茂c Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Alberts%2C+S">Stacey Alberts</a>, <a href="/search/astro-ph?searchtype=author&query=Aldridge%2C+D">David Aldridge</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+M+M">Mary Marsha Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+S+S">Shaune S. Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Altenburg%2C+M">Martin Altenburg</a> , et al. (983 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="2304.04869v1-abstract-short" style="display: inline;"> Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astrono… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.04869v1-abstract-full').style.display = 'inline'; document.getElementById('2304.04869v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.04869v1-abstract-full" style="display: none;"> Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.04869v1-abstract-full').style.display = 'none'; document.getElementById('2304.04869v1-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 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 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/2210.17434">arXiv:2210.17434</a> <span> [<a href="https://arxiv.org/pdf/2210.17434">pdf</a>, <a href="https://arxiv.org/format/2210.17434">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1088/1538-3873/acaebd">10.1088/1538-3873/acaebd <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Near Infrared Imager and Slitless Spectrograph for the James Webb Space Telescope -- IV. Aperture Masking Interferometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sivaramakrishnan%2C+A">Anand Sivaramakrishnan</a>, <a href="/search/astro-ph?searchtype=author&query=Tuthill%2C+P">Peter Tuthill</a>, <a href="/search/astro-ph?searchtype=author&query=Lloyd%2C+J+P">James P. Lloyd</a>, <a href="/search/astro-ph?searchtype=author&query=Greenbaum%2C+A+Z">Alexandra Z. Greenbaum</a>, <a href="/search/astro-ph?searchtype=author&query=Thatte%2C+D">Deepashri Thatte</a>, <a href="/search/astro-ph?searchtype=author&query=Cooper%2C+R+A">Rachel A. Cooper</a>, <a href="/search/astro-ph?searchtype=author&query=Vandal%2C+T">Thomas Vandal</a>, <a href="/search/astro-ph?searchtype=author&query=Kammerer%2C+J">Jens Kammerer</a>, <a href="/search/astro-ph?searchtype=author&query=Sanchez-Bermudez%2C+J">Joel Sanchez-Bermudez</a>, <a href="/search/astro-ph?searchtype=author&query=Pope%2C+B+J+S">Benjamin J. S. Pope</a>, <a href="/search/astro-ph?searchtype=author&query=Blakely%2C+D">Dori Blakely</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+L">Lo茂c Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Cook%2C+N+J">Neil J. Cook</a>, <a href="/search/astro-ph?searchtype=author&query=Johnstone%2C+D">Doug Johnstone</a>, <a href="/search/astro-ph?searchtype=author&query=Martel%2C+A+R">Andr茅 R. Martel</a>, <a href="/search/astro-ph?searchtype=author&query=Volk%2C+K">Kevin Volk</a>, <a href="/search/astro-ph?searchtype=author&query=Soulain%2C+A">Anthony Soulain</a>, <a href="/search/astro-ph?searchtype=author&query=Artigau%2C+%C3%89">脡tienne Artigau</a>, <a href="/search/astro-ph?searchtype=author&query=Lafreni%C3%A8re%2C+D">David Lafreni猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Willott%2C+C+J">Chris J. Willott</a>, <a href="/search/astro-ph?searchtype=author&query=Parmentier%2C+S">S茅bastien Parmentier</a>, <a href="/search/astro-ph?searchtype=author&query=Ford%2C+K+E+S">K. E. Saavik Ford</a>, <a href="/search/astro-ph?searchtype=author&query=McKernan%2C+B">Barry McKernan</a>, <a href="/search/astro-ph?searchtype=author&query=Vila%2C+M+B">M. Bego帽a Vila</a>, <a href="/search/astro-ph?searchtype=author&query=Rowlands%2C+N">Neil Rowlands</a> , et al. (14 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="2210.17434v2-abstract-short" style="display: inline;"> The James Webb Space Telescope's Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) flies a 7-hole non-redundant mask (NRM), the first such interferometer in space, operating at 3-5 \micron~wavelengths, and a bright limit of $\simeq 4$ magnitudes in W2. We describe the NIRISS Aperture Masking Interferometry (AMI) mode to help potential observers understand its underlying principles, pres… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.17434v2-abstract-full').style.display = 'inline'; document.getElementById('2210.17434v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.17434v2-abstract-full" style="display: none;"> The James Webb Space Telescope's Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) flies a 7-hole non-redundant mask (NRM), the first such interferometer in space, operating at 3-5 \micron~wavelengths, and a bright limit of $\simeq 4$ magnitudes in W2. We describe the NIRISS Aperture Masking Interferometry (AMI) mode to help potential observers understand its underlying principles, present some sample science cases, explain its operational observing strategies, indicate how AMI proposals can be developed with data simulations, and how AMI data can be analyzed. We also present key results from commissioning AMI. Since the allied Kernel Phase Imaging (KPI) technique benefits from AMI operational strategies, we also cover NIRISS KPI methods and analysis techniques, including a new user-friendly KPI pipeline. The NIRISS KPI bright limit is $\simeq 8$ W2 magnitudes. AMI (and KPI) achieve an inner working angle of $\sim 70$ mas that is well inside the $\sim 400$ mas NIRCam inner working angle for its circular occulter coronagraphs at comparable wavelengths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.17434v2-abstract-full').style.display = 'none'; document.getElementById('2210.17434v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 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">30 pages, 10 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/2207.05632">arXiv:2207.05632</a> <span> [<a href="https://arxiv.org/pdf/2207.05632">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1088/1538-3873/acb293">10.1088/1538-3873/acb293 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Science Performance of JWST as Characterized in Commissioning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rigby%2C+J">Jane Rigby</a>, <a href="/search/astro-ph?searchtype=author&query=Perrin%2C+M">Marshall Perrin</a>, <a href="/search/astro-ph?searchtype=author&query=McElwain%2C+M">Michael McElwain</a>, <a href="/search/astro-ph?searchtype=author&query=Kimble%2C+R">Randy Kimble</a>, <a href="/search/astro-ph?searchtype=author&query=Friedman%2C+S">Scott Friedman</a>, <a href="/search/astro-ph?searchtype=author&query=Lallo%2C+M">Matt Lallo</a>, <a href="/search/astro-ph?searchtype=author&query=Doyon%2C+R">Ren茅 Doyon</a>, <a href="/search/astro-ph?searchtype=author&query=Feinberg%2C+L">Lee Feinberg</a>, <a href="/search/astro-ph?searchtype=author&query=Ferruit%2C+P">Pierre Ferruit</a>, <a href="/search/astro-ph?searchtype=author&query=Glasse%2C+A">Alistair Glasse</a>, <a href="/search/astro-ph?searchtype=author&query=Rieke%2C+M">Marcia Rieke</a>, <a href="/search/astro-ph?searchtype=author&query=Rieke%2C+G">George Rieke</a>, <a href="/search/astro-ph?searchtype=author&query=Wright%2C+G">Gillian Wright</a>, <a href="/search/astro-ph?searchtype=author&query=Willott%2C+C">Chris Willott</a>, <a href="/search/astro-ph?searchtype=author&query=Colon%2C+K">Knicole Colon</a>, <a href="/search/astro-ph?searchtype=author&query=Milam%2C+S">Stefanie Milam</a>, <a href="/search/astro-ph?searchtype=author&query=Neff%2C+S">Susan Neff</a>, <a href="/search/astro-ph?searchtype=author&query=Stark%2C+C">Christopher Stark</a>, <a href="/search/astro-ph?searchtype=author&query=Valenti%2C+J">Jeff Valenti</a>, <a href="/search/astro-ph?searchtype=author&query=Abell%2C+J">Jim Abell</a>, <a href="/search/astro-ph?searchtype=author&query=Abney%2C+F">Faith Abney</a>, <a href="/search/astro-ph?searchtype=author&query=Abul-Huda%2C+Y">Yasin Abul-Huda</a>, <a href="/search/astro-ph?searchtype=author&query=Acton%2C+D+S">D. Scott Acton</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E">Evan Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adler%2C+D">David Adler</a> , et al. (601 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="2207.05632v5-abstract-short" style="display: inline;"> This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05632v5-abstract-full').style.display = 'inline'; document.getElementById('2207.05632v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.05632v5-abstract-full" style="display: none;"> This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05632v5-abstract-full').style.display = 'none'; document.getElementById('2207.05632v5-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 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb293</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PASP 135 048001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.13676">arXiv:2106.13676</a> <span> [<a href="https://arxiv.org/pdf/2106.13676">pdf</a>, <a href="https://arxiv.org/format/2106.13676">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stab1853">10.1093/mnras/stab1853 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultraviolet Line Profiles of Slowly Rotating Massive Star Winds Using the "Analytic Dynamical Magnetosphere" Formalism </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Hennicker%2C+L">L. Hennicker</a>, <a href="/search/astro-ph?searchtype=author&query=Fletcher%2C+C">C. Fletcher</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Y. Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">J. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</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="2106.13676v1-abstract-short" style="display: inline;"> Recent large-scale spectropolarimetric surveys have established that a small but significant percentage of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense, radiatively driven stellar wind into circumstellar magnetospheres, whose density and velocity structure can be probed using ultraviolet (UV) spectroscopy of wind-sensi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13676v1-abstract-full').style.display = 'inline'; document.getElementById('2106.13676v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.13676v1-abstract-full" style="display: none;"> Recent large-scale spectropolarimetric surveys have established that a small but significant percentage of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense, radiatively driven stellar wind into circumstellar magnetospheres, whose density and velocity structure can be probed using ultraviolet (UV) spectroscopy of wind-sensitive resonance lines. Coupled with appropriate magnetosphere models, UV spectroscopy provides a valuable way to investigate the wind-field interaction, and can yield quantitative estimates of the wind parameters of magnetic massive stars. We report a systematic investigation of the formation of UV resonance lines in slowly rotating magnetic massive stars with dynamical magnetospheres. We pair the Analytic Dynamical Magnetosphere (ADM) formalism with a simplified radiative transfer technique to produce synthetic UV line profiles. Using a grid of models, we examine the effect of magnetosphere size, the line strength parameter, and the cooling parameter on the structure and modulation of the line profile. We find that magnetic massive stars uniquely exhibit redshifted absorption at most viewing angles and magnetosphere sizes, and that significant changes to the shape and variation of the line profile with varying line strengths can be explained by examining the individual wind components described in the ADM formalism. Finally, we show that the cooling parameter has a negligible effect on the line profiles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13676v1-abstract-full').style.display = 'none'; document.getElementById('2106.13676v1-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 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 15 figures, accepted to 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/2105.08192">arXiv:2105.08192</a> <span> [<a href="https://arxiv.org/pdf/2105.08192">pdf</a>, <a href="https://arxiv.org/format/2105.08192">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stab1454">10.1093/mnras/stab1454 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Confirmation of xi^1 CMa's ultra-slow rotation: magnetic polarity reversal and a dramatic change in magnetospheric UV emission lines </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Henrichs%2C+H+F">H. F. Henrichs</a>, <a href="/search/astro-ph?searchtype=author&query=Kochukhov%2C+O">O. Kochukhov</a>, <a href="/search/astro-ph?searchtype=author&query=Rivinius%2C+T">T. Rivinius</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</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="2105.08192v1-abstract-short" style="display: inline;"> The magnetic beta Cep pulsator xi^1 CMa has the longest rotational period of any known magnetic B-type star. It is also the only magnetic B-type star with magnetospheric emission that is known to be modulated by both rotation and pulsation. We report here the first unambiguous detection of a negative longitudinal magnetic field in xi^1 CMa (<Bz>=-87 +/- 2 G in 2019 and <Bz>=-207 +/- 3 G in 2020),… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.08192v1-abstract-full').style.display = 'inline'; document.getElementById('2105.08192v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.08192v1-abstract-full" style="display: none;"> The magnetic beta Cep pulsator xi^1 CMa has the longest rotational period of any known magnetic B-type star. It is also the only magnetic B-type star with magnetospheric emission that is known to be modulated by both rotation and pulsation. We report here the first unambiguous detection of a negative longitudinal magnetic field in xi^1 CMa (<Bz>=-87 +/- 2 G in 2019 and <Bz>=-207 +/- 3 G in 2020), as well as the results of ongoing monitoring of the star's Halpha variability. We examine evidence for deviation from a purely dipolar topology. We also report a new HST UV spectrum of xi^1 CMa obtained near magnetic null that is consistent with an equatorial view of the magnetosphere, as evidenced by its similarity to the UV spectrum of beta Cep obtained near maximum emission. The new UV spectrum of xi^1 CMa provides additional evidence for the extremely long rotation period of this star via comparison to archival data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.08192v1-abstract-full').style.display = 'none'; document.getElementById('2105.08192v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, Accepted 2021 May 14 to Monthly Notices of the Royal Astronomical Society 2021</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.07482">arXiv:2010.07482</a> <span> [<a href="https://arxiv.org/pdf/2010.07482">pdf</a>, <a href="https://arxiv.org/format/2010.07482">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/staa3768">10.1093/mnras/staa3768 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> New observations of NGC 1624-2 reveal a complex magnetospheric structure and underlying surface magnetic geometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Z. Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Seadrow%2C+S">S. Seadrow</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.07482v3-abstract-short" style="display: inline;"> NGC 1624-2 is the most strongly magnetized O-type star known. Previous spectroscopic observations of this object in the ultraviolet provided evidence that it hosts a large and dense circumstellar magnetosphere. Follow-up observations obtained with the \textit{Hubble Space Telescope} not only confirm that previous inference, but also suggest that NGC 1624-2's magnetosphere has a complex structure.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07482v3-abstract-full').style.display = 'inline'; document.getElementById('2010.07482v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.07482v3-abstract-full" style="display: none;"> NGC 1624-2 is the most strongly magnetized O-type star known. Previous spectroscopic observations of this object in the ultraviolet provided evidence that it hosts a large and dense circumstellar magnetosphere. Follow-up observations obtained with the \textit{Hubble Space Telescope} not only confirm that previous inference, but also suggest that NGC 1624-2's magnetosphere has a complex structure. Furthermore, an expanded spectropolarimetric time series shows a potential departure from a dipolar magnetic field geometry, which could mean that the strongest field detected at the surface of an O-type star is also topologically complex. This result raises important questions regarding the origin and evolution of magnetic fields in massive stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07482v3-abstract-full').style.display = 'none'; document.getElementById('2010.07482v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 3 figures, accepted for publication by MNRAS (2020 December 1)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 501, 2677 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.08748">arXiv:1912.08748</a> <span> [<a href="https://arxiv.org/pdf/1912.08748">pdf</a>, <a href="https://arxiv.org/format/1912.08748">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Quantitative Modeling of the UV Line Profiles of Magnetic Massive Stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">Christiana Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">Veronique Petit</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">Alexandre David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</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="1912.08748v1-abstract-short" style="display: inline;"> Recent spectropolarimetric surveys (MiMeS, BOB) have revealed that approximately 7% of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense radiatively driven stellar wind into a circumstellar magnetosphere. Wind-sensitive UV spectral lines can probe the density and velocity structure of massive star magnetospheres, providing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08748v1-abstract-full').style.display = 'inline'; document.getElementById('1912.08748v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.08748v1-abstract-full" style="display: none;"> Recent spectropolarimetric surveys (MiMeS, BOB) have revealed that approximately 7% of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense radiatively driven stellar wind into a circumstellar magnetosphere. Wind-sensitive UV spectral lines can probe the density and velocity structure of massive star magnetospheres, providing insight into wind-field interactions. To date, large-scale magnetohydrodynamic modeling of this phenomenon has been limited by the associated computational cost. Our analysis, using the Analytic Dynamical Magnetosphere model, solves this problem by applying a simple analytic prescription to efficiently calculate synthetic UV spectral lines. It can therefore be applied in the context of a larger parameter study to derive the wind properties for the population of known magnetic O stars. We also present the latest UV spectra of the magnetic O star NGC 1624-2 obtained with HST/COS, which test the limits of our models and suggest a particularly complex magnetospheric structure for this archetypal object. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.08748v1-abstract-full').style.display = 'none'; document.getElementById('1912.08748v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">Stellar Magnetic Fields: A workshop in honor of the career and contributions of John Landstreet</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.04687">arXiv:1908.04687</a> <span> [<a href="https://arxiv.org/pdf/1908.04687">pdf</a>, <a href="https://arxiv.org/format/1908.04687">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Massive stars in extremely metal-poor galaxies: A window into the past </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+C">J. C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cervi%C3%B1o%2C+M">M. Cervi帽o</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gieles%2C+M">M. Gieles</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=van+Loon%2C+J+T">J. Th. van Loon</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">S. E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Negueruela%2C+I">I. Negueruela</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Sim%C3%B3n-D%C3%ADaz%2C+S">S. Sim贸n-D铆az</a>, <a href="/search/astro-ph?searchtype=author&query=Sz%C3%A9csi%2C+D">D. Sz茅csi</a>, <a href="/search/astro-ph?searchtype=author&query=Tramper%2C+F">F. Tramper</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J">J. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Wofford%2C+A">A. Wofford</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="1908.04687v1-abstract-short" style="display: inline;"> Cosmic History has witnessed the lives and deaths of multiple generations of massive stars, all of them invigorating their host galaxies with ionizing photons, kinetic energy, fresh material and stellar-mass black holes. Ubiquitous engines as they are, Astrophysics needs a good understanding of their formation, evolution, properties and yields throughout the history of the Universe, and with decre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.04687v1-abstract-full').style.display = 'inline'; document.getElementById('1908.04687v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.04687v1-abstract-full" style="display: none;"> Cosmic History has witnessed the lives and deaths of multiple generations of massive stars, all of them invigorating their host galaxies with ionizing photons, kinetic energy, fresh material and stellar-mass black holes. Ubiquitous engines as they are, Astrophysics needs a good understanding of their formation, evolution, properties and yields throughout the history of the Universe, and with decreasing metal content mimicking the environment at the earliest epochs. Ultimately, a physical model that could be extrapolated to zero metallicity would enable tackling long-standing questions such as "What did the First, very massive stars of the Universe look like?" or "What was their role in the re-ionization of the Universe?". Yet, most our knowledge of metal-poor massive stars is drawn from one single point in metallicity. Massive stars in the Small Magellanic Cloud (SMC, $\sim 1/5 Z_{\odot}$) currently serve as templates for low-metallicity objects in the early Universe, even though significant differences with respect to massive stars with poorer metal content have been reported. This White Paper summarizes the current knowledge on extremely (sub-SMC) metal poor massive stars, highlighting the most outstanding open questions and the need to supersede the SMC as standard. A new paradigm can be built from nearby extremely metal-poor galaxies that make a new metallicity ladder, but massive stars in these galaxies are out of reach to current observational facilities. Such task would require an L-size mission, consisting of a 10m-class space telescope operating in the optical and the ultraviolet ranges. Alternatively, we propose that ESA unites efforts with NASA to make the LUVOIR mission concept a reality, thus continuing the successful partnership that made Hubble Space Telescope one of the greatest observatories of all time. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.04687v1-abstract-full').style.display = 'none'; document.getElementById('1908.04687v1-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 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">A white paper submitted for the Voyage 2050 long-term plan in the ESA Science Programme. 21 pages, 1 table, 6 figures. arXiv admin note: substantial text overlap with arXiv:1903.05235</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.05235">arXiv:1903.05235</a> <span> [<a href="https://arxiv.org/pdf/1903.05235">pdf</a>, <a href="https://arxiv.org/format/1903.05235">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Walking along Cosmic History: Metal-poor Massive Stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Wofford%2C+A">A. Wofford</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+C">J. C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Cervi%C3%B1o%2C+M">M. Cervi帽o</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</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="1903.05235v1-abstract-short" style="display: inline;"> Multiple generations of massive stars have lived and died during Cosmic History, invigorating host galaxies with ionizing photons, kinetic energy, fresh material and stellar-size black holes. At present, massive stars in the Small Magellanic Cloud (SMC) serve as templates for low-metallicity objects in the early Universe. However, recent results have highlighted important differences in the evolut… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.05235v1-abstract-full').style.display = 'inline'; document.getElementById('1903.05235v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.05235v1-abstract-full" style="display: none;"> Multiple generations of massive stars have lived and died during Cosmic History, invigorating host galaxies with ionizing photons, kinetic energy, fresh material and stellar-size black holes. At present, massive stars in the Small Magellanic Cloud (SMC) serve as templates for low-metallicity objects in the early Universe. However, recent results have highlighted important differences in the evolution, death and feedback of massive stars with poorer metal content that better matches the extremely low metallicity of previous Cosmic epochs. This paper proposes to supersede the SMC standard with a new metallicity ladder built from very metal-poor galaxies, and provides a brief overview of the technological facilities needed to this aim. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.05235v1-abstract-full').style.display = 'none'; document.getElementById('1903.05235v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">An abridged version of this paper was submitted to the Astro2020 Decadal Survey on Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.10113">arXiv:1811.10113</a> <span> [<a href="https://arxiv.org/pdf/1811.10113">pdf</a>, <a href="https://arxiv.org/format/1811.10113">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/sty3227">10.1093/mnras/sty3227 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extreme resonance line profile variations in the ultraviolet spectra of NGC 1624-2: probing the giant magnetosphere of the most strongly magnetized known O-type star </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a>, <a href="/search/astro-ph?searchtype=author&query=MacInnis%2C+R">R. MacInnis</a>, <a href="/search/astro-ph?searchtype=author&query=Barb%C3%A1%2C+R+H">R. H. Barb谩</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">D. H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Y. Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">S. P. Owocki</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1811.10113v1-abstract-short" style="display: inline;"> In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the CIV and SiIV doublets between low state… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.10113v1-abstract-full').style.display = 'inline'; document.getElementById('1811.10113v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.10113v1-abstract-full" style="display: none;"> In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the CIV and SiIV doublets between low state and high state are the largest observed in any magnetic O-type star, consistent with the expected properties of NGC 1624-2's magnetosphere. We also observe a redshifted absorption component in the low state, a feature not seen in most stars. We present preliminary modelling efforts based on the Analytic Dynamical Magnetosphere (ADM) formalism, demonstrating the necessity of using non-spherically symmetric models to determine wind/magnetospheric properties of magnetic O stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.10113v1-abstract-full').style.display = 'none'; document.getElementById('1811.10113v1-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 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 6 figures, accepted for publication by MNRAS (23 November 2018)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 483, 2814 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.08123">arXiv:1801.08123</a> <span> [<a href="https://arxiv.org/pdf/1801.08123">pdf</a>, <a href="https://arxiv.org/ps/1801.08123">ps</a>, <a href="https://arxiv.org/format/1801.08123">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Massive star winds interacting with magnetic fields on various scales </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N">N. Walborn</a>, <a href="/search/astro-ph?searchtype=author&query=MacInnis%2C+R">R. MacInnis</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="1801.08123v1-abstract-short" style="display: inline;"> One of the defining processes which govern massive star evolution is their continuous mass loss via dense, supersonic line-driven winds. In the case of those OB stars which also host a surface magnetic field, the interaction between that field and the ionized outflow leads to complex circumstellar structures known as magnetospheres. In this contribution, we review recent developments in the field… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.08123v1-abstract-full').style.display = 'inline'; document.getElementById('1801.08123v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.08123v1-abstract-full" style="display: none;"> One of the defining processes which govern massive star evolution is their continuous mass loss via dense, supersonic line-driven winds. In the case of those OB stars which also host a surface magnetic field, the interaction between that field and the ionized outflow leads to complex circumstellar structures known as magnetospheres. In this contribution, we review recent developments in the field of massive star magnetospheres, including current efforts to characterize the largest magnetosphere surrounding an O star: that of NGC 1624-2. We also discuss the potential of the `analytic dynamical magnetosphere' (ADM) model to interpret multi-wavelength observations. Finally, we examine the possible effects of -- heretofore undetected -- small-scale magnetic fields on massive star winds and compare their hypothetical consequences to existing, unexplained observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.08123v1-abstract-full').style.display = 'none'; document.getElementById('1801.08123v1-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 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 1 figure, Conference proceedings: "Stars with a stable magnetic field: from pre-main sequence to compact remnants", Brno, Czech Republic, 2017</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.02627">arXiv:1706.02627</a> <span> [<a href="https://arxiv.org/pdf/1706.02627">pdf</a>, <a href="https://arxiv.org/format/1706.02627">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stx1443">10.1093/mnras/stx1443 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mass loss rates from mid-IR excesses in LMC and SMC O stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</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="1706.02627v1-abstract-short" style="display: inline;"> We use a combination of BVJHK and Spitzer [3.6], [5.8] and [8.0] photometry to determine IR excesses for a sample of 58 LMC and 46 SMC O stars. This sample is ideal for determining IR excesses because the very small line of sight reddening minimizes uncertainties due to extinction corrections. We use the core-halo model developed by Lamers & Waters (1984a) to translate the excesses into mass loss… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.02627v1-abstract-full').style.display = 'inline'; document.getElementById('1706.02627v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.02627v1-abstract-full" style="display: none;"> We use a combination of BVJHK and Spitzer [3.6], [5.8] and [8.0] photometry to determine IR excesses for a sample of 58 LMC and 46 SMC O stars. This sample is ideal for determining IR excesses because the very small line of sight reddening minimizes uncertainties due to extinction corrections. We use the core-halo model developed by Lamers & Waters (1984a) to translate the excesses into mass loss rates and demonstrate that the results of this simple model agree with the more sophisticated CMFGEN models to within a factor of 2. Taken at face value, the derived mass loss rates are larger than those predicted by Vink et al. (2001), and the magnitude of the disagreement increases with decreasing luminosity. However, the IR excesses need not imply large mass loss rates. Instead, we argue that they probably indicate that the outer atmospheres of O stars contain complex structures and that their winds are launched with much smaller velocity gradients than normally assumed. If this is the case, it could affect the theoretical and observational interpretations of the "weak wind" problem, where classical mass loss indicators suggest that the mass loss rates of lower luminosity O stars are far less than expected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.02627v1-abstract-full').style.display = 'none'; document.getElementById('1706.02627v1-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">15 pages, 10 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/1511.08425">arXiv:1511.08425</a> <span> [<a href="https://arxiv.org/pdf/1511.08425">pdf</a>, <a href="https://arxiv.org/ps/1511.08425">ps</a>, <a href="https://arxiv.org/format/1511.08425">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stv2568">10.1093/mnras/stv2568 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The MiMeS Survey of Magnetism in Massive Stars: Introduction and overview </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">C. Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Alecian%2C+E">E. Alecian</a>, <a href="/search/astro-ph?searchtype=author&query=Grunhut%2C+J+H">J. H. Grunhut</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=de+Batz%2C+B">B. de Batz</a>, <a href="/search/astro-ph?searchtype=author&query=Bohlender%2C+D+A">D. A. Bohlender</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">D. H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Henrichs%2C+H+F">H. F. Henrichs</a>, <a href="/search/astro-ph?searchtype=author&query=Kochukhov%2C+O">O. Kochukhov</a>, <a href="/search/astro-ph?searchtype=author&query=Landstreet%2C+J+D">J. D. Landstreet</a>, <a href="/search/astro-ph?searchtype=author&query=Manset%2C+N">N. Manset</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Mathis%2C+S">S. Mathis</a>, <a href="/search/astro-ph?searchtype=author&query=Oksala%2C+M+E">M. E. Oksala</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">S. P. Owocki</a>, <a href="/search/astro-ph?searchtype=author&query=Rivinius%2C+T">Th. Rivinius</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Townsend%2C+R+H+D">R. H. D. Townsend</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Braithwaite%2C+J">J. Braithwaite</a>, <a href="/search/astro-ph?searchtype=author&query=Briquet%2C+M">M. Briquet</a>, <a href="/search/astro-ph?searchtype=author&query=Carciofi%2C+A+C">A. C. Carciofi</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="1511.08425v1-abstract-short" style="display: inline;"> The MiMeS project is a large-scale, high resolution, sensitive spectropolarimetric investigation of the magnetic properties of O and early B type stars. Initiated in 2008 and completed in 2013, the project was supported by 3 Large Program allocations, as well as various programs initiated by independent PIs and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.08425v1-abstract-full').style.display = 'inline'; document.getElementById('1511.08425v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.08425v1-abstract-full" style="display: none;"> The MiMeS project is a large-scale, high resolution, sensitive spectropolarimetric investigation of the magnetic properties of O and early B type stars. Initiated in 2008 and completed in 2013, the project was supported by 3 Large Program allocations, as well as various programs initiated by independent PIs and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS at the Canada-France-Hawaii Telescope, Narval at the T茅lescope Bernard Lyot, and HARPSpol at the European Southern Observatory La Silla 3.6m telescope, making MiMeS by far the largest systematic investigation of massive star magnetism ever undertaken. In this paper, the first in a series reporting the general results of the survey, we introduce the scientific motivation and goals, describe the sample of targets, review the instrumentation and observational techniques used, explain the exposure time calculation designed to provide sensitivity to surface dipole fields above approximately 100 G, discuss the polarimetric performance, stability and uncertainty of the instrumentation, and summarize the previous and forthcoming publications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.08425v1-abstract-full').style.display = 'none'; document.getElementById('1511.08425v1-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 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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 MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 456, 2-22 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.08621">arXiv:1507.08621</a> <span> [<a href="https://arxiv.org/pdf/1507.08621">pdf</a>, <a href="https://arxiv.org/format/1507.08621">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</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/stv1741">10.1093/mnras/stv1741 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-ray emission from the giant magnetosphere of the magnetic O-type star NGC 1624-2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">D. H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Y. Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">S. P. Owocki</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Leutenegger%2C+M">M. Leutenegger</a>, <a href="/search/astro-ph?searchtype=author&query=Gagn%C3%A9%2C+M">M. Gagn茅</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="1507.08621v1-abstract-short" style="display: inline;"> We observed NGC 1624-2, the O-type star with the largest known magnetic field Bp~20 kG), in X-rays with the ACIS-S camera onboard the Chandra X-ray Observatory. Our two observations were obtained at the minimum and maximum of the periodic Halpha emission cycle, corresponding to the rotational phases where the magnetic field is the closest to equator-on and pole-on, respectively. With these observa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.08621v1-abstract-full').style.display = 'inline'; document.getElementById('1507.08621v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.08621v1-abstract-full" style="display: none;"> We observed NGC 1624-2, the O-type star with the largest known magnetic field Bp~20 kG), in X-rays with the ACIS-S camera onboard the Chandra X-ray Observatory. Our two observations were obtained at the minimum and maximum of the periodic Halpha emission cycle, corresponding to the rotational phases where the magnetic field is the closest to equator-on and pole-on, respectively. With these observations, we aim to characterise the star's magnetosphere via the X-ray emission produced by magnetically confined wind shocks. Our main findings are: (i) The observed spectrum of NGC 1624-2 is hard, similar to the magnetic O-type star Theta 1 Ori C, with only a few photons detected below 0.8 keV. The emergent X-ray flux is 30% lower at the Halpha minimum phase. (ii) Our modelling indicated that this seemingly hard spectrum is in fact a consequence of relatively soft intrinsic emission, similar to other magnetic Of?p stars, combined with a large amount of local absorption (~1-3 x 10^22 cm^-2). This combination is necessary to reproduce both the prominent Mg and Si spectral features, and the lack of flux at low energies. NGC 1624-2 is intrinsically luminous in X-rays (log LX emission ~ 33.4) but 70-95% of the X-ray emission produced by magnetically confined wind shocks is absorbed before it escapes the magnetosphere (log LX ISM corrected ~ 32.5). (iii) The high X-ray luminosity, its variation with stellar rotation, and its large attenuation are all consistent with a large dynamical magnetosphere with magnetically confined wind shocks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.08621v1-abstract-full').style.display = 'none'; document.getElementById('1507.08621v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 July, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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 in MNRAS 13 pages, 10 figures, 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 453, 3288-3299 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.09196">arXiv:1506.09196</a> <span> [<a href="https://arxiv.org/pdf/1506.09196">pdf</a>, <a href="https://arxiv.org/ps/1506.09196">ps</a>, <a href="https://arxiv.org/format/1506.09196">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stv1435">10.1093/mnras/stv1435 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> FUSE, STIS, and Keck spectroscopic analysis of the UV-bright star vZ 1128 in M3 (NGC 5272) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chayer%2C+P">Pierre Chayer</a>, <a href="/search/astro-ph?searchtype=author&query=Dixon%2C+W+V">William V. Dixon</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Ooghe-Tabanou%2C+B">Benjamin Ooghe-Tabanou</a>, <a href="/search/astro-ph?searchtype=author&query=Reid%2C+I+N">I. Neill Reid</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="1506.09196v1-abstract-short" style="display: inline;"> We present a spectral analysis of the UV-bright star vZ 1128 in M3 based on observations with the Far Ultraviolet Spectroscopic Explorer (FUSE), the Space Telescope Imaging Spectrograph (STIS), and the Keck HIRES echelle spectrograph. By fitting the H I, He I, and He II lines in the Keck spectrum with non-LTE H-He models, we obtain Teff = 36,600 K, log g = 3.95, and log N(He)/N(H) = -0.84. The sta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.09196v1-abstract-full').style.display = 'inline'; document.getElementById('1506.09196v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.09196v1-abstract-full" style="display: none;"> We present a spectral analysis of the UV-bright star vZ 1128 in M3 based on observations with the Far Ultraviolet Spectroscopic Explorer (FUSE), the Space Telescope Imaging Spectrograph (STIS), and the Keck HIRES echelle spectrograph. By fitting the H I, He I, and He II lines in the Keck spectrum with non-LTE H-He models, we obtain Teff = 36,600 K, log g = 3.95, and log N(He)/N(H) = -0.84. The star's FUSE and STIS spectra show photospheric absorption from C, N, O, Al, Si, P, S, Fe, and Ni. No stellar features from elements beyond the iron peak are observed. Both components of the N V 1240 doublet exhibit P~Cygni profiles, indicating a weak stellar wind, but no other wind features are seen. The star's photospheric abundances appear to have changed little since it left the red giant branch (RGB). Its C, N, O, Al, Si, Fe, and Ni abundances are consistent with published values for the red-giant stars in M3, and the relative abundances of C, N, and O follow the trends seen on the cluster RGB. In particular, its low C abundance suggests that the star left the asymptotic giant branch before the onset of third dredge-up. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.09196v1-abstract-full').style.display = 'none'; document.getElementById('1506.09196v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">15 pages, 10 figures, to be published 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/1506.08572">arXiv:1506.08572</a> <span> [<a href="https://arxiv.org/pdf/1506.08572">pdf</a>, <a href="https://arxiv.org/ps/1506.08572">ps</a>, <a href="https://arxiv.org/format/1506.08572">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</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/stv1445">10.1093/mnras/stv1445 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The changing UV and X-ray properties of the Of?p star CPD -28 2561 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Naze%2C+Y">Yael Naze</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alex W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">Asif ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">Gregg A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Rauw%2C+G">Gregor Rauw</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">Nolan R. Walborn</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="1506.08572v2-abstract-short" style="display: inline;"> The Of?p star CPD -28 2561 was monitored at high energies with XMM-Newton and HST. In X-rays, this magnetic oblique rotator displays bright and hard emission that varies by ~55% with rotational phase. These changes occur in phase with optical variations, as expected for magnetically confined winds; there are two maxima and two minima in X-rays during the 73d rotational period of CPD -28 2561. Howe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.08572v2-abstract-full').style.display = 'inline'; document.getElementById('1506.08572v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.08572v2-abstract-full" style="display: none;"> The Of?p star CPD -28 2561 was monitored at high energies with XMM-Newton and HST. In X-rays, this magnetic oblique rotator displays bright and hard emission that varies by ~55% with rotational phase. These changes occur in phase with optical variations, as expected for magnetically confined winds; there are two maxima and two minima in X-rays during the 73d rotational period of CPD -28 2561. However, contrary to previously studied cases, no significant hardness variation is detected between minima and maxima, with the exception of the second minimum which is slightly distinct from the first one. In the UV domain, broad-band fluxes remain stable while line profiles display large variations. Stronger absorptions at low velocities are observed when the magnetic equator is seen edge-on, which can be reproduced by a detailed 3D model. However, a difference in absorption at high velocities in the CIV and NV lines is also detected for the two phases where the confined wind is seen nearly pole-on. This suggests the presence of strong asymmetries about the magnetic equator, mostly in the free-flowing wind (rather than in the confined dynamical magnetosphere). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.08572v2-abstract-full').style.display = 'none'; document.getElementById('1506.08572v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">14 pages, 11 figures, accepted for publication by MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 452, 2641-2653 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.2868">arXiv:1407.2868</a> <span> [<a href="https://arxiv.org/pdf/1407.2868">pdf</a>, <a href="https://arxiv.org/ps/1407.2868">ps</a>, <a href="https://arxiv.org/format/1407.2868">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/s10509-014-2050-4">10.1007/s10509-014-2050-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> UVMag: stellar formation, evolution, structure and environment with space UV and visible spectropolarimetry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">C. Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Baade%2C+D">D. Baade</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gry%2C+C">C. Gry</a>, <a href="/search/astro-ph?searchtype=author&query=Hussain%2C+G">G. Hussain</a>, <a href="/search/astro-ph?searchtype=author&query=Lebre%2C+A">A. Lebre</a>, <a href="/search/astro-ph?searchtype=author&query=Morin%2C+J">J. Morin</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+P">P. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Vidotto%2C+A+A">A. A. Vidotto</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=consortium%2C+t+U">the UVMag consortium</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="1407.2868v1-abstract-short" style="display: inline;"> Important insights into the formation, structure, evolution and environment of all types of stars can be obtained through the measurement of their winds and possible magnetospheres. However, this has hardly been done up to now mainly because of the lack of UV instrumentation available for long periods of time. To reach this aim, we have designed UVMag, an M-size space mission equipped with a high-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.2868v1-abstract-full').style.display = 'inline'; document.getElementById('1407.2868v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.2868v1-abstract-full" style="display: none;"> Important insights into the formation, structure, evolution and environment of all types of stars can be obtained through the measurement of their winds and possible magnetospheres. However, this has hardly been done up to now mainly because of the lack of UV instrumentation available for long periods of time. To reach this aim, we have designed UVMag, an M-size space mission equipped with a high-resolution spectropolarimeter working in the UV and visible spectral range. The UV domain is crucial in stellar physics as it is very rich in atomic and molecular lines and contains most of the flux of hot stars. Moreover, covering the UV and visible spectral domains at the same time will allow us to study the star and its environment simultaneously. Adding polarimetric power to the spectrograph will multiply tenfold the capabilities of extracting information on stellar magnetospheres, winds, disks, and magnetic fields. Examples of science objectives that can be reached with UVMag are presented for pre-main sequence, main sequence and evolved stars. They will cast new light onto stellar physics by addressing many exciting and important questions. UVMag is currently undergoing a Research and Technology study and will be proposed at the forthcoming ESA call for M-size missions. This spectropolarimeter could also be installed on a large UV and visible observatory (e.g. NASA's LUVOIR project) within a suite of instruments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.2868v1-abstract-full').style.display = 'none'; document.getElementById('1407.2868v1-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, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Accepted in ApSS's special volume on UV astronomy</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.6882">arXiv:1406.6882</a> <span> [<a href="https://arxiv.org/pdf/1406.6882">pdf</a>, <a href="https://arxiv.org/ps/1406.6882">ps</a>, <a href="https://arxiv.org/format/1406.6882">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1117/12.2055191">10.1117/12.2055191 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> NIRISS aperture masking interferometry: an overview of science opportunities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Artigau%2C+%C3%89">脡tienne Artigau</a>, <a href="/search/astro-ph?searchtype=author&query=Sivaramakrishnan%2C+A">Anand Sivaramakrishnan</a>, <a href="/search/astro-ph?searchtype=author&query=Greenbaum%2C+A+Z">Alexandra Z. Greenbaum</a>, <a href="/search/astro-ph?searchtype=author&query=Doyon%2C+R">Ren茅 Doyon</a>, <a href="/search/astro-ph?searchtype=author&query=Goudfrooij%2C+P">Paul Goudfrooij</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alex W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Lafreni%C3%A8re%2C+D">David Lafreni猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Volk%2C+K">Kevin Volk</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+L">Lo茂c Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Martel%2C+A">Andr茅 Martel</a>, <a href="/search/astro-ph?searchtype=author&query=Ford%2C+K+E+S">K. E. Saavik Ford</a>, <a href="/search/astro-ph?searchtype=author&query=McKernan%2C+B+L">Barry L. McKernan</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="1406.6882v1-abstract-short" style="display: inline;"> JWST's Near-Infrared Imager and Slitless Spectrograph (NIRISS) includes an Aperture Masking Interferometry (AMI) mode designed to be used between 2.7渭m and 4.8渭m. At these wavelengths, it will have the highest angular resolution of any mode on JWST, and, for faint targets, of any existing or planned infrastructure. NIRISS AMI is uniquely suited to detect thermal emission of young massive planets a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.6882v1-abstract-full').style.display = 'inline'; document.getElementById('1406.6882v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.6882v1-abstract-full" style="display: none;"> JWST's Near-Infrared Imager and Slitless Spectrograph (NIRISS) includes an Aperture Masking Interferometry (AMI) mode designed to be used between 2.7渭m and 4.8渭m. At these wavelengths, it will have the highest angular resolution of any mode on JWST, and, for faint targets, of any existing or planned infrastructure. NIRISS AMI is uniquely suited to detect thermal emission of young massive planets and will permit the characterization of the mid-IR flux of exoplanets discovered by the GPI and SPHERE adaptive optics surveys. It will also directly detect massive planets found by GAIA through astrometric accelerations, providing the first opportunity ever to get both a mass and a flux measurement for non-transiting giant planets. NIRISS AMI will also enable the study of the nuclear environment of AGNs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.6882v1-abstract-full').style.display = 'none'; document.getElementById('1406.6882v1-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 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Presented at SPIE Astronomical Telescopes + Instrumentation 2014</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1403.5601">arXiv:1403.5601</a> <span> [<a href="https://arxiv.org/pdf/1403.5601">pdf</a>, <a href="https://arxiv.org/ps/1403.5601">ps</a>, <a href="https://arxiv.org/format/1403.5601">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stu565">10.1093/mnras/stu565 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CIR Modulation of the X-ray Flux from the O7.5 III(n)((f)) Star xi Persei? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L">L. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Bohlender%2C+D+A">D. A. Bohlender</a>, <a href="/search/astro-ph?searchtype=author&query=Morrison%2C+N+D">N. D. Morrison</a>, <a href="/search/astro-ph?searchtype=author&query=Blake%2C+M">M. Blake</a>, <a href="/search/astro-ph?searchtype=author&query=Pych%2C+W">W. Pych</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="1403.5601v1-abstract-short" style="display: inline;"> We analyze a 162 ks HETG Chandra observation of the O7.5 III(n)((f)) star xi Per, together with contemporaneous H alpha observations. The X-ray spectrum of this star is similar to other single O stars, and not pathological in any way. Its UV wind lines are known to display cyclical time variability, with a period of 2.086 days, which is thought to be associated with co-rotating interaction regions… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.5601v1-abstract-full').style.display = 'inline'; document.getElementById('1403.5601v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1403.5601v1-abstract-full" style="display: none;"> We analyze a 162 ks HETG Chandra observation of the O7.5 III(n)((f)) star xi Per, together with contemporaneous H alpha observations. The X-ray spectrum of this star is similar to other single O stars, and not pathological in any way. Its UV wind lines are known to display cyclical time variability, with a period of 2.086 days, which is thought to be associated with co-rotating interaction regions (CIRs). We examine the Chandra and H alpha data for variability on this time scale. We find that the X-rays vary by about 15% over the course of the observations and that this variability is out of phase with variable absorption on the blue wing of the H alpha profiles (assumed to be a surrogate for the UV absorption associated with CIRs). While not conclusive, both sets of data are consistent with models where the CIRs are either a source of X-rays or modulate them. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1403.5601v1-abstract-full').style.display = 'none'; document.getElementById('1403.5601v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 March, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">Accepted by MNRAS. 9 pages, 9 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/1401.7995">arXiv:1401.7995</a> <span> [<a href="https://arxiv.org/pdf/1401.7995">pdf</a>, <a href="https://arxiv.org/ps/1401.7995">ps</a>, <a href="https://arxiv.org/format/1401.7995">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/stu008">10.1093/mnras/stu008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measuring mass-loss rates and constraining shock physics using X-ray line profiles of O stars from the Chandra archive </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">David H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Wollman%2C+E+E">Emma E. Wollman</a>, <a href="/search/astro-ph?searchtype=author&query=Leutenegger%2C+M+A">Maurice A. Leutenegger</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alex W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Zsargo%2C+J">Janos Zsargo</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">Stanley P. Owocki</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="1401.7995v1-abstract-short" style="display: inline;"> We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically symmetric wind with embedded shocks, we confirm previous claims that some objects show little or no wind absorption. However, many other objects do show asymme… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.7995v1-abstract-full').style.display = 'inline'; document.getElementById('1401.7995v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1401.7995v1-abstract-full" style="display: none;"> We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically symmetric wind with embedded shocks, we confirm previous claims that some objects show little or no wind absorption. However, many other objects do show asymmetric and blue shifted line profiles, indicative of wind absorption. For these stars, we are able to derive wind mass-loss rates from the ensemble of line profiles, and find values lower by an average factor of 3 than those predicted by current theoretical models, and consistent with H-alpha if clumping factors of f_cl ~ 20 are assumed. The same profile fitting indicates an onset radius of X-rays typically at r ~ 1.5 R_star, and terminal velocities for the X-ray emitting wind component that are consistent with that of the bulk wind. We explore the likelihood that the stars in the sample that do not show significant wind absorption signatures in their line profiles have at least some X-ray emission that arises from colliding wind shocks with a close binary companion. The one clear exception is zeta Oph, a weak-wind star that appears to simply have a very low mass-loss rate. We also reanalyse the results from the canonical O supergiant zeta Pup, using a solar-metallicity wind opacity model and find Mdot = 1.8 \times 10^{-6} M_sun/yr, consistent with recent multi-wavelength determinations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.7995v1-abstract-full').style.display = 'none'; document.getElementById('1401.7995v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 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">18 pages; 8 figures; 4 tables; Monthly Notices of the Royal Astronomical Society, 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/1302.4708">arXiv:1302.4708</a> <span> [<a href="https://arxiv.org/pdf/1302.4708">pdf</a>, <a href="https://arxiv.org/ps/1302.4708">ps</a>, <a href="https://arxiv.org/format/1302.4708">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/stt323">10.1093/mnras/stt323 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase-resolved ultraviolet spectroscopy of the magnetic Of?p star HD 191612 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marcolino%2C+W+L+F">W. L. F. Marcolino</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</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="1302.4708v1-abstract-short" style="display: inline;"> We present for the first time phase-resolved UV spectroscopy of an Of?p star, namely, HD 191612. The observations were acquired with the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope (HST). We report the variability observed in the main photospheric and wind features and compare the results with previous findings for the Of?p star HD 108. We show that UV line stre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.4708v1-abstract-full').style.display = 'inline'; document.getElementById('1302.4708v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1302.4708v1-abstract-full" style="display: none;"> We present for the first time phase-resolved UV spectroscopy of an Of?p star, namely, HD 191612. The observations were acquired with the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope (HST). We report the variability observed in the main photospheric and wind features and compare the results with previous findings for the Of?p star HD 108. We show that UV line strengths, H(alpha), and longitudinal magnetic field, vary coherently according to the rotational period (P = 537.6d), providing additional support for the magnetic oblique rotator scenario. The stellar and wind parameters of HD 191612 are obtained based on NLTE expanding atmosphere models. The peculiar wind line profile variations revealed by the new STIS data - not reproduced by 1D atmosphere models - are addressed through non-spherical MHD simulations coupled with radiative transfer. The basic aspects of the UV variability observed are explained and the structure of the dynamical magnetosphere of HD 191612 is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.4708v1-abstract-full').style.display = 'none'; document.getElementById('1302.4708v1-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 February, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS (9 pages, 6 figures, 3 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/1209.3272">arXiv:1209.3272</a> <span> [<a href="https://arxiv.org/pdf/1209.3272">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Unique Astrophysics in the Lyman Ultraviolet </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Tumlinson%2C+J">Jason Tumlinson</a>, <a href="/search/astro-ph?searchtype=author&query=Aloisi%2C+A">Alessandra Aloisi</a>, <a href="/search/astro-ph?searchtype=author&query=Kriss%2C+G">Gerard Kriss</a>, <a href="/search/astro-ph?searchtype=author&query=France%2C+K">Kevin France</a>, <a href="/search/astro-ph?searchtype=author&query=McCandliss%2C+S">Stephan McCandliss</a>, <a href="/search/astro-ph?searchtype=author&query=Sembach%2C+K">Ken Sembach</a>, <a href="/search/astro-ph?searchtype=author&query=Fox%2C+A">Andrew Fox</a>, <a href="/search/astro-ph?searchtype=author&query=Tripp%2C+T">Todd Tripp</a>, <a href="/search/astro-ph?searchtype=author&query=Jenkins%2C+E">Edward Jenkins</a>, <a href="/search/astro-ph?searchtype=author&query=Beasley%2C+M">Matthew Beasley</a>, <a href="/search/astro-ph?searchtype=author&query=Danforth%2C+C">Charles Danforth</a>, <a href="/search/astro-ph?searchtype=author&query=Shull%2C+M">Michael Shull</a>, <a href="/search/astro-ph?searchtype=author&query=Stocke%2C+J">John Stocke</a>, <a href="/search/astro-ph?searchtype=author&query=Lehner%2C+N">Nicolas Lehner</a>, <a href="/search/astro-ph?searchtype=author&query=Howk%2C+C">Christopher Howk</a>, <a href="/search/astro-ph?searchtype=author&query=Froning%2C+C">Cynthia Froning</a>, <a href="/search/astro-ph?searchtype=author&query=Green%2C+J">James Green</a>, <a href="/search/astro-ph?searchtype=author&query=Oliveira%2C+C">Cristina Oliveira</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Blair%2C+B">Bill Blair</a>, <a href="/search/astro-ph?searchtype=author&query=Kruk%2C+J">Jeff Kruk</a>, <a href="/search/astro-ph?searchtype=author&query=Sonneborn%2C+G">George Sonneborn</a>, <a href="/search/astro-ph?searchtype=author&query=Penton%2C+S">Steven Penton</a>, <a href="/search/astro-ph?searchtype=author&query=Wakker%2C+B">Bart Wakker</a>, <a href="/search/astro-ph?searchtype=author&query=Prochaska%2C+X">Xavier Prochaska</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="1209.3272v1-abstract-short" style="display: inline;"> There is unique and groundbreaking science to be done with a new generation of UV spectrographs that cover wavelengths in the "Lyman Ultraviolet" (LUV; 912 - 1216 Ang). There is no astrophysical basis for truncating spectroscopic wavelength coverage anywhere between the atmospheric cutoff (3100 Ang) and the Lyman limit (912 Ang); the usual reasons this happens are all technical. The unique science… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.3272v1-abstract-full').style.display = 'inline'; document.getElementById('1209.3272v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1209.3272v1-abstract-full" style="display: none;"> There is unique and groundbreaking science to be done with a new generation of UV spectrographs that cover wavelengths in the "Lyman Ultraviolet" (LUV; 912 - 1216 Ang). There is no astrophysical basis for truncating spectroscopic wavelength coverage anywhere between the atmospheric cutoff (3100 Ang) and the Lyman limit (912 Ang); the usual reasons this happens are all technical. The unique science available in the LUV includes critical problems in astrophysics ranging from the habitability of exoplanets to the reionization of the IGM. Crucially, the local Universe (z <= 0.1) is entirely closed to many key physical diagnostics without access to the LUV. These compelling scientific problems require overcoming these technical barriers so that future UV spectrographs can extend coverage to the Lyman limit at 912 Ang. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.3272v1-abstract-full').style.display = 'none'; document.getElementById('1209.3272v1-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 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2012. </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">Science white paper submitted to NASA Solicitation NNH12ZDA008L: Science Objectives and Requirements for the Next NASA UV/Visible Astrophysics Mission Concepts. 6 pages PDF</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1207.6988">arXiv:1207.6988</a> <span> [<a href="https://arxiv.org/pdf/1207.6988">pdf</a>, <a href="https://arxiv.org/ps/1207.6988">ps</a>, <a href="https://arxiv.org/format/1207.6988">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2012.21799.x">10.1111/j.1365-2966.2012.21799.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating the spectroscopic, magnetic and circumstellar variability of the O9 subgiant star HD 57682 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Grunhut%2C+J+H">J. H. Grunhut</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">C. Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Ignace%2C+R">R. Ignace</a>, <a href="/search/astro-ph?searchtype=author&query=Marcolino%2C+W+L+F">W. L. F. Marcolino</a>, <a href="/search/astro-ph?searchtype=author&query=Rivinius%2C+T">Th. Rivinius</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">L. Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Mauclaire%2C+B">B. Mauclaire</a>, <a href="/search/astro-ph?searchtype=author&query=Buil%2C+C">C. Buil</a>, <a href="/search/astro-ph?searchtype=author&query=Garrel%2C+T">T. Garrel</a>, <a href="/search/astro-ph?searchtype=author&query=Ribeiro%2C+J">J. Ribeiro</a>, <a href="/search/astro-ph?searchtype=author&query=Ubaud%2C+S">S. Ubaud</a>, <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+t+M">the MiMeS Collaboration</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="1207.6988v1-abstract-short" style="display: inline;"> The O9IV star HD 57682, discovered to be magnetic within the context of the MiMeS survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this select group, it stands out due to its sharp-lined photospheric spectrum. Since its discovery, the MiMeS Collaboration has continued to obtain spectroscopic and magnetic observations in order to refine our knowledge of its ma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1207.6988v1-abstract-full').style.display = 'inline'; document.getElementById('1207.6988v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1207.6988v1-abstract-full" style="display: none;"> The O9IV star HD 57682, discovered to be magnetic within the context of the MiMeS survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this select group, it stands out due to its sharp-lined photospheric spectrum. Since its discovery, the MiMeS Collaboration has continued to obtain spectroscopic and magnetic observations in order to refine our knowledge of its magnetic field strength and geometry, rotational period, and spectral properties and variability. In this paper we report new ESPaDOnS spectropolarimetric observations of HD 57682, which are combined with previously published ESPaDOnS data and archival H伪 spectroscopy. This dataset is used to determine the rotational period (63.5708 \pm 0.0057 d), refine the longitudinal magnetic field variation and magnetic geometry (dipole surface field strength of 880\pm50 G and magnetic obliquity of 79\pm4\circ as measured from the magnetic longitudinal field variations, assuming an inclination of 60\circ), and examine the phase variation of various lines. In particular, we demonstrate that the H伪 equivalent width undergoes a double-wave variation during a single rotation of the star, consistent with the derived magnetic geometry. We group the variable lines into two classes: those that, like H伪, exhibit non-sinusoidal variability, often with multiple maxima during the rotation cycle, and those that vary essentially sinusoidally. Based on our modelling of the H伪 emission, we show that the variability is consistent with emission being generated from an optically thick, flattened distribution of magnetically-confined plasma that is roughly distributed about the magnetic equator. Finally, we discuss our findings in the magnetospheric framework proposed in our earlier study. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1207.6988v1-abstract-full').style.display = 'none'; document.getElementById('1207.6988v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 July, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 19 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/1205.3075">arXiv:1205.3075</a> <span> [<a href="https://arxiv.org/pdf/1205.3075">pdf</a>, <a href="https://arxiv.org/format/1205.3075">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/10.1051/0004-6361/201118594">10.1051/0004-6361/201118594 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Properties of Galactic early-type O-supergiants: A combined FUV-UV and optical analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Hillier%2C+D+J">D. J. Hillier</a>, <a href="/search/astro-ph?searchtype=author&query=Lanz%2C+T">T. Lanz</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</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="1205.3075v1-abstract-short" style="display: inline;"> We aim to constrain the properties and evolutionary status of early and mid-spectral type supergiants (from O4 to O7.5). These posses the highest mass-loss rates among the O stars, and exhibit conspicuous wind profiles. Using the non-LTE wind code CMFGEN, we simultaneously analyzed the FUV-UV and optical spectral range to determine the photospheric properties and wind parameters. We derived effect… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.3075v1-abstract-full').style.display = 'inline'; document.getElementById('1205.3075v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1205.3075v1-abstract-full" style="display: none;"> We aim to constrain the properties and evolutionary status of early and mid-spectral type supergiants (from O4 to O7.5). These posses the highest mass-loss rates among the O stars, and exhibit conspicuous wind profiles. Using the non-LTE wind code CMFGEN, we simultaneously analyzed the FUV-UV and optical spectral range to determine the photospheric properties and wind parameters. We derived effective temperatures, luminosities, surface gravities, surface abundances, mass-loss rates, wind terminal velocities, and clumping filling factors. The supergiants define a very clear evolutionary sequence, in terms of ages and masses, from younger and more massive stars to older stars with lower initial masses. O4 supergiants cluster around the 3 Myr isochrone and are more massive than 60 Msun, while the O5 to O7.5 stars have masses in the range 50 - 40 Msun and are 4 +/- 0.3 Myr old. The surface chemical composition is typical of evolved O supergiants (nitrogen-rich, carbon- and oxygen-poor). While the observed ranges of carbon and nitrogen mass-fractions are compatible with those expected from evolutionary models for the measured stellar masses, the N/C ratios as a function of age are inconsistent with the theoretical predictions for the four earliest (O4 spectral type) stars of the sample. We question the efficiency of rotational mixing as a function of age for these stars and suggest that another mechanism may be needed to explain the observed abundance patterns. Mass-loss rates derived with clumped-models range within a factor of three of the theoretical mass-loss rates. The corresponding volume-filling factors associated with small-scale clumping are 0.05 +/- 0.02. Clumping is found to start close to the photosphere for all but three stars, two of which are fast rotators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1205.3075v1-abstract-full').style.display = 'none'; document.getElementById('1205.3075v1-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 May, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 11 figures, accepted for publication in A&A 2012</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1202.6041">arXiv:1202.6041</a> <span> [<a href="https://arxiv.org/pdf/1202.6041">pdf</a>, <a href="https://arxiv.org/ps/1202.6041">ps</a>, <a href="https://arxiv.org/format/1202.6041">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2012.20820.x">10.1111/j.1365-2966.2012.20820.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HST/STIS spectroscopy of the magnetic Of?p star HD 108: the low state at ultraviolet wavelengths </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marcolino%2C+W+L+F">W. L. F. Marcolino</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a>, <a href="/search/astro-ph?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/astro-ph?searchtype=author&query=Naze%2C+Y">Y. Naze</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Hillier%2C+D+J">D. J. Hillier</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</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="1202.6041v1-abstract-short" style="display: inline;"> We present the first ultraviolet spectrum of the peculiar, magnetic Of?p star HD 108 obtained in its spectroscopic low state. The new data, obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, reveal significant changes compared to IUE spectra obtained in the high state: N V 1240, Si IV 1400, and C IV 1550 present weaker P-Cygni profiles (less absorption) in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1202.6041v1-abstract-full').style.display = 'inline'; document.getElementById('1202.6041v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1202.6041v1-abstract-full" style="display: none;"> We present the first ultraviolet spectrum of the peculiar, magnetic Of?p star HD 108 obtained in its spectroscopic low state. The new data, obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, reveal significant changes compared to IUE spectra obtained in the high state: N V 1240, Si IV 1400, and C IV 1550 present weaker P-Cygni profiles (less absorption) in the new data, while N IV 1718 absorption is deeper, without the clear wind signature evident in the high state. Such changes contrast with those found in other magnetic massive stars, where more absorption is observed in the resonance doublets when the sightline is close to the plane of the magnetic equator. The new data show also that the photospheric Fe IV forest, at 1600--1700 angstroms, has strengthened compared to previous observations. The ultraviolet variability is large compared to that found in typical, non-magnetic O stars, but moderate when compared to the high-/low-state changes reported in the optical spectrum of HD 108 over several decades. We use non-LTE expanding-atmosphere models to analyze the new STIS observations. Overall, the results are in accord with a scenario in which the optical variability is mainly produced by magnetically constrained gas, close to the photosphere. The relatively modest changes found in the main ultraviolet wind lines suggest that the stellar wind is not substantially variable on a global scale. Nonetheless, multidimensional radiative-transfer models may be needed to understand some of the phenomena observed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1202.6041v1-abstract-full').style.display = 'none'; document.getElementById('1202.6041v1-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 February, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2012. </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">9 pages, 8 figures, accepted for publication in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 422, 2314-2321 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1106.3008">arXiv:1106.3008</a> <span> [<a href="https://arxiv.org/pdf/1106.3008">pdf</a>, <a href="https://arxiv.org/ps/1106.3008">ps</a>, <a href="https://arxiv.org/format/1106.3008">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2011.19265.x">10.1111/j.1365-2966.2011.19265.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Confirmation of the magnetic oblique rotator model for the Of?p star HD 191612 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/astro-ph?searchtype=author&query=Townsend%2C+R+H+D">R. H. D. Townsend</a>, <a href="/search/astro-ph?searchtype=author&query=Grunhut%2C+J+H">J. H. Grunhut</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M">M. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Marcolino%2C+W">W. Marcolino</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Y. Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Doula%2C+A+u">A. ud Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a>, <a href="/search/astro-ph?searchtype=author&query=Donati%2C+J+-">J. -F. Donati</a>, <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+t+M">the MiMeS Collaboration</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="1106.3008v1-abstract-short" style="display: inline;"> This paper reports high-precision Stokes V spectra of HD 191612 acquired using the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope, in the context of the Magnetism in Massive stars (MiMeS) Project. Using measurements of the equivalent width of the Halpha line and radial velocities of various metallic lines, we have updated both the spectroscopic and orbital ephemerides of this st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1106.3008v1-abstract-full').style.display = 'inline'; document.getElementById('1106.3008v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1106.3008v1-abstract-full" style="display: none;"> This paper reports high-precision Stokes V spectra of HD 191612 acquired using the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope, in the context of the Magnetism in Massive stars (MiMeS) Project. Using measurements of the equivalent width of the Halpha line and radial velocities of various metallic lines, we have updated both the spectroscopic and orbital ephemerides of this star. We confirm the presence of a strong magnetic field in the photosphere of HD 191612, and detect its variability. We establish that the longitudinal field varies in a manner consistent with the spectroscopic period of 537.6 d, in an approximately sinusoidal fashion. This demonstrates a firm connection between the magnetic field and the processes responsible for the line and continuum variability. Interpreting the variation of the longitudinal magnetic field within the context of the dipole oblique rotator model we obtain a best-fit surface magnetic field model with obliquity beta=67\pm 5 deg and polar strength Bd=2450\pm 400 G . The inferred magnetic field strength implies an equatorial wind magnetic confinement parameter eta*~50, supporting a picture in which the Halpha emission and photometric variability have their origin in an oblique, rigidly rotating magnetospheric structure resulting from a magnetically channeled wind. This interpretation is supported by our successful Monte Carlo radiative transfer modeling of the photometric variation, which assumes the enhanced plasma densities in the magnetic equatorial plane above the star implied by such a picture. Predictions of the continuum linear polarisation resulting from Thompson scattering from the magnetospheric material indicate that the Stokes Q and U variations are highly sensitive to the magnetospheric geometry, and that expected amplitudes are in the range of current instrumentation. (abridged) <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1106.3008v1-abstract-full').style.display = 'none'; document.getElementById('1106.3008v1-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> 15 June, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, accepted by MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 416, 3160-3169 (2011) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1104.4810">arXiv:1104.4810</a> <span> [<a href="https://arxiv.org/pdf/1104.4810">pdf</a>, <a href="https://arxiv.org/ps/1104.4810">ps</a>, <a href="https://arxiv.org/format/1104.4810">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/10.1088/0004-6256/142/1/21">10.1088/0004-6256/142/1/21 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An Interferometric and Spectroscopic Analysis of the Multiple Star System HD 193322 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Brummelaar%2C+T+A+t">Theo A. ten Brummelaar</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Brien%2C+D+P">David P. O'Brien</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+B+D">Brian D. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Farrington%2C+C+D">Christopher D. Farrington</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gies%2C+D+R">Douglas R. Gies</a>, <a href="/search/astro-ph?searchtype=author&query=Grundstrom%2C+E+D">Erika D. Grundstrom</a>, <a href="/search/astro-ph?searchtype=author&query=Hartkopf%2C+W+I">William I. Hartkopf</a>, <a href="/search/astro-ph?searchtype=author&query=Matson%2C+R+A">Rachel A. Matson</a>, <a href="/search/astro-ph?searchtype=author&query=McAlister%2C+H+A">Harold A. McAlister</a>, <a href="/search/astro-ph?searchtype=author&query=McSwain%2C+M+V">M. Virginia McSwain</a>, <a href="/search/astro-ph?searchtype=author&query=Roberts%2C%2C+L+C">Lewis C. Roberts, Jr.</a>, <a href="/search/astro-ph?searchtype=author&query=Schaefer%2C+G+H">Gail H. Schaefer</a>, <a href="/search/astro-ph?searchtype=author&query=Simon-Diaz%2C+S">Sergio Simon-Diaz</a>, <a href="/search/astro-ph?searchtype=author&query=Sturmann%2C+J">Judit Sturmann</a>, <a href="/search/astro-ph?searchtype=author&query=Sturmann%2C+L">Laszlo Sturmann</a>, <a href="/search/astro-ph?searchtype=author&query=Turner%2C+N+H">Nils H. Turner</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+S+J">Stephen J. Williams</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="1104.4810v2-abstract-short" style="display: inline;"> The star HD 193322 is a remarkable multiple system of massive stars that lies at the heart of the cluster Collinder 419. Here we report on new spectroscopic observations and radial velocities of the narrow-lined component Ab1 that we use to determine its orbital motion around a close companion Ab2 ($P = 312$ d) and around a distant third star Aa ($P = 35$ y).We have also obtained long baseline int… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1104.4810v2-abstract-full').style.display = 'inline'; document.getElementById('1104.4810v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1104.4810v2-abstract-full" style="display: none;"> The star HD 193322 is a remarkable multiple system of massive stars that lies at the heart of the cluster Collinder 419. Here we report on new spectroscopic observations and radial velocities of the narrow-lined component Ab1 that we use to determine its orbital motion around a close companion Ab2 ($P = 312$ d) and around a distant third star Aa ($P = 35$ y).We have also obtained long baseline interferometry of the target in the $K^\prime$-band with the CHARA Array that we use in two ways. First, we combine published speckle interferometric measurements with CHARA separated fringe packet measurements to improve the visual orbit for the wide Aa,Ab binary. Second, we use measurements of the fringe packet from Aa to calibrate the visibility of the fringes of the Ab1,Ab2 binary, and we analyze these fringe visibilities to determine the visual orbit of the close system. The two most massive stars, Aa and Ab1, have masses of approximately 21 and $23 M_\odot$, respectively, and their spectral line broadening indicates that they represent extremes of fast and slow projected rotational velocity, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1104.4810v2-abstract-full').style.display = 'none'; document.getElementById('1104.4810v2-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 April, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 April, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2011. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1104.4786">arXiv:1104.4786</a> <span> [<a href="https://arxiv.org/pdf/1104.4786">pdf</a>, <a href="https://arxiv.org/ps/1104.4786">ps</a>, <a href="https://arxiv.org/format/1104.4786">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2011.18952.x">10.1111/j.1365-2966.2011.18952.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chandra X-ray spectroscopy of the very early O supergiant HD 93129A: constraints on wind shocks and the mass-loss rate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">David H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Gagn%C3%A9%2C+M">Marc Gagn茅</a>, <a href="/search/astro-ph?searchtype=author&query=Leutenegger%2C+M+A">Maurice A. Leutenegger</a>, <a href="/search/astro-ph?searchtype=author&query=MacArthur%2C+J+P">James P. MacArthur</a>, <a href="/search/astro-ph?searchtype=author&query=Wollman%2C+E+E">Emma E. Wollman</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alex W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">Stanley P. Owocki</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="1104.4786v1-abstract-short" style="display: inline;"> We present analysis of both the resolved X-ray emission line profiles and the broadband X-ray spectrum of the O2 If* star HD 93129A, measured with the Chandra HETGS. This star is among the earliest and most massive stars in the Galaxy, and provides a test of the embedded wind shock scenario in a very dense and powerful wind. A major new result is that continuum absorption by the dense wind is the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1104.4786v1-abstract-full').style.display = 'inline'; document.getElementById('1104.4786v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1104.4786v1-abstract-full" style="display: none;"> We present analysis of both the resolved X-ray emission line profiles and the broadband X-ray spectrum of the O2 If* star HD 93129A, measured with the Chandra HETGS. This star is among the earliest and most massive stars in the Galaxy, and provides a test of the embedded wind shock scenario in a very dense and powerful wind. A major new result is that continuum absorption by the dense wind is the primary cause of the hardness of the observed X-ray spectrum, while intrinsically hard emission from colliding wind shocks contributes less than 10% of the X-ray flux. We find results consistent with the predictions of numerical simulations of the line-driving instability, including line broadening indicating an onset radius of X-ray emission of several tenths Rstar. Helium-like forbidden-to-intercombination line ratios are consistent with this onset radius, and inconsistent with being formed in a wind-collision interface with the star's closest visual companion at a distance of ~100 AU. The broadband X-ray spectrum is fit with a dominant emission temperature of just kT = 0.6 keV along with significant wind absorption. The broadband wind absorption and the line profiles provide two independent measurements of the wind mass-loss rate: Mdot = 5.2_{-1.5}^{+1.8} \times 10^{-6} Msun/yr and Mdot = 6.8_{-2.2}^{+2.8} \times 10^{-6} Msun/yr, respectively. This is the first consistent modeling of the X-ray line profile shapes and broadband X-ray spectral energy distribution in a massive star, and represents a reduction of a factor of 3 to 4 compared to the standard H-alpha mass-loss rate that assumes a smooth wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1104.4786v1-abstract-full').style.display = 'none'; document.getElementById('1104.4786v1-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 April, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Monthly Notices of the Royal Astronomical Society. 12 pages, 10 figures (incl. 5 color)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1010.3387">arXiv:1010.3387</a> <span> [<a href="https://arxiv.org/pdf/1010.3387">pdf</a>, <a href="https://arxiv.org/ps/1010.3387">ps</a>, <a href="https://arxiv.org/format/1010.3387">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Mass loss rates inferred from mid-IR color excesses of LMC and SMC O stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D">D. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</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="1010.3387v1-abstract-short" style="display: inline;"> We use a combination of VJHK and Spitzer} [3.6], [5.8] and [8.0] photometry, to determine IR excesses in a sample of LMC and SMC O stars. This sample is ideal for determining excesses because: 1) the distances to the stars, and hence their luminosities, are well-determined, and; 2) the very small line of sight reddenings minimize the uncertainties introduced by extinction corrections. We find IR e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.3387v1-abstract-full').style.display = 'inline'; document.getElementById('1010.3387v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1010.3387v1-abstract-full" style="display: none;"> We use a combination of VJHK and Spitzer} [3.6], [5.8] and [8.0] photometry, to determine IR excesses in a sample of LMC and SMC O stars. This sample is ideal for determining excesses because: 1) the distances to the stars, and hence their luminosities, are well-determined, and; 2) the very small line of sight reddenings minimize the uncertainties introduced by extinction corrections. We find IR excesses much larger than expected from Vink et al. (2001) mass loss rates. This is in contrast to previous wind line analyses for many of the LMC stars which suggest mass loss rates much less than the Vink et al. predictions. ogether, these results indicate that the winds of the LMC and SMC O stars are strongly structured (clumped). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.3387v1-abstract-full').style.display = 'none'; document.getElementById('1010.3387v1-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> 16 October, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2010. </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">2 pages, 2 figures; to appear in the proceedings of IAU Symposium 272</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1010.2224">arXiv:1010.2224</a> <span> [<a href="https://arxiv.org/pdf/1010.2224">pdf</a>, <a href="https://arxiv.org/ps/1010.2224">ps</a>, <a href="https://arxiv.org/format/1010.2224">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</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/10.1017/S1743921311010246">10.1017/S1743921311010246 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Is the Wind of the Galactic Oe Star HD 155806 Magnetically Confined? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">S. Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Collaboration%2C+t+M">the MiMeS Collaboration</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="1010.2224v1-abstract-short" style="display: inline;"> Spectropolarimetric observations of HD 155806 - the hottest Galactic Oe star - were obtained with CFHT/ESPaDOnS to test the hypothesis that disk signatures in its spectrum are due to magnetic channeling and confinement of its stellar wind. We did not detect a dipole field of sufficient strength to confine the wind, and could not confirm previous reports of a magnetic detection. It appears that ste… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.2224v1-abstract-full').style.display = 'inline'; document.getElementById('1010.2224v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1010.2224v1-abstract-full" style="display: none;"> Spectropolarimetric observations of HD 155806 - the hottest Galactic Oe star - were obtained with CFHT/ESPaDOnS to test the hypothesis that disk signatures in its spectrum are due to magnetic channeling and confinement of its stellar wind. We did not detect a dipole field of sufficient strength to confine the wind, and could not confirm previous reports of a magnetic detection. It appears that stellar magnetism is not responsible for producing the disk of HD 155806. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1010.2224v1-abstract-full').style.display = 'none'; document.getElementById('1010.2224v1-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 October, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2010. </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">2 pages, 1 figure; to appear in the proceedings of IAU Symposium 272</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0904.2003">arXiv:0904.2003</a> <span> [<a href="https://arxiv.org/pdf/0904.2003">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> From Protostars to Planetary Systems : FUV Spectroscopy of YSOs, Protoplanetary Disks, and Extrasolar Giant Planets </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Scowen%2C+P+A">Paul A. Scowen</a>, <a href="/search/astro-ph?searchtype=author&query=Jansen%2C+R">Rolf Jansen</a>, <a href="/search/astro-ph?searchtype=author&query=Beasley%2C+M">Matthew Beasley</a>, <a href="/search/astro-ph?searchtype=author&query=Desch%2C+S">Steve Desch</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=McCaughrean%2C+M">Mark McCaughrean</a>, <a href="/search/astro-ph?searchtype=author&query=Oey%2C+S">Sally Oey</a>, <a href="/search/astro-ph?searchtype=author&query=Padgett%2C+D">Debbie Padgett</a>, <a href="/search/astro-ph?searchtype=author&query=Roberge%2C+A">Aki Roberge</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+N">Nathan Smith</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="0904.2003v1-abstract-short" style="display: inline;"> The last two decades have seen remarkable progress in our long-standing goal of determining the abundance and diversity of worlds in the Galaxy. Understanding of this subject involves tracing the path of interstellar material from dense cloud cores, to young stellar objects, protoplanetary disks, and finally extrasolar planets. Here we discuss the critical information provided on these objects b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.2003v1-abstract-full').style.display = 'inline'; document.getElementById('0904.2003v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0904.2003v1-abstract-full" style="display: none;"> The last two decades have seen remarkable progress in our long-standing goal of determining the abundance and diversity of worlds in the Galaxy. Understanding of this subject involves tracing the path of interstellar material from dense cloud cores, to young stellar objects, protoplanetary disks, and finally extrasolar planets. Here we discuss the critical information provided on these objects by point-source far-ultraviolet spectroscopy with a large aperture, high resolution spectrograph of a large sample of unique protostellar and protoplanetary objects that will leverage our existing knowledge to lay out a path to new and powerful insight into the formation process. We lay out a systematic case of coordinated observations that will yield new knowledge about the process of assembly for both protostellar and protoplanetary systems - that addresses specific uncertainties in our current knowledge and takes advantage of potential new technologies to acquire the data needed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.2003v1-abstract-full').style.display = 'none'; document.getElementById('0904.2003v1-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> 13 April, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2009. </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 - Science White Paper for the Astro2010 Decadal Survey Panel(s): Planetary Systems and Star Formation</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0904.1992">arXiv:0904.1992</a> <span> [<a href="https://arxiv.org/pdf/0904.1992">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> The Star Formation Camera </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Scowen%2C+P+A">Paul A. Scowen</a>, <a href="/search/astro-ph?searchtype=author&query=Jansen%2C+R">Rolf Jansen</a>, <a href="/search/astro-ph?searchtype=author&query=Beasley%2C+M">Matthew Beasley</a>, <a href="/search/astro-ph?searchtype=author&query=Calzetti%2C+D">Daniela Calzetti</a>, <a href="/search/astro-ph?searchtype=author&query=Desch%2C+S">Steven Desch</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gallagher%2C+J">John Gallagher</a>, <a href="/search/astro-ph?searchtype=author&query=Lisman%2C+D">Doug Lisman</a>, <a href="/search/astro-ph?searchtype=author&query=Macenka%2C+S">Steve Macenka</a>, <a href="/search/astro-ph?searchtype=author&query=Malhotra%2C+S">Sangeeta Malhotra</a>, <a href="/search/astro-ph?searchtype=author&query=McCaughrean%2C+M">Mark McCaughrean</a>, <a href="/search/astro-ph?searchtype=author&query=Nikzad%2C+S">Shouleh Nikzad</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Connell%2C+R">Robert O'Connell</a>, <a href="/search/astro-ph?searchtype=author&query=Oey%2C+S">Sally Oey</a>, <a href="/search/astro-ph?searchtype=author&query=Padgett%2C+D">Deborah Padgett</a>, <a href="/search/astro-ph?searchtype=author&query=Rhoads%2C+J">James Rhoads</a>, <a href="/search/astro-ph?searchtype=author&query=Roberge%2C+A">Aki Roberge</a>, <a href="/search/astro-ph?searchtype=author&query=Siegmund%2C+O">Oswald Siegmund</a>, <a href="/search/astro-ph?searchtype=author&query=Shaklan%2C+S">Stuart Shaklan</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+N">Nathan Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Stern%2C+D">Daniel Stern</a>, <a href="/search/astro-ph?searchtype=author&query=Tumlinson%2C+J">Jason Tumlinson</a>, <a href="/search/astro-ph?searchtype=author&query=Windhorst%2C+R">Rogier Windhorst</a>, <a href="/search/astro-ph?searchtype=author&query=Woodruff%2C+R">Robert Woodruff</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="0904.1992v1-abstract-short" style="display: inline;"> The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.1992v1-abstract-full').style.display = 'inline'; document.getElementById('0904.1992v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0904.1992v1-abstract-full" style="display: none;"> The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems, and to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process. This program addresses the origins and evolution of stars, galaxies, and cosmic structure and has direct relevance for the formation and survival of planetary systems like our Solar System and planets like Earth. We present the design and performance specifications resulting from the implementation study of the camera, conducted under NASA's Astrophysics Strategic Mission Concept Studies program, which is intended to assemble realistic options for mission development over the next decade. The result is an extraordinarily capable instrument that will provide deep, high-resolution imaging across a very wide field enabling a great variety of community science as well as completing the core survey science that drives the design of the camera. The technology associated with the camera is next generation but still relatively high TRL, allowing a low-risk solution with moderate technology development investment over the next 10 years. We estimate the cost of the instrument to be $390M FY08. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.1992v1-abstract-full').style.display = 'none'; document.getElementById('0904.1992v1-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> 13 April, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2009. </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 - Activity White Paper for the Astro2010 Decadal Survey Subcommittee on Programs</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0904.1987">arXiv:0904.1987</a> <span> [<a href="https://arxiv.org/pdf/0904.1987">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> </div> </div> <p class="title is-5 mathjax"> The Magellanic Clouds Survey: a Bridge to Nearby Galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Scowen%2C+P+A">Paul A. Scowen</a>, <a href="/search/astro-ph?searchtype=author&query=Jansen%2C+R">Rolf Jansen</a>, <a href="/search/astro-ph?searchtype=author&query=Beasley%2C+M">Matthew Beasley</a>, <a href="/search/astro-ph?searchtype=author&query=Calzetti%2C+D">Daniela Calzetti</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alex Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Gallagher%2C+J">John Gallagher</a>, <a href="/search/astro-ph?searchtype=author&query=McCaughrean%2C+M">Mark McCaughrean</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Connell%2C+R">Robert O'Connell</a>, <a href="/search/astro-ph?searchtype=author&query=Oey%2C+S">Sally Oey</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+N">Nathan Smith</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="0904.1987v1-abstract-short" style="display: inline;"> We outline to the community the value of a Magellanic Clouds Survey that consists of three components: I) a complete-area, high resolution, multi-band UV-near-IR broadband survey; II) a narrowband survey in 7 key nebular filters to cover a statistically significant sample of representative HII regions and a large-area, contiguous survey of the diffuse, warm ISM; and III) a comprehensive FUV spec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.1987v1-abstract-full').style.display = 'inline'; document.getElementById('0904.1987v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0904.1987v1-abstract-full" style="display: none;"> We outline to the community the value of a Magellanic Clouds Survey that consists of three components: I) a complete-area, high resolution, multi-band UV-near-IR broadband survey; II) a narrowband survey in 7 key nebular filters to cover a statistically significant sample of representative HII regions and a large-area, contiguous survey of the diffuse, warm ISM; and III) a comprehensive FUV spectroscopic survey of 1300 early-type stars. The science areas enabled by such a dataset are as follows: A) assessment of massive star feedback in both HII regions and the diffuse, warm ISM; B) completion of a comprehensive study of the 30 Doradus giant extragalactic HII region (GEHR); C) development and quantitative parameterization of stellar clustering properties; D) extensive FUV studies of early-type stellar atmospheres and their energy distributions; and E) similarly extensive FUV absorption-line studies of molecular cloud structure and ISM extinction properties. These data will also allow a number of additional studies relating to the underlying stellar populations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0904.1987v1-abstract-full').style.display = 'none'; document.getElementById('0904.1987v1-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> 13 April, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2009. </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 - Science White Paper for the Astro2010 Decadal Survey Panel(s): Planetary Systems and Star Formation; Stars and Stellar Evolution; the Galactic Neighborhood</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0812.2464">arXiv:0812.2464</a> <span> [<a href="https://arxiv.org/pdf/0812.2464">pdf</a>, <a href="https://arxiv.org/ps/0812.2464">ps</a>, <a href="https://arxiv.org/format/0812.2464">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1017/S1743921309030786">10.1017/S1743921309030786 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Is the wind of the Oe star HD 155806 magnetically confined? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">S. Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</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="0812.2464v1-abstract-short" style="display: inline;"> Oe stars are a subset of the O-type stars that exhibit emission lines from a circumstellar disk. The recent detection of magnetic fields in some O-type stars suggests a possible explanation for the stability of disk-like structures around Oe stars. According to this hypothesis, the wind of the star is channeled by a dipolar magnetic field producing a disc in the magnetic equatorial plane. As a t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.2464v1-abstract-full').style.display = 'inline'; document.getElementById('0812.2464v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0812.2464v1-abstract-full" style="display: none;"> Oe stars are a subset of the O-type stars that exhibit emission lines from a circumstellar disk. The recent detection of magnetic fields in some O-type stars suggests a possible explanation for the stability of disk-like structures around Oe stars. According to this hypothesis, the wind of the star is channeled by a dipolar magnetic field producing a disc in the magnetic equatorial plane. As a test of this model, we have obtained spectropolarimetric observations of the hottest Galactic Oe star HD 155806. Here we discuss the results and implications of those observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.2464v1-abstract-full').style.display = 'none'; document.getElementById('0812.2464v1-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 December, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2008. </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">2 pages, 1 figure. Proceedings IAU Symposium No. 259, 2009. Cosmic Magnetic Fields: From Planets, to Stars and Galaxies</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0711.4858">arXiv:0711.4858</a> <span> [<a href="https://arxiv.org/pdf/0711.4858">pdf</a>, <a href="https://arxiv.org/ps/0711.4858">ps</a>, <a href="https://arxiv.org/format/0711.4858">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> </div> <p class="title is-5 mathjax"> New insights into the nature of the SMC WR/LBV binary HD 5980 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Foellmi%2C+C">C. Foellmi</a>, <a href="/search/astro-ph?searchtype=author&query=Koenigsberger%2C+G">G. Koenigsberger</a>, <a href="/search/astro-ph?searchtype=author&query=Georgiev%2C+L">L. Georgiev</a>, <a href="/search/astro-ph?searchtype=author&query=Toledano%2C+O">O. Toledano</a>, <a href="/search/astro-ph?searchtype=author&query=Marchenko%2C+S+V">S. V. Marchenko</a>, <a href="/search/astro-ph?searchtype=author&query=Massey%2C+P">P. Massey</a>, <a href="/search/astro-ph?searchtype=author&query=Dall%2C+T+H">T. H. Dall</a>, <a href="/search/astro-ph?searchtype=author&query=Moffat%2C+A+F+J">A. F. J. Moffat</a>, <a href="/search/astro-ph?searchtype=author&query=Morrell%2C+N">N. Morrell</a>, <a href="/search/astro-ph?searchtype=author&query=Corcoran%2C+M">M. Corcoran</a>, <a href="/search/astro-ph?searchtype=author&query=Kaufer%2C+A">A. Kaufer</a>, <a href="/search/astro-ph?searchtype=author&query=Naze%2C+Y">Y. Naze</a>, <a href="/search/astro-ph?searchtype=author&query=Pittard%2C+J">J. Pittard</a>, <a href="/search/astro-ph?searchtype=author&query=-Louis%2C+N+S">N. St. -Louis</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">A. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Pollock%2C+A+M+T">A. M. T. Pollock</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="0711.4858v1-abstract-short" style="display: inline;"> We present the results of optical wavelength observations of the unusual SMC eclipsing binary system HD 5980 obtained in 1999 and 2004--2005. Radial velocity curves for the erupting LBV/WR object (star A) and its close WR-like companion (star B) are obtained by deblending the variable emission-line profiles of N IV and N V lines under the simplistic assumption that these lines originate primaril… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.4858v1-abstract-full').style.display = 'inline'; document.getElementById('0711.4858v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0711.4858v1-abstract-full" style="display: none;"> We present the results of optical wavelength observations of the unusual SMC eclipsing binary system HD 5980 obtained in 1999 and 2004--2005. Radial velocity curves for the erupting LBV/WR object (star A) and its close WR-like companion (star B) are obtained by deblending the variable emission-line profiles of N IV and N V lines under the simplistic assumption that these lines originate primarily in the winds of star A and star B. The derived masses M_A=58--79 Mo and M_B=51--67 Mo, are more consistent with the stars' location near the top of the HRD than previous estimates. The presence of a wind-wind interaction region is inferred from the orbital phase-dependent behavior of He I P Cygni absorption components. The emission-line intensities continued with the declining trend previously seen in UV spectra. The behavior of the photospheric absorption lines is consistent with the results of Schweickhardt (2002) who concludes that the third object in the combined spectrum, star C, is also a binary system with P(starC)~96.5 days, e=0.83. The data used in this paper will be made publicly available for further analysis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.4858v1-abstract-full').style.display = 'none'; document.getElementById('0711.4858v1-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 November, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2007. </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">48 pages, 26 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Rev.Mex.Astron.Astrofis.44:3-27,2008 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0708.2350">arXiv:0708.2350</a> <span> [<a href="https://arxiv.org/pdf/0708.2350">pdf</a>, <a href="https://arxiv.org/ps/0708.2350">ps</a>, <a href="https://arxiv.org/format/0708.2350">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1111/j.1365-2966.2007.12360.x">10.1111/j.1365-2966.2007.12360.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Structure and clumping in the fast wind of NGC6543 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Hodges%2C+S+E">S. E. Hodges</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D+L">D. L. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Burnley%2C+A+W">A. W. Burnley</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="0708.2350v1-abstract-short" style="display: inline;"> Far-UV spectroscopy from the FUSE satellite is analysed to uniquely probe spatial structure and clumping in the fast wind of the central star of the H-rich planetary nebula NGC6543 (HD164963). Time-series data of the unsaturated PV 1118, 1128 resonance line P Cygni profiles provide a very sensitive diagnostic of variable wind conditions in the outflow. We report on the discovery of episodic and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0708.2350v1-abstract-full').style.display = 'inline'; document.getElementById('0708.2350v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0708.2350v1-abstract-full" style="display: none;"> Far-UV spectroscopy from the FUSE satellite is analysed to uniquely probe spatial structure and clumping in the fast wind of the central star of the H-rich planetary nebula NGC6543 (HD164963). Time-series data of the unsaturated PV 1118, 1128 resonance line P Cygni profiles provide a very sensitive diagnostic of variable wind conditions in the outflow. We report on the discovery of episodic and recurrent optical depth enhancements in the PV absorption troughs, with some evidence for a 0.17-day modulation time-scale. SEI line-synthesis modelling is used to derive physical properties, including the optical depth evolution of individual `events'. The characteristics of these features are essentially identical to the `discrete absorption components' (DACs) commonly seen in the UV lines of massive OB stars. We have also employed the unified model atmosphere code CMFGEN to explore spectroscopic signatures of clumping, and report in particular on the clear sensitivity of the PV lines to the clump volume filling factor. The results presented here have implications for the downward revision of mass-loss rates in PN central stars. We conclude that the temporal structures seen in the PV lines of NGC6543 likely have a physical origin that is similar to that operating in massive, luminous stars, and may be related to near-surface perturbations caused by stellar pulsation and/or magnetic fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0708.2350v1-abstract-full').style.display = 'none'; document.getElementById('0708.2350v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 August, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2007. </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, 11 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/0708.0857">arXiv:0708.0857</a> <span> [<a href="https://arxiv.org/pdf/0708.0857">pdf</a>, <a href="https://arxiv.org/ps/0708.0857">ps</a>, <a href="https://arxiv.org/format/0708.0857">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> </div> <p class="title is-5 mathjax"> The effects of clumping on wind line variability </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</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="0708.0857v1-abstract-short" style="display: inline;"> We review the effects of clumping on the profiles of resonance doublets. By allowing the ratio of the doublet oscillator strenghts to be a free parameter, we demonstrate that doublet profiles contain more information than is normally utilized. In clumped (or porous) winds, this ratio can lies between unity and the ratio of the f-values, and can change as a function of velocity and time, dependin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0708.0857v1-abstract-full').style.display = 'inline'; document.getElementById('0708.0857v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0708.0857v1-abstract-full" style="display: none;"> We review the effects of clumping on the profiles of resonance doublets. By allowing the ratio of the doublet oscillator strenghts to be a free parameter, we demonstrate that doublet profiles contain more information than is normally utilized. In clumped (or porous) winds, this ratio can lies between unity and the ratio of the f-values, and can change as a function of velocity and time, depending on the fraction of the stellar disk that is covered by material moving at a particular velocity at a given moment. Using these insights, we present the results of SEI modeling of a sample of B supergiants, zeta Pup and a time series for a star whose terminal velocity is low enough to make the components of its Si IV 1400 doublet independent. These results are interpreted within the framework of the Oskinova et al. (2007) model, and demonstrate how the doublet profiles can be used to extract infromation about wind structure. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0708.0857v1-abstract-full').style.display = 'none'; document.getElementById('0708.0857v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 August, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2007. </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">3 pages, to appear in Clumping in Hot Star Winds, W.-R. Hamann, A. Feldmeier & L. Oskinova, eds., Potsdam: Univ.-Verl., 2007, URN: http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13981</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0704.3229">arXiv:0704.3229</a> <span> [<a href="https://arxiv.org/pdf/0704.3229">pdf</a>, <a href="https://arxiv.org/ps/0704.3229">ps</a>, <a href="https://arxiv.org/format/0704.3229">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/519015">10.1086/519015 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Long Period, Massive Binaries HD 37366 and HD 54662: Potential Targets for Long Baseline Optical Interferometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Boyajian%2C+T+S">T. S. Boyajian</a>, <a href="/search/astro-ph?searchtype=author&query=Gies%2C+D+R">D. R. Gies</a>, <a href="/search/astro-ph?searchtype=author&query=Dunn%2C+J+P">J. P. Dunn</a>, <a href="/search/astro-ph?searchtype=author&query=Farrington%2C+C+D">C. D. Farrington</a>, <a href="/search/astro-ph?searchtype=author&query=Grundstrom%2C+E+D">E. D. Grundstrom</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/astro-ph?searchtype=author&query=McSwain%2C+M+V">M. V. McSwain</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+S+J">S. J. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Wingert%2C+D+W">D. W. Wingert</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Bolton%2C+C+T">C. T. Bolton</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="0704.3229v1-abstract-short" style="display: inline;"> We present the results from an optical spectroscopic analysis of the massive stars HD 37366 and HD 54662. We find that HD 37366 is a double-lined spectroscopic binary with a period of 31.8187 +/- 0.0004 days, and HD 54662 is also a double lined binary with a much longer period of 557.8 +/- 0.3 days. The primary of HD 37366 is classified as O9.5 V, and it contributes approximately two-thirds of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0704.3229v1-abstract-full').style.display = 'inline'; document.getElementById('0704.3229v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0704.3229v1-abstract-full" style="display: none;"> We present the results from an optical spectroscopic analysis of the massive stars HD 37366 and HD 54662. We find that HD 37366 is a double-lined spectroscopic binary with a period of 31.8187 +/- 0.0004 days, and HD 54662 is also a double lined binary with a much longer period of 557.8 +/- 0.3 days. The primary of HD 37366 is classified as O9.5 V, and it contributes approximately two-thirds of the optical flux. The less luminous secondary is a broad-lined, early B-type main-sequence star. Tomographic reconstruction of the individual spectra of HD 37366 reveals absorption lines present in each component, enabling us to constrain the nature of the secondary and physical characteristics of both stars. Tomographic reconstruction was not possible for HD 54662; however, we do present mean spectra from our observations that show that the secondary component is approximately half as bright as the primary. The observed spectral energy distributions (SEDs) were fit with model SEDs and galactic reddening curves to determine the angular sizes of the stars. By assuming radii appropriate for their classifications, we determine distance ranges of 1.4 - 1.9 and 1.2 - 1.5 kpc for HD 37366 and HD 54662, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0704.3229v1-abstract-full').style.display = 'none'; document.getElementById('0704.3229v1-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 April, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2007. </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">27 pages, 8 figures, Accepted for publication in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J.664:1121-1129,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0704.0899">arXiv:0704.0899</a> <span> [<a href="https://arxiv.org/pdf/0704.0899">pdf</a>, <a href="https://arxiv.org/ps/0704.0899">ps</a>, <a href="https://arxiv.org/format/0704.0899">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/518617">10.1086/518617 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CalFUSE v3: A Data-Reduction Pipeline for the Far Ultraviolet Spectroscopic Explorer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dixon%2C+W+V">W. V. Dixon</a>, <a href="/search/astro-ph?searchtype=author&query=Sahnow%2C+D+J">D. J. Sahnow</a>, <a href="/search/astro-ph?searchtype=author&query=Barrett%2C+P+E">P. E. Barrett</a>, <a href="/search/astro-ph?searchtype=author&query=Civeit%2C+T">T. Civeit</a>, <a href="/search/astro-ph?searchtype=author&query=Dupuis%2C+J">J. Dupuis</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Godard%2C+B">B. Godard</a>, <a href="/search/astro-ph?searchtype=author&query=Hsu%2C+J+C">J. C. Hsu</a>, <a href="/search/astro-ph?searchtype=author&query=Kaiser%2C+M+E">M. E. Kaiser</a>, <a href="/search/astro-ph?searchtype=author&query=Kruk%2C+J+W">J. W. Kruk</a>, <a href="/search/astro-ph?searchtype=author&query=Lacour%2C+S">S. Lacour</a>, <a href="/search/astro-ph?searchtype=author&query=Lindler%2C+D+J">D. J. Lindler</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">D. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Robinson%2C+R+D">R. D. Robinson</a>, <a href="/search/astro-ph?searchtype=author&query=Romelfanger%2C+M+L">M. L. Romelfanger</a>, <a href="/search/astro-ph?searchtype=author&query=Sonnentrucker%2C+P">P. Sonnentrucker</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="0704.0899v1-abstract-short" style="display: inline;"> Since its launch in 1999, the Far Ultraviolet Spectroscopic Explorer (FUSE) has made over 4600 observations of some 2500 individual targets. The data are reduced by the Principal Investigator team at the Johns Hopkins University and archived at the Multimission Archive at Space Telescope (MAST). The data-reduction software package, called CalFUSE, has evolved considerably over the lifetime of th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0704.0899v1-abstract-full').style.display = 'inline'; document.getElementById('0704.0899v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0704.0899v1-abstract-full" style="display: none;"> Since its launch in 1999, the Far Ultraviolet Spectroscopic Explorer (FUSE) has made over 4600 observations of some 2500 individual targets. The data are reduced by the Principal Investigator team at the Johns Hopkins University and archived at the Multimission Archive at Space Telescope (MAST). The data-reduction software package, called CalFUSE, has evolved considerably over the lifetime of the mission. The entire FUSE data set has recently been reprocessed with CalFUSE v3.2, the latest version of this software. This paper describes CalFUSE v3.2, the instrument calibrations upon which it is based, and the format of the resulting calibrated data files. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0704.0899v1-abstract-full').style.display = 'none'; document.getElementById('0704.0899v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 April, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2007. </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">To appear in PASP; 29 pages, 13 figures, uses aastex, emulateapj</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0607489">arXiv:astro-ph/0607489</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0607489">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0607489">ps</a>, <a href="https://arxiv.org/format/astro-ph/0607489">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/505519">10.1086/505519 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cepheid Masses: FUSE Observations of S Mus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Evans%2C+N+R">Nancy Remage Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">Derck Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A">Alexander Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Sonneborn%2C+G">George Sonneborn</a>, <a href="/search/astro-ph?searchtype=author&query=Iping%2C+R">Rosina Iping</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="astro-ph/0607489v1-abstract-short" style="display: inline;"> S Mus is the Cepheid with the hottest known companion. The large ultraviolet flux means that it is the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature is difficult to constrain at wavelengths longer than 1200 脜because of the degeneracy between temperature and reddening. We have obtained a FUSE sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0607489v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0607489v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0607489v1-abstract-full" style="display: none;"> S Mus is the Cepheid with the hottest known companion. The large ultraviolet flux means that it is the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature is difficult to constrain at wavelengths longer than 1200 脜because of the degeneracy between temperature and reddening. We have obtained a FUSE spectrum in order to improve the determination of the temperature of the companion. Two regions which are temperature sensitive near 16,000 K but relatively unaffected by H$_2$ absorption (940 脜, and the Ly $尾$ wings) have been identified. By comparing FUSE spectra of S Mus B with spectra of standard stars, we have determined a temperature of 17,000 $\pm$ 500 K. The resultant Cepheid mass is 6.0 $\pm$ 0.4 M$_\odot$. This mass is consistent with main sequence evolutionary tracks with a moderate amount of convective overshoot. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0607489v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0607489v1-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 July, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2006. </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 to ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J.647:1387-1392,2006 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0606705">arXiv:astro-ph/0606705</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0606705">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0606705">ps</a>, <a href="https://arxiv.org/format/astro-ph/0606705">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/506966">10.1086/506966 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> FUSE observations of HD 5980: The wind structure of the eruptor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Koenigsberger%2C+G">Gloria Koenigsberger</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">Alexander W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D">Derck Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Auer%2C+L+H">Lawrence H. Auer</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="astro-ph/0606705v1-abstract-short" style="display: inline;"> HD 5980 is a unique system containing one massive star (star A) that is apparently entering the luminous blue variable phase, and an eclipsing companion (star B) that may have already evolved beyond this phase to become a Wolf-Rayet star. In this paper we present the results from FUSE observations obtained in 1999, 2000, and 2002 and one far-UV observation obtained by ORFEUS/BEFS in 1993 shortly… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606705v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0606705v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0606705v1-abstract-full" style="display: none;"> HD 5980 is a unique system containing one massive star (star A) that is apparently entering the luminous blue variable phase, and an eclipsing companion (star B) that may have already evolved beyond this phase to become a Wolf-Rayet star. In this paper we present the results from FUSE observations obtained in 1999, 2000, and 2002 and one far-UV observation obtained by ORFEUS/BEFS in 1993 shortly before the first eruption of HD 5980. The eight phase-resolved spectra obtained by FUSE in 2002 are analyzed in the context of a wind-eclipse model. This analysis shows that the wind of the eruptor obeyed a very fast velocity law in 2002, which is consistent with the line-driving mechanism. Large amplitude line-profile variations on the orbital period are shown to be due to the eclipse of star B by the wind of star A, although the eclipse due to gas flowing in the direction of star B is absent. This can only be explained if the wind of star A is not spherically symmetric, or if the eclipsed line radiation is "filled-in" by emission originating from somewhere else in the system, e.g., in the wind-wind collision region. Except for a slightly lower wind speed, the ORFEUS/BEFS spectrum is very similar to the spectrum obtained by FUSE at the same orbital phase: there is no indication of the impending eruption. However, the trend for decreasing wind velocity suggests the occurrence of the "bi-stability" mechanism, which in turn implies that the restructuring of the circumbinary environment caused by the transition from "fast, rarefied wind" to "slow, dense wind" was observed as the eruptive event. The underlying mechanism responsible for the long-term decrease in wind velocity that precipitated this change remains an open issue. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0606705v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0606705v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2006. </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, 13 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astron.J.132:1527-1538,2006 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0602173">arXiv:astro-ph/0602173</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0602173">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0602173">ps</a>, <a href="https://arxiv.org/format/astro-ph/0602173">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/503157">10.1086/503157 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Origin of Structures in Wolf-Rayet Winds: FUSE Observations of WR 135 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marchenko%2C+S+V">S. V. Marchenko</a>, <a href="/search/astro-ph?searchtype=author&query=Moffat%2C+A+F+J">A. F. J. Moffat</a>, <a href="/search/astro-ph?searchtype=author&query=St-Louis%2C+N">N. St-Louis</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</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="astro-ph/0602173v1-abstract-short" style="display: inline;"> We report the detection with FUSE of strong, highly blue-shifted absorption features appearing in the absorption troughs of practically all major P Cygni profiles in the presumably single Wolf-Rayet star WR135. These features also appear in the shock-sensitive OVI 1032/38 脜doublet, coincident both in time and velocity space with the rest of the lower-ionization species. Choosing between two alte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0602173v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0602173v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0602173v1-abstract-full" style="display: none;"> We report the detection with FUSE of strong, highly blue-shifted absorption features appearing in the absorption troughs of practically all major P Cygni profiles in the presumably single Wolf-Rayet star WR135. These features also appear in the shock-sensitive OVI 1032/38 脜doublet, coincident both in time and velocity space with the rest of the lower-ionization species. Choosing between two alternative interpretations: large-scale, coherent structures vs. localized, random shocks, we favor the latter. The absolute value of velocity, as well as velocity dispersion in the shocked region, the density of the shocked gas, and the time scales of the observed variability allow us to relate the observed shocks to the incidence of numerous over-dense clumps (blobs) in the wind of a hot, massive star. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0602173v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0602173v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 February, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2006. </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">12 pages, 2 figures; to be published in ApJL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J. 639 (2006) L75-L78 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0601623">arXiv:astro-ph/0601623</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0601623">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0601623">ps</a>, <a href="https://arxiv.org/format/astro-ph/0601623">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1051/0004-6361:20054380">10.1051/0004-6361:20054380 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The magnetic field and confined wind of the O star $胃^1$~Orionis~C </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Donati%2C+J+-">J. -F. Donati</a>, <a href="/search/astro-ph?searchtype=author&query=Landstreet%2C+J+D">J. D. Landstreet</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+P">P. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Strasser%2C+S">S. Strasser</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="astro-ph/0601623v1-abstract-short" style="display: inline;"> In this paper we confirm the presence of a globally-ordered, kG-strength magnetic field in the photosphere of the young O star $胃^1$~Orionis~C, and examine the properties of its optical line profile variations. A new series of high-resolution MuSiCoS Stokes $V$ and $I$ spectra has been acquired which samples approximately uniformly the rotational cycle of $胃^1$~Orionis~C. Using the Least-Squares… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0601623v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0601623v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0601623v1-abstract-full" style="display: none;"> In this paper we confirm the presence of a globally-ordered, kG-strength magnetic field in the photosphere of the young O star $胃^1$~Orionis~C, and examine the properties of its optical line profile variations. A new series of high-resolution MuSiCoS Stokes $V$ and $I$ spectra has been acquired which samples approximately uniformly the rotational cycle of $胃^1$~Orionis~C. Using the Least-Squares Deconvolution (LSD) multiline technique, we have succeeded in detecting variable Stokes $V$ Zeeman signatures associated with the LSD mean line profile. These signatures have been modeled to determine the magnetic field geometry. We have furthermore examined the profi le variations of lines formed in both the wind and photosphere using dynamic spectra. Based on spectrum synthesis fitting of the LSD profiles, we determine that the polar strength of the magnetic dipole component is $1150 \la B_{\rm d}\la 1800$~G and that the magnetic obliquity is $27\degr \la 尾\la 68\degr$, assuming $i=45\pm 20\degr$. The best-fit values for $i=45\degr$ are $B_{\rm d} = 1300 \pm 150 (1蟽)$~G and $尾= 50\degr \pm 6\degr (1蟽)$. Our data confirm the previous detection of a magnetic field in this star, and furthermore demonstrate the sinusoidal variability of the longitudinal field and accurately determine the phases and intensities of the magnetic extrema. The analysis of ``photospheric'' and ``wind'' line profile variations supports previous reports of the optical spectroscopic characteristics, and provides evidence for infall of material within the magnetic equatorial plane. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0601623v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0601623v1-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 January, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2006. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0510252">arXiv:astro-ph/0510252</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0510252">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0510252">ps</a>, <a href="https://arxiv.org/format/astro-ph/0510252">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</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/10.1086/498560">10.1086/498560 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Discordance of Mass-Loss Estimates for Galactic O-Type Stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fullerton%2C+A+W">A. W. Fullerton</a>, <a href="/search/astro-ph?searchtype=author&query=Massa%2C+D+L">D. L. Massa</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</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="astro-ph/0510252v1-abstract-short" style="display: inline;"> We have determined accurate values of the product of the mass-loss rate and the ion fraction of P^{4+}, Mdot q(P^{4+}), for a sample of 40 Galactic O-type stars by fitting stellar-wind profiles to observations of the P V resonance doublet obtained with FUSE, ORFEUS/BEFS, and Copernicus. When P^{4+} is the dominant ion in the wind, Mdot q(P^{4+}) approximates the mass-loss rate to within a factor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0510252v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0510252v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0510252v1-abstract-full" style="display: none;"> We have determined accurate values of the product of the mass-loss rate and the ion fraction of P^{4+}, Mdot q(P^{4+}), for a sample of 40 Galactic O-type stars by fitting stellar-wind profiles to observations of the P V resonance doublet obtained with FUSE, ORFEUS/BEFS, and Copernicus. When P^{4+} is the dominant ion in the wind, Mdot q(P^{4+}) approximates the mass-loss rate to within a factor of 2. Theory predicts that P^{4+} is the dominant ion in the winds of O7-O9.7 stars, though an empirical estimator suggests that the range from O4-O7 may be more appropriate. However, we find that the mass-loss rates obtained from P V wind profiles are systematically smaller than those obtained from fits to Halpha emission profiles or radio free-free emission by median factors of about 130 (if P^{4+} is dominant between O7 and O9.7) or about 20 (if P^{4+} is dominant between O4 and O7). These discordant measurements can be reconciled if the winds of O stars in the relevant temperature range are strongly clumped on small spatial scales. We use a simplified two-component model to investigate the volume filling factors of the denser regions. This clumping implies that mass-loss rates determined from "density squared" diagnostics have been systematically over-estimated by factors of 10 or more, at least for a subset of O stars. Reductions in the mass-loss rates of this size have important implications for the evolution of massive stars and quantitative estimates of the feedback that hot-star winds provide to their interstellar environments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0510252v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0510252v1-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 October, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2005. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 4 figures; accepted for publication in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophys.J.637:1025-1039,2006 </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Fullerton%2C+A&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <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 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