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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=Przybilla%2C+N&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Przybilla%2C+N&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Przybilla%2C+N&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Przybilla%2C+N&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </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/2502.06386">arXiv:2502.06386</a> <span> [<a href="https://arxiv.org/pdf/2502.06386">pdf</a>, <a href="https://arxiv.org/format/2502.06386">other</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"> The EDIBLES survey. X. The 6196 脜 diffuse interstellar band: Identification of side DIBs as indication for a small carrier molecule </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ebenbichler%2C+A">A. Ebenbichler</a>, <a href="/search/astro-ph?searchtype=author&query=On%C4%8D%C3%A1k%2C+M">M. On膷谩k</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Hrodmarsson%2C+H+R">H. R. Hrodmarsson</a>, <a href="/search/astro-ph?searchtype=author&query=Smoker%2C+J+V">J. V. Smoker</a>, <a href="/search/astro-ph?searchtype=author&query=Lallement%2C+R">R. Lallement</a>, <a href="/search/astro-ph?searchtype=author&query=Farhang%2C+A">A. Farhang</a>, <a href="/search/astro-ph?searchtype=author&query=Bhatt%2C+C">C. Bhatt</a>, <a href="/search/astro-ph?searchtype=author&query=Cami%2C+J">J. Cami</a>, <a href="/search/astro-ph?searchtype=author&query=Cordiner%2C+M">M. Cordiner</a>, <a href="/search/astro-ph?searchtype=author&query=Ehrenfreund%2C+P">P. Ehrenfreund</a>, <a href="/search/astro-ph?searchtype=author&query=Cox%2C+N+L+J">N. L. J. Cox</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=Foing%2C+B">B. Foing</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="2502.06386v1-abstract-short" style="display: inline;"> Context: Numerous studies of diffuse interstellar band (DIB) profiles have detected substructures, implying large molecules as their carriers. However, some of the narrowest DIBs generally do not show such substructure, suggesting the possibility of very small carriers. Aims: Based on the previously found tight correlation of the three narrow DIBs at 6196, 6440 and 6623 A and the present detection… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.06386v1-abstract-full').style.display = 'inline'; document.getElementById('2502.06386v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.06386v1-abstract-full" style="display: none;"> Context: Numerous studies of diffuse interstellar band (DIB) profiles have detected substructures, implying large molecules as their carriers. However, some of the narrowest DIBs generally do not show such substructure, suggesting the possibility of very small carriers. Aims: Based on the previously found tight correlation of the three narrow DIBs at 6196, 6440 and 6623 A and the present detection of weaker side DIBs to each of them in the extensive data set from the ESO Diffuse Interstellar Bands Large Exploration Survey, we investigate whether they may stem from small linear carrier molecules. This approach can lead to concrete DIB carrier suggestions, which can be tested in laboratory measurements in future studies. Methods: We suggest that the DIBs we study here represent individual rotational transitions of a small molecule. We determined the molecular constants from observation and compared them with data from a large set of quantum-chemical calculations to confine possible carrier candidates. Furthermore, we determined rotational temperatures by fitting line ratios using the fitted molecular models. Results: We determined molecular constants for three DIB systems and the corresponding transition types. The fitted rotational temperatures lie within the range of known interstellar diatomic molecules. We identified several DIB carrier candidates, almost all of them molecular ions. Some of them are metastable species, indicating the possibility of collision complexes as DIB carriers. Conclusions: If our hypothesis holds, this would be a major step toward the identification of a carrier molecule of the 6196 A DIB, the strongest among the narrow DIBs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.06386v1-abstract-full').style.display = 'none'; document.getElementById('2502.06386v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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, 12 figures, Accepted for publication in Astronomy & 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/2412.09720">arXiv:2412.09720</a> <span> [<a href="https://arxiv.org/pdf/2412.09720">pdf</a>, <a href="https://arxiv.org/format/2412.09720">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/10.1051/0004-6361/202347275">10.1051/0004-6361/202347275 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Newborn Be star systems observed shortly after mass transfer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rivinius%2C+T">Th. Rivinius</a>, <a href="/search/astro-ph?searchtype=author&query=Klement%2C+R">R. Klement</a>, <a href="/search/astro-ph?searchtype=author&query=Chojnowski%2C+S+D">S. D. Chojnowski</a>, <a href="/search/astro-ph?searchtype=author&query=Baade%2C+D">D. Baade</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=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Flo%2C+J+G">J. Guarro Flo</a>, <a href="/search/astro-ph?searchtype=author&query=Heathcote%2C+B">B. Heathcote</a>, <a href="/search/astro-ph?searchtype=author&query=Hadrava%2C+P">P. Hadrava</a>, <a href="/search/astro-ph?searchtype=author&query=Gies%2C+D">D. Gies</a>, <a href="/search/astro-ph?searchtype=author&query=Shepard%2C+K">K. Shepard</a>, <a href="/search/astro-ph?searchtype=author&query=Buil%2C+C">C. Buil</a>, <a href="/search/astro-ph?searchtype=author&query=Garde%2C+O">O. Garde</a>, <a href="/search/astro-ph?searchtype=author&query=Thizy%2C+O">O. Thizy</a>, <a href="/search/astro-ph?searchtype=author&query=Monnier%2C+J+D">J. D. Monnier</a>, <a href="/search/astro-ph?searchtype=author&query=Anugu%2C+N">N. Anugu</a>, <a href="/search/astro-ph?searchtype=author&query=Lanthermann%2C+C">C. Lanthermann</a>, <a href="/search/astro-ph?searchtype=author&query=Schaefer%2C+G">G. Schaefer</a>, <a href="/search/astro-ph?searchtype=author&query=Davies%2C+C">C. Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Kraus%2C+S">S. Kraus</a>, <a href="/search/astro-ph?searchtype=author&query=Ennis%2C+J">J. Ennis</a>, <a href="/search/astro-ph?searchtype=author&query=Setterholm%2C+B+R">B. R. Setterholm</a>, <a href="/search/astro-ph?searchtype=author&query=Gardner%2C+T">T. Gardner</a>, <a href="/search/astro-ph?searchtype=author&query=Ibrahim%2C+N">N. Ibrahim</a>, <a href="/search/astro-ph?searchtype=author&query=Chhabra%2C+S">S. Chhabra</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="2412.09720v2-abstract-short" style="display: inline;"> Many classical Be stars acquire their very rapid rotation by mass and angular-momentum transfer in massive binaries. Short-lived intermediate-phase objects have only been discovered recently. Data archives and the literature have been searched for additional candidates exhibiting this patterns. Thirteen candidates were identified at various confidence levels. Adding to the two known systems identi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09720v2-abstract-full').style.display = 'inline'; document.getElementById('2412.09720v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.09720v2-abstract-full" style="display: none;"> Many classical Be stars acquire their very rapid rotation by mass and angular-momentum transfer in massive binaries. Short-lived intermediate-phase objects have only been discovered recently. Data archives and the literature have been searched for additional candidates exhibiting this patterns. Thirteen candidates were identified at various confidence levels. Adding to the two known systems identified as classical Be star+pre-subdwarf binaries (LB-1 and HR6819), two more (V742Cas, HD44637) could be confirmed with interferometry, with V742Cas setting a new record for the smallest visually observed angular semi-major axis, at a=0.663mas. Two further ones (V447Sct, V1362Cyg) are not resolved interferometrically, but other evidence puts them at the same confidence level as LB-1. V2174Cyg is a candidate with very high confidence, but was not observed interferometrically. The remaining ones are either candidates with varying levels of confidence. Of a mostly magnitude complete sample of 328 Be stars, 0.5-1% are found to have recently completed the mass overflow that led to their formation. Another 5% are systems with compact subdwarf companions, i.e., further evolved after a previous overflow, and possibly two more percent harbor white dwarfs. All these systems are of early B-subtypes, however, and if the original sample is restricted to early subtypes (136 objects), these percentages increase by a factor of about 2.5, while dropping to zero for the mid and late subtypes (together 204 objects). This strongly suggests that early- vs. mid- and late-type Be stars have differently weighted channels to acquire their rapid rotation, namely binary interaction vs. evolutionary spin-up. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.09720v2-abstract-full').style.display = 'none'; document.getElementById('2412.09720v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication by A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 694, A172 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.23229">arXiv:2410.23229</a> <span> [<a href="https://arxiv.org/pdf/2410.23229">pdf</a>, <a href="https://arxiv.org/format/2410.23229">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/10.1051/0004-6361/202451878">10.1051/0004-6361/202451878 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantitative spectroscopy of multiple OB stars: I. The quadruple system HD 37061 at the centre of Messier 43 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aschenbrenner%2C+P">Patrick Aschenbrenner</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</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="2410.23229v2-abstract-short" style="display: inline;"> The majority of massive stars are located in binary or multiple star systems. Compared to single stars, these objects pose additional challenges to quantitative analyses based on model atmospheres. In particular, little information is currently available on the chemical composition of such systems. The members of the quadruple star system HD 37061, which excites the H II region Messier 43 in Orion… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23229v2-abstract-full').style.display = 'inline'; document.getElementById('2410.23229v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.23229v2-abstract-full" style="display: none;"> The majority of massive stars are located in binary or multiple star systems. Compared to single stars, these objects pose additional challenges to quantitative analyses based on model atmospheres. In particular, little information is currently available on the chemical composition of such systems. The members of the quadruple star system HD 37061, which excites the H II region Messier 43 in Orion, are fully characterised. Accurate and precise abundances for all elements with lines traceable in the optical spectrum are derived for the first time. A hybrid non-local thermodynamic equilibrium (non-LTE) approach, using line-blanketed hydrostatic model atmospheres computed with the ATLAS12 code in combination with non-LTE line-formation calculations with DETAIL and SURFACE, was employed. A high-resolution composite spectrum was analysed for the atmospheric parameters and elemental abundances of the individual stars. Fundamental stellar parameters were derived based on stellar evolution tracks, and the interstellar reddening was characterised. We determined the fundamental parameters and chemical abundances for three stars in the HD 37061 system. The fourth and faintest star in the system shows no distinct spectral features, as a result of its fast rotation. However, this star has noticeable effects on the continuum. The derived element abundances and determined ages of the individual stars are consistent with each other, and the abundances coincide with the cosmic abundance standard. We find an excellent agreement between our spectroscopic distance and the Gaia Data Release 3 parallax distance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23229v2-abstract-full').style.display = 'none'; document.getElementById('2410.23229v2-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> 4 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 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">10 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 691, A361 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.16396">arXiv:2408.16396</a> <span> [<a href="https://arxiv.org/pdf/2408.16396">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/10.1117/12.3017752">10.1117/12.3017752 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The MICADO first light imager for the ELT: overview and current Status </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sturm%2C+E">E. Sturm</a>, <a href="/search/astro-ph?searchtype=author&query=Davies%2C+R">R. Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Alves%2C+J">J. Alves</a>, <a href="/search/astro-ph?searchtype=author&query=Cl%C3%A9net%2C+Y">Y. Cl茅net</a>, <a href="/search/astro-ph?searchtype=author&query=Kotilainen%2C+J">J. Kotilainen</a>, <a href="/search/astro-ph?searchtype=author&query=Monna%2C+A">A. Monna</a>, <a href="/search/astro-ph?searchtype=author&query=Nicklas%2C+H">H. Nicklas</a>, <a href="/search/astro-ph?searchtype=author&query=Pott%2C+J+-">J. -U. Pott</a>, <a href="/search/astro-ph?searchtype=author&query=Tolstoy%2C+E">E. Tolstoy</a>, <a href="/search/astro-ph?searchtype=author&query=Vulcani%2C+B">B. Vulcani</a>, <a href="/search/astro-ph?searchtype=author&query=Achren%2C+J">J. Achren</a>, <a href="/search/astro-ph?searchtype=author&query=Annadevara%2C+S">S. Annadevara</a>, <a href="/search/astro-ph?searchtype=author&query=Anwand-Heerwart%2C+H">H. Anwand-Heerwart</a>, <a href="/search/astro-ph?searchtype=author&query=Arcidiacono%2C+C">C. Arcidiacono</a>, <a href="/search/astro-ph?searchtype=author&query=Barboza%2C+S">S. Barboza</a>, <a href="/search/astro-ph?searchtype=author&query=Barl%2C+L">L. Barl</a>, <a href="/search/astro-ph?searchtype=author&query=Baudoz%2C+P">P. Baudoz</a>, <a href="/search/astro-ph?searchtype=author&query=Bender%2C+R">R. Bender</a>, <a href="/search/astro-ph?searchtype=author&query=Bezawada%2C+N">N. Bezawada</a>, <a href="/search/astro-ph?searchtype=author&query=Biondi%2C+F">F. Biondi</a>, <a href="/search/astro-ph?searchtype=author&query=Bizenberger%2C+P">P. Bizenberger</a>, <a href="/search/astro-ph?searchtype=author&query=Blin%2C+A">A. Blin</a>, <a href="/search/astro-ph?searchtype=author&query=Bon%C3%A9%2C+A">A. Bon茅</a>, <a href="/search/astro-ph?searchtype=author&query=Bonifacio%2C+P">P. Bonifacio</a>, <a href="/search/astro-ph?searchtype=author&query=Borgo%2C+B">B. Borgo</a> , et al. (129 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="2408.16396v1-abstract-short" style="display: inline;"> MICADO is a first light instrument for the Extremely Large Telescope (ELT), set to start operating later this decade. It will provide diffraction limited imaging, astrometry, high contrast imaging, and long slit spectroscopy at near-infrared wavelengths. During the initial phase operations, adaptive optics (AO) correction will be provided by its own natural guide star wavefront sensor. In its fina… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16396v1-abstract-full').style.display = 'inline'; document.getElementById('2408.16396v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16396v1-abstract-full" style="display: none;"> MICADO is a first light instrument for the Extremely Large Telescope (ELT), set to start operating later this decade. It will provide diffraction limited imaging, astrometry, high contrast imaging, and long slit spectroscopy at near-infrared wavelengths. During the initial phase operations, adaptive optics (AO) correction will be provided by its own natural guide star wavefront sensor. In its final configuration, that AO system will be retained and complemented by the laser guide star multi-conjugate adaptive optics module MORFEO (formerly known as MAORY). Among many other things, MICADO will study exoplanets, distant galaxies and stars, and investigate black holes, such as Sagittarius A* at the centre of the Milky Way. After their final design phase, most components of MICADO have moved on to the manufacturing and assembly phase. Here we summarize the final design of the instrument and provide an overview about its current manufacturing status and the timeline. Some lessons learned from the final design review process will be presented in order to help future instrumentation projects to cope with the challenges arising from the substantial differences between projects for 8-10m class telescopes (e.g. ESO-VLT) and the next generation Extremely Large Telescopes (e.g. ESO-ELT). Finally, the expected performance will be discussed in the context of the current landscape of astronomical observatories and instruments. For instance, MICADO will have similar sensitivity as the James Webb Space Telescope (JWST), but with six times the spatial resolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16396v1-abstract-full').style.display = 'none'; document.getElementById('2408.16396v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings of the SPIE, Volume 13096, id. 1309611 11 pp. (2024)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.01037">arXiv:2407.01037</a> <span> [<a href="https://arxiv.org/pdf/2407.01037">pdf</a>, <a href="https://arxiv.org/format/2407.01037">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> <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/10.1051/0004-6361/202347732">10.1051/0004-6361/202347732 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Runaway BN supergiant star HD 93840: Progenitor of an imminent core-collapse supernova above the Galactic plane </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=We%C3%9Fmayer%2C+D">D. We脽mayer</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.01037v1-abstract-short" style="display: inline;"> We present a quantitative spectral analysis of the extreme nitrogen-enhanced supergiant HD 93840 (BN1 Ib) at an intermediate galactic latitude. Based on an optical high-resolution spectrum and complementary ultraviolet and infrared (spectro-)photometry, in addition to Gaia data, we carried out a full characterisation of the star's properties. We used both hydrostatic and unified (photosphere+wind)… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01037v1-abstract-full').style.display = 'inline'; document.getElementById('2407.01037v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.01037v1-abstract-full" style="display: none;"> We present a quantitative spectral analysis of the extreme nitrogen-enhanced supergiant HD 93840 (BN1 Ib) at an intermediate galactic latitude. Based on an optical high-resolution spectrum and complementary ultraviolet and infrared (spectro-)photometry, in addition to Gaia data, we carried out a full characterisation of the star's properties. We used both hydrostatic and unified (photosphere+wind) model atmospheres that account for deviations from local thermodynamic equilibrium. A highly unusual surface CNO-mixing signature and a marked stellar overluminosity compared to the mass imply a binary channel for the star's past evolution. The kinematics shows that it has reached its current position above the Galactic plane as a runaway star, likely ejected by the supernova explosion of its former companion star. Its current bulk composition, with a notably increased mean molecular weight due to core He- and progressed shell H-burning, suggests an advanced evolutionary stage. It is poised to yield a rare core-collapse supernova of a blue supergiant about ten OB star population scale heights above the Galactic disk relatively soon, contributing to the metal enrichment of the circumgalactic medium. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01037v1-abstract-full').style.display = 'none'; document.getElementById('2407.01037v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 14 figures, published in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A, 687, L7 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.00547">arXiv:2403.00547</a> <span> [<a href="https://arxiv.org/pdf/2403.00547">pdf</a>, <a href="https://arxiv.org/format/2403.00547">other</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"> The EDIBLES Survey. VIII. Band profile alignment of diffuse interstellar bands </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ebenbichler%2C+A">A. Ebenbichler</a>, <a href="/search/astro-ph?searchtype=author&query=Smoker%2C+J+V">J. V. Smoker</a>, <a href="/search/astro-ph?searchtype=author&query=Lallement%2C+R">R. Lallement</a>, <a href="/search/astro-ph?searchtype=author&query=Farhang%2C+A">A. Farhang</a>, <a href="/search/astro-ph?searchtype=author&query=Cox%2C+N+L+J">N. L. J. Cox</a>, <a href="/search/astro-ph?searchtype=author&query=Joblin%2C+C">C. Joblin</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=Linnartz%2C+H">H. Linnartz</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Ehrenfreund%2C+P">P. Ehrenfreund</a>, <a href="/search/astro-ph?searchtype=author&query=Cami%2C+J">J. Cami</a>, <a href="/search/astro-ph?searchtype=author&query=Cordiner%2C+M">M. Cordiner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.00547v1-abstract-short" style="display: inline;"> Context: There have been many attempts to identify families of diffuse interstellar bands (DIBs) with perfectly correlating band strengths. Although major efforts have been made to classify broadly based DIB families and important insights have been gained, no family has been identified with sufficient accuracy or statistical significance to prove that a series of selected DIBs originates from the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00547v1-abstract-full').style.display = 'inline'; document.getElementById('2403.00547v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.00547v1-abstract-full" style="display: none;"> Context: There have been many attempts to identify families of diffuse interstellar bands (DIBs) with perfectly correlating band strengths. Although major efforts have been made to classify broadly based DIB families and important insights have been gained, no family has been identified with sufficient accuracy or statistical significance to prove that a series of selected DIBs originates from the same carrier. This can be attributed in part to the exclusive use of equivalent widths to establish DIB families. Aims: In a change of strategy, we search for DIBs that are highly correlated in both band strength and profile shape. This approach increases the chance of correlating DIBs being members of one family and originating from the same carrier molecule. We also search for correlations between DIB profile families and atomic interstellar lines, with the goal of further chemically constraining possible DIB carriers. Methods: We adapted the well-known method of time-series alignment to perform a spectral alignment; that is, DIB alignment. In a second step, we analysed the alignment results using a clustering analysis. This method required a statistically significant data set of DIB sight lines. The ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES) data were perfectly suited for this application. Results: We report eight DIB families with correlating strengths and profiles, as well as four previously unreported DIBs in the visual range, found using DIB alignment. All profile family members show Pearson correlation coefficients in band strength higher than 0.9. In particular, we report the 6614 - 6521 AA DIB pair, in which both DIBs show the same triple-peak substructure and an unprecedented band strength Pearson correlation coefficient of 0.9935. The presented approach opens up new perspectives that can guide the laboratory search for DIB carriers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00547v1-abstract-full').style.display = 'none'; document.getElementById('2403.00547v1-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">53 pages, 53 figures, Accepted for publication in Astronomy & 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/2308.06164">arXiv:2308.06164</a> <span> [<a href="https://arxiv.org/pdf/2308.06164">pdf</a>, <a href="https://arxiv.org/format/2308.06164">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/10.1051/0004-6361/202347253">10.1051/0004-6361/202347253 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The blue supergiant Sher 25 revisited in the Gaia era </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=We%C3%9Fmayer%2C+D">D. We脽mayer</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Ebenbichler%2C+A">A. Ebenbichler</a>, <a href="/search/astro-ph?searchtype=author&query=Aschenbrenner%2C+P">P. Aschenbrenner</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</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="2308.06164v1-abstract-short" style="display: inline;"> Aims. The evolutionary status of the blue supergiant Sher 25 and its membership to the massive cluster NGC 3603 are investigated. Methods. A hybrid non-LTE (local thermodynamic equilibrium) spectrum synthesis approach is employed to analyse a high-resolution optical spectrum of Sher 25 and five similar early B-type comparison stars in order to derive atmospheric parameters and elemental abundances… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.06164v1-abstract-full').style.display = 'inline'; document.getElementById('2308.06164v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.06164v1-abstract-full" style="display: none;"> Aims. The evolutionary status of the blue supergiant Sher 25 and its membership to the massive cluster NGC 3603 are investigated. Methods. A hybrid non-LTE (local thermodynamic equilibrium) spectrum synthesis approach is employed to analyse a high-resolution optical spectrum of Sher 25 and five similar early B-type comparison stars in order to derive atmospheric parameters and elemental abundances. Fundamental stellar parameters are determined by considering stellar evolution tracks, Gaia Data Release 3 (DR3) data and complementary distance information. Interstellar reddening and the reddening law along the sight line towards Sher 25 are constrained employing UV photometry for the first time in addition to optical and infrared data. The distance to NGC 3603 is reevaluated based on Gaia DR3 data of the innermost cluster O-stars. Results. The spectroscopic distance derived from the quantitative analysis implies that Sher 25 lies in the foreground of NGC 3603, which is found to have a distance of $d_\mathrm{NGC 3603}$ = 6250$\pm$150 pc. A cluster membership is also excluded as the hourglass nebula is unaffected by the vigorous stellar winds of the cluster stars and from the different excitation signatures of the hourglass nebula and the nebula around NGC 3603. Sher 25 turns out to have a luminosity of log L/L$_\odot$ = 5.48$\pm$0.14, equivalent to that of a $\sim$27 $M_\odot$ supergiant in a single-star scenario, which is about half of the mass assumed so far, bringing it much closer in its characteristics to Sk-69掳202, the progenitor of SN 1987A. Sher 25 is significantly older than NGC 3603. Further arguments for a binary (merger) evolutionary scenario of Sher 25 are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.06164v1-abstract-full').style.display = 'none'; document.getElementById('2308.06164v1-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">27 pages, 22 figures, Accepted for publication in Astronomy & Astrophysics, Data: https://doi.org/10.5281/zenodo.8230158</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 677, A175 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.14375">arXiv:2302.14375</a> <span> [<a href="https://arxiv.org/pdf/2302.14375">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/10.18727/0722-6691/5286">10.18727/0722-6691/5286 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ESO's Extremely Large Telescope Working Groups </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Padovani%2C+P">Paolo Padovani</a>, <a href="/search/astro-ph?searchtype=author&query=Cirasuolo%2C+M">Michele Cirasuolo</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Burg%2C+R">Remco van der Burg</a>, <a href="/search/astro-ph?searchtype=author&query=Cantalloube%2C+F">Faustine Cantalloube</a>, <a href="/search/astro-ph?searchtype=author&query=George%2C+E">Elizabeth George</a>, <a href="/search/astro-ph?searchtype=author&query=Kasper%2C+M">Markus Kasper</a>, <a href="/search/astro-ph?searchtype=author&query=Leschinski%2C+K">Kieran Leschinski</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+C">Carlos Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Milli%2C+J">Julien Milli</a>, <a href="/search/astro-ph?searchtype=author&query=M%C3%B6hler%2C+S">Sabine M枚hler</a>, <a href="/search/astro-ph?searchtype=author&query=Neeser%2C+M">Mark Neeser</a>, <a href="/search/astro-ph?searchtype=author&query=Neichel%2C+B">Benoit Neichel</a>, <a href="/search/astro-ph?searchtype=author&query=Otarola%2C+A">Angel Otarola</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez-Janssen%2C+R">Rub茅n S谩nchez-Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Serra%2C+B">Benoit Serra</a>, <a href="/search/astro-ph?searchtype=author&query=Smette%2C+A">Alain Smette</a>, <a href="/search/astro-ph?searchtype=author&query=Valenti%2C+E">Elena Valenti</a>, <a href="/search/astro-ph?searchtype=author&query=Verinaud%2C+C">Christophe Verinaud</a>, <a href="/search/astro-ph?searchtype=author&query=Vernet%2C+J">Jo毛l Vernet</a>, <a href="/search/astro-ph?searchtype=author&query=Absil%2C+O">Olivier Absil</a>, <a href="/search/astro-ph?searchtype=author&query=Agapito%2C+G">Guido Agapito</a>, <a href="/search/astro-ph?searchtype=author&query=Andersen%2C+M">Morten Andersen</a>, <a href="/search/astro-ph?searchtype=author&query=Arcidiacono%2C+C">Carmelo Arcidiacono</a>, <a href="/search/astro-ph?searchtype=author&query=Arko%2C+M">Matej Arko</a>, <a href="/search/astro-ph?searchtype=author&query=Baudoz%2C+P">Pierre Baudoz</a> , et al. (60 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="2302.14375v1-abstract-short" style="display: inline;"> Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO's Extremely Large Telescope, or ELT for short, is a revolutionary ground-based telescope that will have a 39-metre main mirror and will be the largest visible and infrared light telescope in the world. To address specific topics that are needed for the science operations an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.14375v1-abstract-full').style.display = 'inline'; document.getElementById('2302.14375v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.14375v1-abstract-full" style="display: none;"> Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO's Extremely Large Telescope, or ELT for short, is a revolutionary ground-based telescope that will have a 39-metre main mirror and will be the largest visible and infrared light telescope in the world. To address specific topics that are needed for the science operations and calibrations of the telescope, thirteen specific working groups were created to coordinate the effort between ESO, the instrument consortia, and the wider community. We describe here the goals of these working groups as well as their achievements so far. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.14375v1-abstract-full').style.display = 'none'; document.getElementById('2302.14375v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Messenger, vol. 189, (December 2022) p. 23-30 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.09462">arXiv:2301.09462</a> <span> [<a href="https://arxiv.org/pdf/2301.09462">pdf</a>, <a href="https://arxiv.org/format/2301.09462">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/10.1051/0004-6361/202244906">10.1051/0004-6361/202244906 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Aschenbrenner%2C+P">Patrick Aschenbrenner</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">Keith Butler</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="2301.09462v1-abstract-short" style="display: inline;"> Context. Late O-type stars at luminosities $\log L/L_\odot \lesssim 5.2$ show weak winds with mass-loss rates lower than 10$^{-8} M_\odot$ yr$^{-1}$. This implies that their photospheric layers are not strongly affected by the stellar wind. Aims. A hybrid non-local thermodynamic equilibrium (non-LTE) approach is tested for analyses of late O-type stars. A sample of 20 mostly sharp-lined Galactic O… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.09462v1-abstract-full').style.display = 'inline'; document.getElementById('2301.09462v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.09462v1-abstract-full" style="display: none;"> Context. Late O-type stars at luminosities $\log L/L_\odot \lesssim 5.2$ show weak winds with mass-loss rates lower than 10$^{-8} M_\odot$ yr$^{-1}$. This implies that their photospheric layers are not strongly affected by the stellar wind. Aims. A hybrid non-local thermodynamic equilibrium (non-LTE) approach is tested for analyses of late O-type stars. A sample of 20 mostly sharp-lined Galactic O stars of spectral types O8 to O9.7 and luminosity classes V and IV, previously studied in the literature using full non-LTE model atmospheres, is investigated. Methods. Hydrostatic plane-parallel atmospheric structures and synthetic spectra computed with Kurucz's Atlas12 code together with non-LTE line-formation codes Detail and Surface, which account for the effects of turbulent pressure on the atmosphere, were employed. High-resolution spectra were analysed to derive atmospheric parameters and elemental abundances. Fundamental stellar parameters were derived by considering stellar evolution tracks and Gaia EDR3 parallaxes. Interstellar reddening was characterised by fitting spectral energy distributions from the UV to the mid-IR. Results. A high precision and accuracy is achieved for all derived parameters for 16 sample stars. Turbulent pressure effects turn out have significant effects. Effective temperatures are determined to 1-3% uncertainty levels, surface gravities to 0.05 to 0.10 dex, masses to better than 8%, radii to better than 10%, and luminosities to better than 20% uncertainty typically. Abundances for C, N, O, Ne, Mg, Al, Si are derived with uncertainties of 0.05 to 0.10 dex and for helium within 0.03 to 0.05 dex (1$蟽$ standard deviations) in general. Distances to the Lac OB1b association and to the open clusters NGC 2244, IC 1805, NGC 457, and IC 1396 are determined as a byproduct. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.09462v1-abstract-full').style.display = 'none'; document.getElementById('2301.09462v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">31 pages, 23 figures, Accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 671, A36 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.00358">arXiv:2211.00358</a> <span> [<a href="https://arxiv.org/pdf/2211.00358">pdf</a>, <a href="https://arxiv.org/format/2211.00358">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/10.1038/s41550-022-01809-6">10.1038/s41550-022-01809-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> $纬$ Columbae: the recently stripped, pulsating core of a massive star </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Irrgang%2C+A">Andreas Irrgang</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Meynet%2C+G">Georges Meynet</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="2211.00358v1-abstract-short" style="display: inline;"> A vital condition for life on Earth is the steady supply of radiative heat by the Sun. Like all other stars, the Sun generates its emitted energy in its central regions where densities and temperatures are high enough for nuclear fusion processes to take place. Because stellar cores are usually covered by an opaque envelope, most of our knowledge about them and their life-giving nuclear processes… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.00358v1-abstract-full').style.display = 'inline'; document.getElementById('2211.00358v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.00358v1-abstract-full" style="display: none;"> A vital condition for life on Earth is the steady supply of radiative heat by the Sun. Like all other stars, the Sun generates its emitted energy in its central regions where densities and temperatures are high enough for nuclear fusion processes to take place. Because stellar cores are usually covered by an opaque envelope, most of our knowledge about them and their life-giving nuclear processes comes from theoretical modelling or from indirect observations such as the detection of solar neutrinos and the study of stellar pulsations, respectively. Only in very rare cases, stars may expose their cores, e.g., when a tiny fraction of them evolves into Wolf-Rayet or helium hot subdwarf stars. However, for the vast majority of stars, namely unevolved stars that burn hydrogen to helium in their centres, direct observational clues on the cores are still missing. Based on a comprehensive spectroscopic and asteroseismic analysis, we show here that the bright B-type star $纬$ Columbae is the stripped pulsating core (with a mass of $4$-$5\,M_\odot$, where $M_\odot$ is the mass of the Sun) of a previously much more massive star of roughly $12\,M_\odot$ that just finished central hydrogen fusion. The star's inferred parameters indicate that it is still in a short-lived post-stripping structural readjustment phase, making it an extremely rare object. The discovery of this unique star paves the way to obtain invaluable insights into the physics of both single and binary stars with respect to nuclear astrophysics and common-envelope evolution. In particular, it provides first observational constraints on the structure and evolution of stripped envelope stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.00358v1-abstract-full').style.display = 'none'; document.getElementById('2211.00358v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">This preprint has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in Nature Astronomy, and is available online at https://doi.org/10.1038/s41550-022-01809-6</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Astron (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.14314">arXiv:2209.14314</a> <span> [<a href="https://arxiv.org/pdf/2209.14314">pdf</a>, <a href="https://arxiv.org/format/2209.14314">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/10.1017/S1743921322002186">10.1017/S1743921322002186 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MUSE 3D spectroscopy of BA-type supergiants in NGC 300 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez-Tor%C3%A0%2C+G">Gemma Gonz谩lez-Tor脿</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">Miguel A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Dreizler%2C+S">Stefan Dreizler</a>, <a href="/search/astro-ph?searchtype=author&query=Roth%2C+M+M">Martin M. Roth</a>, <a href="/search/astro-ph?searchtype=author&query=Kamann%2C+S">Sebastian Kamann</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">Norberto Castro</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="2209.14314v1-abstract-short" style="display: inline;"> We present the results obtained using spectroscopic data taken with the intermediateresolution Multi Unit Spectroscopic Explorer (MUSE) of B and A-type supergiants and bright giants in the Sculptor Group galaxy NGC 300. For our analysis, a hybrid local thermodynamic equilibrium (LTE) line-blanketing+non-LTE method was used to improve the previously published results for the same data. In addition,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.14314v1-abstract-full').style.display = 'inline'; document.getElementById('2209.14314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.14314v1-abstract-full" style="display: none;"> We present the results obtained using spectroscopic data taken with the intermediateresolution Multi Unit Spectroscopic Explorer (MUSE) of B and A-type supergiants and bright giants in the Sculptor Group galaxy NGC 300. For our analysis, a hybrid local thermodynamic equilibrium (LTE) line-blanketing+non-LTE method was used to improve the previously published results for the same data. In addition, we present some further applications of this work, which includes extending the flux-weighted gravity luminosity relationship (FGLR), a distance determination method for supergiants. This pioneering work opens up a new window to explore this relation, and also demonstrates the enormous potential of integral field spectroscopy (IFS) for extragalactic quantitative stellar studies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.14314v1-abstract-full').style.display = 'none'; document.getElementById('2209.14314v1-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 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">6 pages, 4 figures, accepted for publication at the Proceedings of the IAUS361: Massive Stars Near and Far</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Proc. IAU 18 (2022) 151-156 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.02692">arXiv:2208.02692</a> <span> [<a href="https://arxiv.org/pdf/2208.02692">pdf</a>, <a href="https://arxiv.org/format/2208.02692">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/10.1051/0004-6361/202243973">10.1051/0004-6361/202243973 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantitative spectroscopy of B-type supergiants </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=We%C3%9Fmayer%2C+D">D. We脽mayer</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</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="2208.02692v2-abstract-short" style="display: inline;"> Context. B-type supergiants are versatile tools to address various astrophysical topics, ranging from stellar atmospheres over stellar and galactic evolution to the cosmic distance scale. Aims. A hybrid non-LTE approach - line-blanketed model atmospheres computed under the assumption of local thermodynamic equilibrium (LTE) in combination with line formation calculations that account for deviation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.02692v2-abstract-full').style.display = 'inline'; document.getElementById('2208.02692v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.02692v2-abstract-full" style="display: none;"> Context. B-type supergiants are versatile tools to address various astrophysical topics, ranging from stellar atmospheres over stellar and galactic evolution to the cosmic distance scale. Aims. A hybrid non-LTE approach - line-blanketed model atmospheres computed under the assumption of local thermodynamic equilibrium (LTE) in combination with line formation calculations that account for deviations from LTE - is tested for quantitative analyses of B-type supergiants with masses $M<30 M_{\odot}$, characterising a sample of 14 Galactic objects. Methods. Hydrostatic plane-parallel atmospheric structures and synthetic spectra computed with Kurucz's Atlas12 code together with the non-LTE line-formation codes Detail/Surface are compared to results from full non-LTE calculations with Tlusty, and the effects of turbulent pressure on the models are investigated. High-resolution spectra are analysed for atmospheric parameters, using Stark-broadened hydrogen lines and multiple metal ionisation equilibria, and for elemental abundances. Fundamental stellar parameters are derived by considering stellar evolution tracks and Gaia EDR3 parallaxes. Interstellar reddening towards the target stars is determined by matching model spectral energy distributions to observed ones. Results. Our hybrid non-LTE approach turns out to be equivalent to hydrostatic full non-LTE modelling for the deeper photospheric layers of the B-type supergiants considered. Turbulent pressure can become relevant for microturbulent velocities larger than 10 km s$^{-1}$. High precision and accuracy is achieved for all derived parameters by bringing multiple indicators to agreement simultaneously. Abundances for chemical species (He, C, N, O, Ne, Mg, Al, Si, S, Ar, Fe) are derived with uncertainties of 0.05 to 0.10 dex. The derived ratios N/C vs. N/O tightly follow the predictions from Geneva stellar evolution models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.02692v2-abstract-full').style.display = 'none'; document.getElementById('2208.02692v2-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 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages, 24 figures, Accepted for publication in Astronomy & Astrophysics, Data: https://doi.org/10.5281/zenodo.6802567</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 668, A92 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.12792">arXiv:2207.12792</a> <span> [<a href="https://arxiv.org/pdf/2207.12792">pdf</a>, <a href="https://arxiv.org/format/2207.12792">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/10.1051/0004-6361/202244112">10.1051/0004-6361/202244112 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Gaia-ESO survey: A spectroscopic study of the young open cluster NGC 3293 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Blaz%C3%A8re%2C+A">A. Blaz猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Semaan%2C+T">T. Semaan</a>, <a href="/search/astro-ph?searchtype=author&query=Gosset%2C+E">E. Gosset</a>, <a href="/search/astro-ph?searchtype=author&query=Zorec%2C+J">J. Zorec</a>, <a href="/search/astro-ph?searchtype=author&query=Fr%C3%A9mat%2C+Y">Y. Fr茅mat</a>, <a href="/search/astro-ph?searchtype=author&query=Blomme%2C+R">R. Blomme</a>, <a href="/search/astro-ph?searchtype=author&query=Daflon%2C+S">S. Daflon</a>, <a href="/search/astro-ph?searchtype=author&query=Lobel%2C+A">A. Lobel</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+F">M. F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Gebran%2C+M">M. Gebran</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Santos%2C+W">W. Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Tautvai%C5%A1ien%C4%97%2C+G">G. Tautvai拧ien臈</a>, <a href="/search/astro-ph?searchtype=author&query=Gilmore%2C+G">G. Gilmore</a>, <a href="/search/astro-ph?searchtype=author&query=Randich%2C+S">S. Randich</a>, <a href="/search/astro-ph?searchtype=author&query=Alfaro%2C+E+J">E. J. Alfaro</a>, <a href="/search/astro-ph?searchtype=author&query=Bergemann%2C+M">M. Bergemann</a>, <a href="/search/astro-ph?searchtype=author&query=Carraro%2C+G">G. Carraro</a>, <a href="/search/astro-ph?searchtype=author&query=Damiani%2C+F">F. Damiani</a>, <a href="/search/astro-ph?searchtype=author&query=Franciosini%2C+E">E. Franciosini</a>, <a href="/search/astro-ph?searchtype=author&query=Morbidelli%2C+L">L. Morbidelli</a>, <a href="/search/astro-ph?searchtype=author&query=Pancino%2C+E">E. Pancino</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="2207.12792v1-abstract-short" style="display: inline;"> We present a spectroscopic analysis of the GIRAFFE and UVES data collected by the Gaia-ESO survey for the young open cluster NGC 3293. Archive spectra from the same instruments obtained in the framework of the `VLT-FLAMES survey of massive stars' are also analysed. Atmospheric parameters, non-LTE chemical abundances for six elements, or variability information are reported for a total of about 160… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.12792v1-abstract-full').style.display = 'inline'; document.getElementById('2207.12792v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.12792v1-abstract-full" style="display: none;"> We present a spectroscopic analysis of the GIRAFFE and UVES data collected by the Gaia-ESO survey for the young open cluster NGC 3293. Archive spectra from the same instruments obtained in the framework of the `VLT-FLAMES survey of massive stars' are also analysed. Atmospheric parameters, non-LTE chemical abundances for six elements, or variability information are reported for a total of about 160 B stars spanning a wide range in terms of spectral types (B1 to B9.5) and rotation rate (up to 350 km/s). We take advantage of the multi-epoch observations to detect several binary systems or intrinsically line-profile variables. A deconvolution algorithm is used to infer the current, true (deprojected) rotational velocity distribution. We find a broad, Gaussian-like distribution peaking around 200-250 km/s. Although some stars populate the high-velocity tail, most stars in the cluster appear to rotate far from critical. We discuss the chemical properties of the cluster, including the low occurrence of abundance peculiarities in the late B stars and the paucity of objects showing CN-cycle burning products at their surface. We argue that the former result can largely be explained by the inhibition of diffusion effects because of fast rotation, while the latter is generally in accord with the predictions of single-star evolutionary models under the assumption of a wide range of initial spin rates at the onset of main-sequence evolution. However, we find some evidence for a less efficient mixing in two quite rapidly rotating stars that are among the most massive objects in our sample. Finally, we obtain a cluster age of ~20 Myrs through a detailed, star-to-star correction of our results for the effect of stellar rotation. This is significantly older than previous estimates from turn-off fitting that fully relied on classical, non-rotating isochrones. [abridged] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.12792v1-abstract-full').style.display = 'none'; document.getElementById('2207.12792v1-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 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">29 pages, 24 figures, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 665, A108 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.12562">arXiv:2203.12562</a> <span> [<a href="https://arxiv.org/pdf/2203.12562">pdf</a>, <a href="https://arxiv.org/format/2203.12562">other</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> <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/10.1051/0004-6361/202142990">10.1051/0004-6361/202142990 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CRIRES high-resolution near-infrared spectroscopy of diffuse interstellar band profiles. Detection of 12 new DIBs in the YJ band and the introduction of a combined ISM sight line and stellar analysis approach </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ebenbichler%2C+A">A. Ebenbichler</a>, <a href="/search/astro-ph?searchtype=author&query=Postel%2C+A">A. Postel</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Seifahrt%2C+A">A. Seifahrt</a>, <a href="/search/astro-ph?searchtype=author&query=We%C3%9Fmayer%2C+D">D. We脽mayer</a>, <a href="/search/astro-ph?searchtype=author&query=Kausch%2C+W">W. Kausch</a>, <a href="/search/astro-ph?searchtype=author&query=Firnstein%2C+M">M. Firnstein</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=Kaufer%2C+A">A. Kaufer</a>, <a href="/search/astro-ph?searchtype=author&query=Linnartz%2C+H">H. Linnartz</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="2203.12562v3-abstract-short" style="display: inline;"> A high spectral resolution investigation of diffuse interstellar bands (DIBs) in the near-infrared ($YJ$ band) is conducted to test new methods, to confirm and improve existing parameters, and to search for new DIBs. Methods: The CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the European Southern Observatory's Very Large Telescope was employed to obtain spectra of four redd… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.12562v3-abstract-full').style.display = 'inline'; document.getElementById('2203.12562v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.12562v3-abstract-full" style="display: none;"> A high spectral resolution investigation of diffuse interstellar bands (DIBs) in the near-infrared ($YJ$ band) is conducted to test new methods, to confirm and improve existing parameters, and to search for new DIBs. Methods: The CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the European Southern Observatory's Very Large Telescope was employed to obtain spectra of four reddened background supergiant stars (HD 183143, HD 165784, HD 92207, HD 111613) and an unreddened comparison star (HD 87737) at the highest resolution of $R \approx 100000$ currently achievable at near-infrared wavelengths. The correction for telluric absorption was performed by a modelling approach. Non-local thermodynamic equilibrium spectral modelling of available optical and the new near-infrared spectra facilitated a comprehensive characterisation of the atmospheric properties of the background stars. A more precise and accurate determination of the reddening law along the sight lines could be achieved than feasible before by comparison of the observed and model spectral energy distributions. For DIBs that overlap with stellar lines the DIB profile shapes could be recovered. Results: Seventeen known near-infrared DIBs were confirmed, and 12 previously unknown and generally weaker DIBs were identified in the $YJ$ band. Three DIBs that show uniform profiles along all sight lines were identified, possibly connected to transitions from a common lower state of the same carrier. The divergent extinction curve towards the frequently discussed DIB standard star HD 183143 could be reproduced for the first time, requiring extra absorption by $\sim$3.5 mag due to polycyclic aromatic hydrocarbons (PAHs) to match the ultraviolet extinction bump. This extra absorption probably stems from a circumstellar bubble lying in front of the star which is intersected tangentially by the line of sight. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.12562v3-abstract-full').style.display = 'none'; document.getElementById('2203.12562v3-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">17 pages, 14 figures, Accepted for publication in Astronomy & Astrophysics, Data: https://doi.org/10.5281/zenodo.6461585</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 662, A81 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.08662">arXiv:2202.08662</a> <span> [<a href="https://arxiv.org/pdf/2202.08662">pdf</a>, <a href="https://arxiv.org/format/2202.08662">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> <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/10.1051/0004-6361/202142349">10.1051/0004-6361/202142349 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Gaia-ESO Survey: The analysis of the hot-star spectra </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Blomme%2C+R">R. Blomme</a>, <a href="/search/astro-ph?searchtype=author&query=Daflon%2C+S">S. Daflon</a>, <a href="/search/astro-ph?searchtype=author&query=Gebran%2C+M">M. Gebran</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Lobel%2C+A">A. Lobel</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Berlanas%2C+S+R">S. R. Berlanas</a>, <a href="/search/astro-ph?searchtype=author&query=Blazere%2C+A">A. Blazere</a>, <a href="/search/astro-ph?searchtype=author&query=Fremat%2C+Y">Y. Fremat</a>, <a href="/search/astro-ph?searchtype=author&query=Gosset%2C+E">E. Gosset</a>, <a href="/search/astro-ph?searchtype=author&query=Apellaniz%2C+J+M">J. Maiz Apellaniz</a>, <a href="/search/astro-ph?searchtype=author&query=Santos%2C+W">W. Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Semaan%2C+T">T. Semaan</a>, <a href="/search/astro-ph?searchtype=author&query=Simon-Diaz%2C+S">S. Simon-Diaz</a>, <a href="/search/astro-ph?searchtype=author&query=Volpi%2C+D">D. Volpi</a>, <a href="/search/astro-ph?searchtype=author&query=Holgado%2C+G">G. Holgado</a>, <a href="/search/astro-ph?searchtype=author&query=Jimenez-Esteban%2C+F">F. Jimenez-Esteban</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+F">M. F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Gilmore%2C+G">G. Gilmore</a>, <a href="/search/astro-ph?searchtype=author&query=Randich%2C+S">S. Randich</a>, <a href="/search/astro-ph?searchtype=author&query=Negueruela%2C+I">I. Negueruela</a>, <a href="/search/astro-ph?searchtype=author&query=Prusti%2C+T">T. Prusti</a> , et al. (22 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="2202.08662v2-abstract-short" style="display: inline;"> The Gaia-ESO Survey (GES) is a large public spectroscopic survey that has collected, over a period of 6 years, spectra of ~ 10^5 stars. This survey provides not only the reduced spectra, but also the stellar parameters and abundances resulting from the analysis of the spectra. The GES dataflow is organised in 19 working groups. Working group 13 (WG13) is responsible for the spectral analysis of th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08662v2-abstract-full').style.display = 'inline'; document.getElementById('2202.08662v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.08662v2-abstract-full" style="display: none;"> The Gaia-ESO Survey (GES) is a large public spectroscopic survey that has collected, over a period of 6 years, spectra of ~ 10^5 stars. This survey provides not only the reduced spectra, but also the stellar parameters and abundances resulting from the analysis of the spectra. The GES dataflow is organised in 19 working groups. Working group 13 (WG13) is responsible for the spectral analysis of the hottest stars (O, B and A type, with a formal cut-off of Teff > 7000 K) that were observed as part of GES. We present the procedures and techniques that have been applied to the reduced spectra, in order to determine the stellar parameters and abundances of these stars. The procedure used is similar to that of other working groups in GES. A number of groups (called `Nodes') each independently analyse the spectra, using their state-of-the-art techniques and codes. Specific for the analysis in WG13 is the large temperature range that is covered (Teff = 7000 - 50,000 K), requiring the use of different analysis codes. Most Nodes can therefore only handle part of the data. Quality checks are applied to the results of these Nodes by comparing them to benchmark stars, and by comparing them one to another. For each star the Node values are then homogenised into a single result: the recommended parameters and abundances. Eight Nodes each analysed (part of) the data. In total 17,693 spectra of 6462 stars were analysed, most of them in 37 open star clusters. The homogenisation led to stellar parameters for 5584 stars. Abundances were determined for a more limited number of stars. Elements studied are He, C, N, O, Ne, Mg, Al, Si and Sc. Abundances for at least one of those elements were determined for 292 stars. The hot-star data analysed here, as well as the Gaia-ESO Survey data in general, will be of considerable use in future studies of stellar evolution and open clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08662v2-abstract-full').style.display = 'none'; document.getElementById('2202.08662v2-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">26 pages, 14 figures, accepted for publication in Astronomy & Astrophysics; language-edited version; two appendices merged</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 661, A120 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.01311">arXiv:2201.01311</a> <span> [<a href="https://arxiv.org/pdf/2201.01311">pdf</a>, <a href="https://arxiv.org/format/2201.01311">other</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> <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/10.1051/0004-6361/202142372">10.1051/0004-6361/202142372 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MUSE crowded field 3D spectroscopy in NGC 300 II. Quantitative spectroscopy of BA-type supergiants </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez-Tor%C3%A0%2C+G">Gemma Gonz谩lez-Tor脿</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">Miguel A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Dreizler%2C+S">Stefan Dreizler</a>, <a href="/search/astro-ph?searchtype=author&query=Roth%2C+M+M">Martin M. Roth</a>, <a href="/search/astro-ph?searchtype=author&query=Kamann%2C+S">Sebastian Kamann</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">Norberto Castro</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="2201.01311v1-abstract-short" style="display: inline;"> A quantitative spectral analysis of BA-type supergiants and bright giants in an inner spiral arm region of the nearby spiral galaxy NGC 300 is presented, based on observations with the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Obsevatory, Very Large Telescope (ESO, VLT). The flux-weighted gravity-luminosity relationship (FGLR), a stellar spectroscopic distance determination… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.01311v1-abstract-full').style.display = 'inline'; document.getElementById('2201.01311v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.01311v1-abstract-full" style="display: none;"> A quantitative spectral analysis of BA-type supergiants and bright giants in an inner spiral arm region of the nearby spiral galaxy NGC 300 is presented, based on observations with the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Obsevatory, Very Large Telescope (ESO, VLT). The flux-weighted gravity-luminosity relationship (FGLR), a stellar spectroscopic distance determination method for galaxies, is extended towards stars at lower luminosities. Point spread function fitting 3D spectroscopy was performed with PampelMUSE on the datacube. The 16 stars with the highest signal-to-noise ratios ($S/N s$) are classified with regard to their spectral type and luminosity class using Galactic templates. They were analysed using hybrid non-local thermodynamic equilibrium (non-LTE) model spectra to fit the strongest observed hydrogen, helium, and metal lines in the intermediate-resolution spectra. Supplemented by photometric data, this facilitates fundamental stellar parameters and interstellar reddening which have yet to be determined. Effective temperatures, surface gravities, reddening $E(B-V)$, bolometric magnitudes and luminosities, as well as radii and masses are presented for the sample stars. The majority of the objects follow the FGLR as established from more luminous BA-type supergiants in NGC 300. An increase in the scatter in the flux-weighted gravity-luminosity plane is observed at these lower luminosities, which is in line with predictions from population synthesis models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.01311v1-abstract-full').style.display = 'none'; document.getElementById('2201.01311v1-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> 4 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">8 pages, 9 figures, 2 tables. Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 658, A117 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.11267">arXiv:2110.11267</a> <span> [<a href="https://arxiv.org/pdf/2110.11267">pdf</a>, <a href="https://arxiv.org/format/2110.11267">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/10.1051/0004-6361/202141625">10.1051/0004-6361/202141625 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> HD144941: The most extreme helium-strong star </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Jeffery%2C+C+S">C. S. Jeffery</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="2110.11267v1-abstract-short" style="display: inline;"> Since its discovery about 50 years ago, HD144941 has generally been classified as a peculiar member of the extreme helium (EHe) supergiant stars, a very rare class of low-mass hydrogen-deficient stars. We report the detection of a strong longitudinal magnetic field based on spectropolarimetry with FORS2 on the ESO VLT with surface-averaged longitudinal field strengths as large as -9kG. This is fur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.11267v1-abstract-full').style.display = 'inline'; document.getElementById('2110.11267v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.11267v1-abstract-full" style="display: none;"> Since its discovery about 50 years ago, HD144941 has generally been classified as a peculiar member of the extreme helium (EHe) supergiant stars, a very rare class of low-mass hydrogen-deficient stars. We report the detection of a strong longitudinal magnetic field based on spectropolarimetry with FORS2 on the ESO VLT with surface-averaged longitudinal field strengths as large as -9kG. This is further constrained by the detection of Zeeman splitting of spectral lines to a field strength of at least 15kG, explaining the recent finding of surface spots for this star. The quantitative analysis of the stellar atmosphere based on a hybrid non-local thermodynamic equilibrium approach and new optical spectra yields an effective temperature of 22000$\pm$500K, a logarithmic surface gravity of 4.20$\pm$0.10, and a surface helium fraction of 0.950$\pm$0.002 by number. While the metal abundances are about a factor of 10 sub-solar in absolute number, the metal-to-hydrogen ratios are typical of massive early-type stars, indicating that helium fallback in a weak, fractionated stellar wind in the presence of a magnetic field took place -- the canonical mechanism for the formation of the helium-strong phenomenon. Both the spectroscopic and the Gaia EDR3 parallax imply HD144941 to be a luminous massive star. Kinematically, we argue that HD144941 has reached its high Galactic latitude as a runaway star. We conclude that instead of being a comparatively high-gravity low-mass EHe star, HD144941 is by far the most extreme member of the magnetic massive helium-strong stars, with almost all atmospheric hydrogen substituted by helium. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.11267v1-abstract-full').style.display = 'none'; document.getElementById('2110.11267v1-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 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">9 pages, 8 figures, see A&A for the published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astronomy & Astrophysics 654 (2021) A119 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.03935">arXiv:2110.03935</a> <span> [<a href="https://arxiv.org/pdf/2110.03935">pdf</a>, <a href="https://arxiv.org/format/2110.03935">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/10.1051/0004-6361/202039787">10.1051/0004-6361/202039787 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> YY Hya and its interstellar environment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kimeswenger%2C+S">Stefan Kimeswenger</a>, <a href="/search/astro-ph?searchtype=author&query=Thorstensen%2C+J+R">John R. Thorstensen</a>, <a href="/search/astro-ph?searchtype=author&query=Fesen%2C+R+A">Robert A. Fesen</a>, <a href="/search/astro-ph?searchtype=author&query=Drechsler%2C+M">Marcel Drechsler</a>, <a href="/search/astro-ph?searchtype=author&query=Strottner%2C+X">Xavier Strottner</a>, <a href="/search/astro-ph?searchtype=author&query=Germiniani%2C+M">Maicon Germiniani</a>, <a href="/search/astro-ph?searchtype=author&query=Steindl%2C+T">Thomas Steindl</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Weil%2C+K+E">Kathryn E. Weil</a>, <a href="/search/astro-ph?searchtype=author&query=Rupert%2C+J">Justin Rupert</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="2110.03935v2-abstract-short" style="display: inline;"> During a search for previously unknown Galactic emission nebulae, we discovered a faint 36' diameter Halpha emission nebula centered around the periodic variable YY Hya. Although this star has been classified as RR-Lyr variable, such a classification is inconsistent Gaia distance of ~450 pc. GALEX image data also shows YY Hya to have a strong UV excess, suggesting the existence of a hot, compact b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.03935v2-abstract-full').style.display = 'inline'; document.getElementById('2110.03935v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.03935v2-abstract-full" style="display: none;"> During a search for previously unknown Galactic emission nebulae, we discovered a faint 36' diameter Halpha emission nebula centered around the periodic variable YY Hya. Although this star has been classified as RR-Lyr variable, such a classification is inconsistent Gaia distance of ~450 pc. GALEX image data also shows YY Hya to have a strong UV excess, suggesting the existence of a hot, compact binary companion. In addition to our discovery image data, we obtained image of the region with CHILESCOPE time-series spectroscopy at MDM observatory. Also, we used data from various space missions to derive an exact orbital period and a SED. We find that YY Hya is a compact binary system containing a K dwarf star which is strongly irradiated by a hot WD companion. The spectral characteristics of the emission lines, visible only during maximum light of the perfectly sinusoidal optical}light curve shows signatures much like members of the BE UMa variable family. These are post common envelope pre-cataclysmic variables. However the companion star here is more massive than found in other group members and the progenitor of the white dwarf must have been a 3 to 4 Mo star. The nebula seems to be an ejected common envelope shell with a mass in the order of one Mo and an age of 500000 years. This makes it to be the biggest hitherto known such shell. Alignment of neighboring nebulosities some 45' to the northeast and southwest of YY Hya suggests that the system had strong bipolar outflows. We briefly speculate it might be related to the 1065 BP "guest-star" reported in ancient Chinese records as well. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.03935v2-abstract-full').style.display = 'none'; document.getElementById('2110.03935v2-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 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">18 pages, 17 figures accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 656, A145 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.02878">arXiv:2108.02878</a> <span> [<a href="https://arxiv.org/pdf/2108.02878">pdf</a>, <a href="https://arxiv.org/format/2108.02878">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/10.1051/0004-6361/202141570">10.1051/0004-6361/202141570 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stellar labels for hot stars from low-resolution spectra - I. the HotPayne method and results for 330,000 stars from LAMOST DR6 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xiang%2C+M">Maosheng Xiang</a>, <a href="/search/astro-ph?searchtype=author&query=Rix%2C+H">Hans-Walter Rix</a>, <a href="/search/astro-ph?searchtype=author&query=Ting%2C+Y">Yuan-Sen Ting</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R">Rolf-Peter Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+C">Charlie Conroy</a>, <a href="/search/astro-ph?searchtype=author&query=Zari%2C+E">Eleonora Zari</a>, <a href="/search/astro-ph?searchtype=author&query=Shi%2C+J">Jian-Rong Shi</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Ramirez-Tannus%2C+M">Maria Ramirez-Tannus</a>, <a href="/search/astro-ph?searchtype=author&query=Tkachenko%2C+A">Andrew Tkachenko</a>, <a href="/search/astro-ph?searchtype=author&query=Gebruers%2C+S">Sarah Gebruers</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+X">Xiao-Wei Liu</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="2108.02878v1-abstract-short" style="display: inline;"> We set out to determine stellar labels from low-resolution survey spectra of hot, OBA stars with effective temperature (Teff) higher than 7500K. This fills a gap in the scientific analysis of large spectroscopic stellar surveys such as LAMOST, which offers spectra for millions of stars at R=1800. We first explore the theoretical information content of such spectra for determining stellar labels, v… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.02878v1-abstract-full').style.display = 'inline'; document.getElementById('2108.02878v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.02878v1-abstract-full" style="display: none;"> We set out to determine stellar labels from low-resolution survey spectra of hot, OBA stars with effective temperature (Teff) higher than 7500K. This fills a gap in the scientific analysis of large spectroscopic stellar surveys such as LAMOST, which offers spectra for millions of stars at R=1800. We first explore the theoretical information content of such spectra for determining stellar labels, via the Cram茅r-Rao bound. We show that in the limit of perfect model spectra and observed spectra with S/N of 100, precise estimates are possible for a wide range of stellar labels: not only the effective temperature Teff, surface gravity logg, and projected rotation velocity vsini, but also the micro-turbulence velocity, Helium abundance and the elemental abundances [C/H], [N/H], [O/H], [Si/H], [S/H], and [Fe/H]. Our analysis illustrates that the temperature regime of around 9500K is challenging, as the dominant Balmer and Paschen line strength vary little with Teff. We implement the simultaneous fitting of these 11 stellar labels to LAMOST hot-star spectra using the Payne approach, drawing on Kurucz's ATLAS12/SYNTHE LTE spectra as the underlying models. We then obtain stellar parameter estimates for a sample of about 330,000 hot stars with LAMOST spectra, an increase by about two orders of magnitude in sample size. Among them, about 260,000 have good Gaia parallaxes (S/N>5), and more than 95 percent of them are luminous stars, mostly on the main sequence; the rest reflects lower luminosity evolved stars, such as hot subdwarfs and white dwarfs. We show that the fidelity of the abundance estimates is limited by the systematics of the underlying models, as they do not account for NLTE effects. Finally, we show the detailed distribution of vsini of stars with 8000-15,000K, illustrating that it extends to a sharp cut-off at the critical rotation velocity, across a wide range of temperatures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.02878v1-abstract-full').style.display = 'none'; document.getElementById('2108.02878v1-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 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">30 pages, 22 figures, submitted to Astronomy & Astrophysics, comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 662, A66 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.10845">arXiv:2011.10845</a> <span> [<a href="https://arxiv.org/pdf/2011.10845">pdf</a>, <a href="https://arxiv.org/format/2011.10845">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.3847/1538-3881/abccd5">10.3847/1538-3881/abccd5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Refined Telluric Absorption Correction for Low-Resolution Ground-Based Spectroscopy: Resolution and Radial Velocity Effects in the O2 A-Band for Exoplanets and K I Emission Lines </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kimeswenger%2C+S">Stefan Kimeswenger</a>, <a href="/search/astro-ph?searchtype=author&query=Rainer%2C+M">Manuel Rainer</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Kausch%2C+W">Wolfgang Kausch</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.10845v1-abstract-short" style="display: inline;"> Telluric correction of spectroscopic observations is either performed via standard stars that are observed close in time and airmass along with the science target, or recently growing in importance, by theoretical telluric absorption modeling. Both approaches work fine when the telluric lines are resolved, i.e. at spectral resolving power larger than about 10000, and it is sufficient to facilitate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10845v1-abstract-full').style.display = 'inline'; document.getElementById('2011.10845v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.10845v1-abstract-full" style="display: none;"> Telluric correction of spectroscopic observations is either performed via standard stars that are observed close in time and airmass along with the science target, or recently growing in importance, by theoretical telluric absorption modeling. Both approaches work fine when the telluric lines are resolved, i.e. at spectral resolving power larger than about 10000, and it is sufficient to facilitate the detection of spectral features at lower resolution. However, a meaningful quantitative analysis requires also a reliable recovery of line strengths. Here, we show for the Fraunhofer A-band of molecular O2 that the standard telluric correction approach fails in this at lower spectral resolutions, as an example for the general problem. Doppler-shift dependent errors of the restored flux may arise, which can amount to more than 50% in extreme cases, depending on the line shapes of the target spectral features. Two applications are discussed: the recovery of the O2-band in the reflected light of an Earth analog atmosphere, as facilitated potentially in the future using an orbiting starshade and a ground-based extremely large telescope; and the recovery of the intrinsic ratio of the K I lines in the post-nova V4332 Sgr tracing the optical depth of the emitting region, to exemplify the relevance using present-day instrumentation. We show how one should derive correction functions for the compensation of the error in dependence of radial velocity shift, spectral resolution and target line-profile function by use of high resolution atmospheric transmission modeling, which has to be solved for the individual case. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10845v1-abstract-full').style.display = 'none'; document.getElementById('2011.10845v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 9 figures, accepted for publication in Astronomical Journal (AJ)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.10013">arXiv:2011.10013</a> <span> [<a href="https://arxiv.org/pdf/2011.10013">pdf</a>, <a href="https://arxiv.org/format/2011.10013">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/staa3661">10.1093/mnras/staa3661 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A quantitative in-depth analysis of the prototype sdB+BD system SDSS J08205+0008 revisited in the Gaia era </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schaffenroth%2C+V">V. Schaffenroth</a>, <a href="/search/astro-ph?searchtype=author&query=Casewell%2C+S+L">S. L. Casewell</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+D">D. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Kilkenny%2C+D">D. Kilkenny</a>, <a href="/search/astro-ph?searchtype=author&query=Geier%2C+S">S. Geier</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">U. Heber</a>, <a href="/search/astro-ph?searchtype=author&query=Irrgang%2C+A">A. Irrgang</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Marsh%2C+T+R">T. R. Marsh</a>, <a href="/search/astro-ph?searchtype=author&query=Littlefair%2C+S+P">S. P. Littlefair</a>, <a href="/search/astro-ph?searchtype=author&query=Dhillon%2C+V+S">V. S. Dhillon</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.10013v1-abstract-short" style="display: inline;"> Subdwarf B stars are core-helium burning stars located on the extreme horizontal branch. Extensive mass loss on the red giant branch is necessary to form them. It has been proposed that substellar companions could lead to the required mass-loss when they are engulfed in the envelope of the red giant star. J08205+0008 was the first example of a hot subdwarf star with a close, substellar companion c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10013v1-abstract-full').style.display = 'inline'; document.getElementById('2011.10013v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.10013v1-abstract-full" style="display: none;"> Subdwarf B stars are core-helium burning stars located on the extreme horizontal branch. Extensive mass loss on the red giant branch is necessary to form them. It has been proposed that substellar companions could lead to the required mass-loss when they are engulfed in the envelope of the red giant star. J08205+0008 was the first example of a hot subdwarf star with a close, substellar companion candidate to be found. Here we perform an in-depth re-analysis of this important system with much higher quality data allowing additional analysis methods. From the higher resolution spectra obtained with ESO-VLT/XSHOOTER we derive the chemical abundances of the hot subdwarf as well as its rotational velocity. Using the { it Gaia} parallax and a fit to the spectral energy distribution in the secondary eclipse, tight constraints to the radius of the hot subdwarf are derived. From a long-term photometric campaign we detected a significant period decrease of $-3.2(8)\cdot 10^{-12} \,\rm dd^{-1}$. This can be explained by the non-synchronised hot subdwarf star being spun up by tidal interactions forcing it to become synchronised. From the rate of period decrease we could derive the synchronisation timescale to be 4 Myr, much smaller than the lifetime on EHB. By combining all different methods we could constrain the hot subdwarf to a mass of $0.39-0.50\,\rm M_\odot$ and a radius of $R_{\rm sdB}=0.194\pm0.008\,\rm R_\odot$, and the companion to $0.061-0.071\rm\,M_\odot$ with a radius of $R_{\rm comp}=0.092 \pm 0.005\,\rm R_\odot$, below the hydrogen burning limit. We therefore confirm that the companion is most likely a massive brown dwarf. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.10013v1-abstract-full').style.display = 'none'; document.getElementById('2011.10013v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted to MNRAS, 25 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.08312">arXiv:1902.08312</a> <span> [<a href="https://arxiv.org/pdf/1902.08312">pdf</a>, <a href="https://arxiv.org/ps/1902.08312">ps</a>, <a href="https://arxiv.org/format/1902.08312">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/10.3847/2041-8213/ab095f">10.3847/2041-8213/ab095f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Asteroseismology of massive stars with the TESS mission: the runaway Beta Cep pulsator PHL 346 = HN Aqr </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Handler%2C+G">Gerald Handler</a>, <a href="/search/astro-ph?searchtype=author&query=Pigulski%2C+A">Andrzej Pigulski</a>, <a href="/search/astro-ph?searchtype=author&query=Daszy%C5%84ska-Daszkiewicz%2C+J">Jadwiga Daszy艅ska-Daszkiewicz</a>, <a href="/search/astro-ph?searchtype=author&query=Irrgang%2C+A">Andreas Irrgang</a>, <a href="/search/astro-ph?searchtype=author&query=Kilkenny%2C+D">David Kilkenny</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+Z">Zhao Guo</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Ali%C3%A7avu%C5%9F%2C+F+K">Filiz Kahraman Ali莽avu艧</a>, <a href="/search/astro-ph?searchtype=author&query=Kallinger%2C+T">Thomas Kallinger</a>, <a href="/search/astro-ph?searchtype=author&query=Pascual-Granado%2C+J">Javier Pascual-Granado</a>, <a href="/search/astro-ph?searchtype=author&query=Niemczura%2C+E">Ewa Niemczura</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%B3%C5%BCa%C5%84ski%2C+T">Tomasz R贸偶a艅ski</a>, <a href="/search/astro-ph?searchtype=author&query=Chowdhury%2C+S">Sowgata Chowdhury</a>, <a href="/search/astro-ph?searchtype=author&query=Buzasi%2C+D+L">Derek L. Buzasi</a>, <a href="/search/astro-ph?searchtype=author&query=Mirouh%2C+G+M">Giovanni M. Mirouh</a>, <a href="/search/astro-ph?searchtype=author&query=Bowman%2C+D+M">Dominic M. Bowman</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+C">Cole Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Pedersen%2C+M+G">May G. Pedersen</a>, <a href="/search/astro-ph?searchtype=author&query=Sim%C3%B3n-Diaz%2C+S">Sergio Sim贸n-Diaz</a>, <a href="/search/astro-ph?searchtype=author&query=Moravveji%2C+E">Ehsan Moravveji</a>, <a href="/search/astro-ph?searchtype=author&query=Gazeas%2C+K">Kosmas Gazeas</a>, <a href="/search/astro-ph?searchtype=author&query=De+Cat%2C+P">Peter De Cat</a>, <a href="/search/astro-ph?searchtype=author&query=Vanderspek%2C+R+K">Roland K. Vanderspek</a>, <a href="/search/astro-ph?searchtype=author&query=Ricker%2C+G+R">George R. Ricker</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="1902.08312v1-abstract-short" style="display: inline;"> We report an analysis of the first known Beta Cep pulsator observed by the TESS mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly-periodic pulsator, has at least 34 oscillation modes excited, 12 of those in the g-mode domain and 22 p modes. Analysis of archival data implies that the amplitude and frequency of the dominant mode and the stellar radial velocity were v… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.08312v1-abstract-full').style.display = 'inline'; document.getElementById('1902.08312v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.08312v1-abstract-full" style="display: none;"> We report an analysis of the first known Beta Cep pulsator observed by the TESS mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly-periodic pulsator, has at least 34 oscillation modes excited, 12 of those in the g-mode domain and 22 p modes. Analysis of archival data implies that the amplitude and frequency of the dominant mode and the stellar radial velocity were variable over time. A binary nature would be inconsistent with the inferred ejection velocity from the Galactic disc of 420 km/s, which is too large to be survivable by a runaway binary system. A kinematic analysis of the star results in an age constraint (23 +- 1 Myr) that can be imposed on asteroseismic modelling and that can be used to remove degeneracies in the modelling process. Our attempts to match the excitation of the observed frequency spectrum resulted in pulsation models that were too young. Hence, asteroseismic studies of runaway pulsators can become vital not only in tracing the evolutionary history of such objects, but to understand the interior structure of massive stars in general. TESS is now opening up these stars for detailed asteroseismic investigation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.08312v1-abstract-full').style.display = 'none'; document.getElementById('1902.08312v1-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 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">accepted for ApJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.02922">arXiv:1811.02922</a> <span> [<a href="https://arxiv.org/pdf/1811.02922">pdf</a>, <a href="https://arxiv.org/format/1811.02922">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/mnrasl/sly191">10.1093/mnrasl/sly191 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unravelling the baffling mystery of the ultrahot wind phenomenon in white dwarfs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Reindl%2C+N">Nicole Reindl</a>, <a href="/search/astro-ph?searchtype=author&query=Bainbridge%2C+M">M. Bainbridge</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Geier%2C+S">S. Geier</a>, <a href="/search/astro-ph?searchtype=author&query=Prv%C3%A1k%2C+M">M. Prv谩k</a>, <a href="/search/astro-ph?searchtype=author&query=Krti%C4%8Dka%2C+J">J. Krti膷ka</a>, <a href="/search/astro-ph?searchtype=author&query=%C3%98stensen%2C+R+H">R. H. 脴stensen</a>, <a href="/search/astro-ph?searchtype=author&query=Telting%2C+J">J. Telting</a>, <a href="/search/astro-ph?searchtype=author&query=Werner%2C+K">K. Werner</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="1811.02922v1-abstract-short" style="display: inline;"> The presence of ultra-high excitation (UHE) absorption lines (e.g., O VIII) in the optical spectra of several of the hottest white dwarfs poses a decades-long mystery and is something that has never been observed in any other astrophysical object. The occurrence of such features requires a dense environment with temperatures near $10^6$K, by far exceeding the stellar effective temperature. Here we… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02922v1-abstract-full').style.display = 'inline'; document.getElementById('1811.02922v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.02922v1-abstract-full" style="display: none;"> The presence of ultra-high excitation (UHE) absorption lines (e.g., O VIII) in the optical spectra of several of the hottest white dwarfs poses a decades-long mystery and is something that has never been observed in any other astrophysical object. The occurrence of such features requires a dense environment with temperatures near $10^6$K, by far exceeding the stellar effective temperature. Here we report the discovery of a new hot wind white dwarf, GALEXJ014636.8+323615. Astonishingly, we found for the first time rapid changes of the equivalent widths of the UHE features, which are correlated to the rotational period of the star ($P=0.242035$d). We explain this with the presence of a wind-fed circumstellar magnetosphere in which magnetically confined wind shocks heat up the material to the high temperatures required for the creation of the UHE lines. The photometric and spectroscopic variability of GALEXJ014636.8+323615 can then be understood as consequence of the obliquity of the magnetic axis with respect to the rotation axis of the white dwarf. This is the first time a wind-fed circumstellar magnetosphere around an apparently isolated white dwarf has been discovered and finally offers a plausible explanation of the ultra hot wind phenomenon. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02922v1-abstract-full').style.display = 'none'; document.getElementById('1811.02922v1-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, 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">Published in MNRAS Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2019, MNRAS Letters, 482, L93 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.04081">arXiv:1808.04081</a> <span> [<a href="https://arxiv.org/pdf/1808.04081">pdf</a>, <a href="https://arxiv.org/ps/1808.04081">ps</a>, <a href="https://arxiv.org/format/1808.04081">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/10.1051/0004-6361/201833171">10.1051/0004-6361/201833171 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of magnetic fields in He-rich early B-type stars using HARPSpol </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=J%C3%A4rvinen%2C+S+P">S. P. J盲rvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%B6ller%2C+M">M. Sch枚ller</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</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="1808.04081v1-abstract-short" style="display: inline;"> We focus on early-B type stars with helium overabundance, for which the presence of a magnetic field has not previously been reported. The measurements were carried out using high-spectral-resolution spectropolarimetric observations obtained with the High Accuracy Radial velocity Planet Searcher (HARPS) in polarimetric mode, installed at the ESO La Silla 3.6m telescope. For five He-rich stars, the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04081v1-abstract-full').style.display = 'inline'; document.getElementById('1808.04081v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.04081v1-abstract-full" style="display: none;"> We focus on early-B type stars with helium overabundance, for which the presence of a magnetic field has not previously been reported. The measurements were carried out using high-spectral-resolution spectropolarimetric observations obtained with the High Accuracy Radial velocity Planet Searcher (HARPS) in polarimetric mode, installed at the ESO La Silla 3.6m telescope. For five He-rich stars, the longitudinal magnetic field was detected for the first time. For one target, HD58260, the presence of a longitudinal magnetic field of the order of 1.8 kG has already been reported in the literature, but the magnetic field has remained constant over tens of years. Our measurement carried out using the polarimetric spectra obtained in 2015 March indicates a slight decrease of the longitudinal magnetic field strength compared to measurements reported in previous works. A search for periodic modulation in available photometric data allowed us to confidently establish a period of 2.64119$\pm$0.00420 d in archival ASAS3 data for CPD -27$^{\circ}$ 1791. No period could be determined for the other five stars. The obtained results support the scenario that all He-rich stars are detectably magnetic and form an extension of the Ap star phenomenon to higher temperatures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.04081v1-abstract-full').style.display = 'none'; document.getElementById('1808.04081v1-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 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted as A&A Letter</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 618, L2 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.10003">arXiv:1807.10003</a> <span> [<a href="https://arxiv.org/pdf/1807.10003">pdf</a>, <a href="https://arxiv.org/format/1807.10003">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 MICADO first light imager for the ELT: overview, operation, simulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Davies%2C+R">Richard Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Alves%2C+J">Jo茫o Alves</a>, <a href="/search/astro-ph?searchtype=author&query=Cl%C3%A9net%2C+Y">Yann Cl茅net</a>, <a href="/search/astro-ph?searchtype=author&query=Lang-Bardl%2C+F">Florian Lang-Bardl</a>, <a href="/search/astro-ph?searchtype=author&query=Nicklas%2C+H">Harald Nicklas</a>, <a href="/search/astro-ph?searchtype=author&query=Pott%2C+J">J枚rg-Uwe Pott</a>, <a href="/search/astro-ph?searchtype=author&query=Ragazzoni%2C+R">Roberto Ragazzoni</a>, <a href="/search/astro-ph?searchtype=author&query=Tolstoy%2C+E">Eline Tolstoy</a>, <a href="/search/astro-ph?searchtype=author&query=Amico%2C+P">Paola Amico</a>, <a href="/search/astro-ph?searchtype=author&query=Anwand-Heerwart%2C+H">Heiko Anwand-Heerwart</a>, <a href="/search/astro-ph?searchtype=author&query=Barboza%2C+S">Santiago Barboza</a>, <a href="/search/astro-ph?searchtype=author&query=Barl%2C+L">Lothar Barl</a>, <a href="/search/astro-ph?searchtype=author&query=Baudoz%2C+P">Pierre Baudoz</a>, <a href="/search/astro-ph?searchtype=author&query=Bender%2C+R">Ralf Bender</a>, <a href="/search/astro-ph?searchtype=author&query=Bezawada%2C+N">Naidu Bezawada</a>, <a href="/search/astro-ph?searchtype=author&query=Bizenberger%2C+P">Peter Bizenberger</a>, <a href="/search/astro-ph?searchtype=author&query=Boland%2C+W">Wilfried Boland</a>, <a href="/search/astro-ph?searchtype=author&query=Bonifacio%2C+P">Piercarlo Bonifacio</a>, <a href="/search/astro-ph?searchtype=author&query=Borgo%2C+B">Bruno Borgo</a>, <a href="/search/astro-ph?searchtype=author&query=Buey%2C+T">Tristan Buey</a>, <a href="/search/astro-ph?searchtype=author&query=Chapron%2C+F">Fr茅d茅ric Chapron</a>, <a href="/search/astro-ph?searchtype=author&query=Chemla%2C+F">Fanny Chemla</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+M">Mathieu Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Czoske%2C+O">Oliver Czoske</a>, <a href="/search/astro-ph?searchtype=author&query=Deo%2C+V">Vincent Deo</a> , et al. (76 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="1807.10003v1-abstract-short" style="display: inline;"> MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument's capabilities focus on imaging (including astrometric and high contrast) as well as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.10003v1-abstract-full').style.display = 'inline'; document.getElementById('1807.10003v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.10003v1-abstract-full" style="display: none;"> MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument's capabilities focus on imaging (including astrometric and high contrast) as well as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and making use of the data simulation tool, an outline is presented of what we can expect the instrument to achieve. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.10003v1-abstract-full').style.display = 'none'; document.getElementById('1807.10003v1-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 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Proc SPIE 10702. SPIE's copyright notice: "Copyright 2018 Society of PhotoOptical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited."</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.05888">arXiv:1807.05888</a> <span> [<a href="https://arxiv.org/pdf/1807.05888">pdf</a>, <a href="https://arxiv.org/format/1807.05888">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/10.3847/2041-8213/aad868">10.3847/2041-8213/aad868 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of extended main sequence turn offs in Galactic open clusters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marino%2C+A+F">A. F. Marino</a>, <a href="/search/astro-ph?searchtype=author&query=Milone%2C+A+P">A. P. Milone</a>, <a href="/search/astro-ph?searchtype=author&query=Casagrande%2C+L">L. Casagrande</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Balaguer-Nunez%2C+L">L. Balaguer-Nunez</a>, <a href="/search/astro-ph?searchtype=author&query=Di+Criscienzo%2C+M">M. Di Criscienzo</a>, <a href="/search/astro-ph?searchtype=author&query=Serenelli%2C+A">A. Serenelli</a>, <a href="/search/astro-ph?searchtype=author&query=Vilardell%2C+F">F. Vilardell</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="1807.05888v2-abstract-short" style="display: inline;"> By far, the color-magnitude diagrams (CMDs) of Galactic open clusters have been considered proto-types of single stellar populations. By using photometry in ultraviolet and optical bands we discovered that the nearby young cluster NGC6705 (M11) exhibits an extended main-sequence turn off (eMSTO) and a broadened main-sequence (MS). This is the first evidence of multiple stellar populations in a Gal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.05888v2-abstract-full').style.display = 'inline'; document.getElementById('1807.05888v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.05888v2-abstract-full" style="display: none;"> By far, the color-magnitude diagrams (CMDs) of Galactic open clusters have been considered proto-types of single stellar populations. By using photometry in ultraviolet and optical bands we discovered that the nearby young cluster NGC6705 (M11) exhibits an extended main-sequence turn off (eMSTO) and a broadened main-sequence (MS). This is the first evidence of multiple stellar populations in a Galactic open cluster. By using high-resolution VLT spectra we provide direct evidence that the multiple sequences along the CMD correspond to stellar populations with different rotation rates. Specifically, the blue MS is formed of slow-rotating stars, while red-MS stars are fast rotators. Moreover, we exploit photometry from Gaia DR2 to show that three Galactic open clusters, namely NGC2099, NGC2360, and NGC2818, exhibit the eMSTO, thus suggesting that it is a common feature among these objects. Our previous work on the Large Magellanic Cloud star cluster NGC1818 shows that slowly and fastly-rotating stars populate the blue and red MS observed in its CMD. The similarities between M11 and the young clusters of the Magellanic Clouds suggest that rotation is responsible for the appearance of multiple populations in the CMDs of both Milky Way open clusters and Magellanic Clouds young clusters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.05888v2-abstract-full').style.display = 'none'; document.getElementById('1807.05888v2-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 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">9 pages, 4 figures, Accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.04493">arXiv:1807.04493</a> <span> [<a href="https://arxiv.org/pdf/1807.04493">pdf</a>, <a href="https://arxiv.org/format/1807.04493">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/10.3847/1538-3881/aad3cd">10.3847/1538-3881/aad3cd <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Different stellar rotation in the two main sequences of the young globular cluster NGC1818: first direct spectroscopic evidence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Marino%2C+A+F">A. F. Marino</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Milone%2C+A+P">A. P. Milone</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Costa%2C+G">G. Da Costa</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Antona%2C+F">F. D'Antona</a>, <a href="/search/astro-ph?searchtype=author&query=Dotter%2C+A">A. Dotter</a>, <a href="/search/astro-ph?searchtype=author&query=Dupree%2C+A">A. Dupree</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="1807.04493v1-abstract-short" style="display: inline;"> We present a spectroscopic analysis of main sequence (MS) stars in the young globular cluster NGC1818 (age~40 Myrs) in the Large Magellanic Cloud. Our photometric survey on Magellanic Clouds clusters has revealed that NGC1818, similarly to the other young objects with age 600 Myrs, displays not only an extended MS Turn-Off (eMSTO), as observed in intermediate-age clusters (age~1-2 Gyrs), but also… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.04493v1-abstract-full').style.display = 'inline'; document.getElementById('1807.04493v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.04493v1-abstract-full" style="display: none;"> We present a spectroscopic analysis of main sequence (MS) stars in the young globular cluster NGC1818 (age~40 Myrs) in the Large Magellanic Cloud. Our photometric survey on Magellanic Clouds clusters has revealed that NGC1818, similarly to the other young objects with age 600 Myrs, displays not only an extended MS Turn-Off (eMSTO), as observed in intermediate-age clusters (age~1-2 Gyrs), but also a split MS. The most straightforward interpretation of the double MS is the presence of two stellar populations: a sequence of slowly-rotating stars lying on the blue-MS and a sequence of fast rotators, with rotation close to the breaking speed, defining a red-MS. We report the first direct spectroscopic measurements of projected rotational velocities vsini for the double MS, eMSTO and Be stars of a young cluster. The analysis of line profiles includes non-LTE effects, required for correctly deriving v sini values. Our results suggest that: (i) the mean rotation for blue- and red-MS stars is vsini=71\pm10 km/s (sigma=37 km/s) and vsini=202\pm23 km/s (sigma=91 km/s), respectively; (ii) eMSTO stars have different vsini, which are generally lower than those inferred for red-MS stars, and (iii) as expected, Be stars display the highest vsini values. This analyis supports the idea that distinct rotational velocities play an important role in the appearence of multiple stellar populations in the color-magnitude diagrams of young clusters, and poses new constraints to the current scenarios. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.04493v1-abstract-full').style.display = 'none'; document.getElementById('1807.04493v1-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 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">16 pages, 1 table, 9 figures. Accepted for publication in AJ (11/07/2018)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.07352">arXiv:1805.07352</a> <span> [<a href="https://arxiv.org/pdf/1805.07352">pdf</a>, <a href="https://arxiv.org/format/1805.07352">other</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> <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/10.3847/1538-4357/aac493">10.3847/1538-4357/aac493 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantitative Spectroscopy of Supergiants in the Local Group Dwarf Galaxy IC 1613: Metallicity and Distance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Berger%2C+T+A">Travis A. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R">Rolf-Peter Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">Miguel A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Bresolin%2C+F">Fabio Bresolin</a>, <a href="/search/astro-ph?searchtype=author&query=Gieren%2C+W">Wolfgang Gieren</a>, <a href="/search/astro-ph?searchtype=author&query=Pietrzy%C5%84ski%2C+G">Grzegorz Pietrzy艅ski</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</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="1805.07352v1-abstract-short" style="display: inline;"> We present the spectral analysis of 21 blue supergiant stars of spectral type late B to early A within the Local Group dwarf galaxy IC 1613 based on VLT-FORS2 low resolution spectra. Combining our results with studies of early B type blue supergiants we report a wide bi-modal distribution of metallicities with two peaks around [Z] $\sim -0.50$ dex and [Z] $\sim -0.85$ dex. The bi-modal distributio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.07352v1-abstract-full').style.display = 'inline'; document.getElementById('1805.07352v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.07352v1-abstract-full" style="display: none;"> We present the spectral analysis of 21 blue supergiant stars of spectral type late B to early A within the Local Group dwarf galaxy IC 1613 based on VLT-FORS2 low resolution spectra. Combining our results with studies of early B type blue supergiants we report a wide bi-modal distribution of metallicities with two peaks around [Z] $\sim -0.50$ dex and [Z] $\sim -0.85$ dex. The bi-modal distribution correlates with spatial location, when compared with column densities of neutral hydrogen in IC 1613. While the low [Z] objects appear in regions of relatively high ISM HI column densities or close to them, the high [Z] supergiants are found in the central HI hole almost devoid of hydrogen. This suggests varied chemical evolution histories of the young stellar populations in IC 1613. Utilizing the Flux-Weighted Gravity-Luminosity Relation (FGLR), we determine IC 1613's distance modulus as $m - M$ = 24.39 $\pm$ 0.11 mag. This value is in agreement within previous distance measurements using the near-infrared period-luminosity relationship of Cepheids and the tip of the red giant branch. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.07352v1-abstract-full').style.display = 'none'; document.getElementById('1805.07352v1-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 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">12 pages, 9 figures, 1 table. Accepted for publication in ApJ. For a brief video explaining this paper, see https://youtu.be/hsnU62pYsIQ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.00727">arXiv:1805.00727</a> <span> [<a href="https://arxiv.org/pdf/1805.00727">pdf</a>, <a href="https://arxiv.org/ps/1805.00727">ps</a>, <a href="https://arxiv.org/format/1805.00727">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/10.1051/0004-6361/201833087">10.1051/0004-6361/201833087 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On a new and homogeneous metallicity scale for Galactic classical Cepheids - I. Physical parameters </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Proxauf%2C+B">B. Proxauf</a>, <a href="/search/astro-ph?searchtype=author&query=da+Silva%2C+R">R. da Silva</a>, <a href="/search/astro-ph?searchtype=author&query=Kovtyukh%2C+V+V">V. V. Kovtyukh</a>, <a href="/search/astro-ph?searchtype=author&query=Bono%2C+G">G. Bono</a>, <a href="/search/astro-ph?searchtype=author&query=Inno%2C+L">L. Inno</a>, <a href="/search/astro-ph?searchtype=author&query=Lemasle%2C+B">B. Lemasle</a>, <a href="/search/astro-ph?searchtype=author&query=Pritchard%2C+J">J. Pritchard</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Storm%2C+J">J. Storm</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Valenti%2C+E">E. Valenti</a>, <a href="/search/astro-ph?searchtype=author&query=Bergemann%2C+M">M. Bergemann</a>, <a href="/search/astro-ph?searchtype=author&query=Buonanno%2C+R">R. Buonanno</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Orazi%2C+V">V. D'Orazi</a>, <a href="/search/astro-ph?searchtype=author&query=Fabrizio%2C+M">M. Fabrizio</a>, <a href="/search/astro-ph?searchtype=author&query=Ferraro%2C+I">I. Ferraro</a>, <a href="/search/astro-ph?searchtype=author&query=Fiorentino%2C+G">G. Fiorentino</a>, <a href="/search/astro-ph?searchtype=author&query=Francois%2C+P">P. Francois</a>, <a href="/search/astro-ph?searchtype=author&query=Iannicola%2C+G">G. Iannicola</a>, <a href="/search/astro-ph?searchtype=author&query=Laney%2C+C+D">C. D. Laney</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R+-">R. -P. Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Matsunaga%2C+N">N. Matsunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Nonino%2C+M">M. Nonino</a>, <a href="/search/astro-ph?searchtype=author&query=Primas%2C+F">F. Primas</a>, <a href="/search/astro-ph?searchtype=author&query=Romaniello%2C+M">M. Romaniello</a> , et al. (1 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="1805.00727v1-abstract-short" style="display: inline;"> We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To improve the effective temperature estimates, we present more than 150 new line depth ratio (LDR) calibrations that together with similar calibrations already avail… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.00727v1-abstract-full').style.display = 'inline'; document.getElementById('1805.00727v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.00727v1-abstract-full" style="display: none;"> We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To improve the effective temperature estimates, we present more than 150 new line depth ratio (LDR) calibrations that together with similar calibrations already available in the literature allowed us to cover a broad range in wavelength (between 5348 and 8427 angstrom) and in effective temperatures (between 3500 and 7700 K). This means the unique opportunity to cover both the hottest and coolest phases along the Cepheid pulsation cycle and to limit the intrinsic error on individual measurements at the level of ~100 K. Thanks to the high signal-to-noise ratio of individual spectra we identified and measured hundreds of neutral and ionized lines of heavy elements, and in turn, have the opportunity to trace the variation of both surface gravity and microturbulent velocity along the pulsation cycle. The accuracy of the physical parameters and the number of Fe I (more than one hundred) and Fe II (more than ten) lines measured allowed us to estimate mean iron abundances with a precision better than 0.1 dex. Here we focus on 14 calibrating Cepheids for which the current spectra cover either the entire or a significant portion of the pulsation cycle. The current estimates of the variation of the physical parameters along the pulsation cycle and of the iron abundances agree quite well with similar estimates available in the literature. Independent homogeneous estimates of both physical parameters and metal abundances based on different approaches that can constrain possible systematics are highly encouraged. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.00727v1-abstract-full').style.display = 'none'; document.getElementById('1805.00727v1-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 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">25 pages, 9 figures, 5 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 616, A82 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1804.03234">arXiv:1804.03234</a> <span> [<a href="https://arxiv.org/pdf/1804.03234">pdf</a>, <a href="https://arxiv.org/format/1804.03234">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/10.1051/0004-6361/201833182">10.1051/0004-6361/201833182 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> NLTE spectroscopic analysis of the $^3$He anomaly in subluminous B-type stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+D">D. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Irrgang%2C+A">A. Irrgang</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">U. Heber</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+F">M. F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</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="1804.03234v3-abstract-short" style="display: inline;"> Several B-type main-sequence stars show chemical peculiarities. A particularly striking class are the $^3$He stars, which exhibit a remarkable enrichment of $^3$He with respect to $^4$He. This isotopic anomaly has also been found in blue horizontal branch (BHB) and subdwarf B (sdB) stars, which are helium-core burning stars of the extreme horizontal branch. Using a hybrid local/non-local thermodyn… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.03234v3-abstract-full').style.display = 'inline'; document.getElementById('1804.03234v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1804.03234v3-abstract-full" style="display: none;"> Several B-type main-sequence stars show chemical peculiarities. A particularly striking class are the $^3$He stars, which exhibit a remarkable enrichment of $^3$He with respect to $^4$He. This isotopic anomaly has also been found in blue horizontal branch (BHB) and subdwarf B (sdB) stars, which are helium-core burning stars of the extreme horizontal branch. Using a hybrid local/non-local thermodynamic equilibrium (LTE/NLTE) approach for B-type stars, we analyzed high-quality spectra of two known $^3$He BHBs and nine known $^3$He sdBs to determine their isotopic helium abundances and $^4$He/$^3$He abundance ratios. We redetermined their atmospheric parameters and analyzed selected neutral helium lines, including $位$4922 $\mathring{A}$ and $位$6678 $\mathring{A}$, which are very sensitive to $^4$He/$^3$He. Most of the $^3$He sdBs cluster in a narrow temperature strip between 26000 K and 30000 K and are helium deficient in accordance with previous LTE analyses. BD+48$^\circ$ 2721 is reclassified as a BHB star because of its low temperature ($T_{\mathrm{eff}}=$ 20700 K). Whereas $^4$He is almost absent ($^4$He/$^3$He$<$ 0.25) in most of the known $^3$He stars, other sample stars show abundance ratios up to $^4$He/$^3$He$=$2.51. A search for $^3$He stars in the ESO SPY survey led to the discovery of two new $^3$He sdB stars (HE 0929-0424 and HE 1047-0436). The observed helium line profiles of all BHBs and of three sdBs are not matched by chemically homogeneous atmospheres, but hint at vertical helium stratification. This phenomenon has been seen in other peculiar B-type stars, but is found for the first time for sdBs. We estimate helium to increase from the outer to the inner atmosphere by factors ranging from 1.4 (SB 290) up to 8.0 (BD+48$^\circ$ 2721). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1804.03234v3-abstract-full').style.display = 'none'; document.getElementById('1804.03234v3-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 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 April, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">19 pages, 79 figures submitted to Astronomy&Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 618, A86 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1802.07314">arXiv:1802.07314</a> <span> [<a href="https://arxiv.org/pdf/1802.07314">pdf</a>, <a href="https://arxiv.org/ps/1802.07314">ps</a>, <a href="https://arxiv.org/format/1802.07314">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/10.3847/2041-8213/aab100">10.3847/2041-8213/aab100 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the chemical abundances of Miras in clusters: V1 in the metal-rich globular NGC 5927 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=D%27Orazi%2C+V">V. D'Orazi</a>, <a href="/search/astro-ph?searchtype=author&query=Magurno%2C+D">D. Magurno</a>, <a href="/search/astro-ph?searchtype=author&query=Bono%2C+G">G. Bono</a>, <a href="/search/astro-ph?searchtype=author&query=Matsunaga%2C+N">N. Matsunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Braga%2C+V+F">V. F. Braga</a>, <a href="/search/astro-ph?searchtype=author&query=Elgueta%2C+S+S">S. S. Elgueta</a>, <a href="/search/astro-ph?searchtype=author&query=Fukue%2C+K">K. Fukue</a>, <a href="/search/astro-ph?searchtype=author&query=Hamano%2C+S">S. Hamano</a>, <a href="/search/astro-ph?searchtype=author&query=Inno%2C+L">L. Inno</a>, <a href="/search/astro-ph?searchtype=author&query=Kobayashi%2C+N">N. Kobayashi</a>, <a href="/search/astro-ph?searchtype=author&query=Kondo%2C+S">S. Kondo</a>, <a href="/search/astro-ph?searchtype=author&query=Monelli%2C+M">M. Monelli</a>, <a href="/search/astro-ph?searchtype=author&query=Nonino%2C+M">M. Nonino</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+P+N">P. N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Sameshima%2C+H">H. Sameshima</a>, <a href="/search/astro-ph?searchtype=author&query=Saviane%2C+I">I. Saviane</a>, <a href="/search/astro-ph?searchtype=author&query=Taniguchi%2C+D">D. Taniguchi</a>, <a href="/search/astro-ph?searchtype=author&query=Thevenin%2C+F">F. Thevenin</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja-Perez%2C+M">M. Urbaneja-Perez</a>, <a href="/search/astro-ph?searchtype=author&query=Watase%2C+A">A. Watase</a>, <a href="/search/astro-ph?searchtype=author&query=Arai%2C+A">A. Arai</a>, <a href="/search/astro-ph?searchtype=author&query=Bergemann%2C+M">M. Bergemann</a>, <a href="/search/astro-ph?searchtype=author&query=Buonanno%2C+R">R. Buonanno</a>, <a href="/search/astro-ph?searchtype=author&query=Dall%27Ora%2C+M">M. Dall'Ora</a>, <a href="/search/astro-ph?searchtype=author&query=Silva%2C+R">R. Silva</a> , et al. (28 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="1802.07314v1-abstract-short" style="display: inline;"> We present the first spectroscopic abundance determination of iron, alpha-elements (Si, Ca and Ti) and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R~ 28,000), high signal-to-noise ratio (~200) spectra collected with WINERED, a near-infrared (NIR) spectrograph covering simultaneously the wavelength range 0.91--1.35 micron. The effective tempe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.07314v1-abstract-full').style.display = 'inline'; document.getElementById('1802.07314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1802.07314v1-abstract-full" style="display: none;"> We present the first spectroscopic abundance determination of iron, alpha-elements (Si, Ca and Ti) and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R~ 28,000), high signal-to-noise ratio (~200) spectra collected with WINERED, a near-infrared (NIR) spectrograph covering simultaneously the wavelength range 0.91--1.35 micron. The effective temperature and the surface gravity at the pulsation phase of the spectroscopic observation were estimated using both optical (V) and NIR time-series photometric data. We found that the Mira is metal-rich ([Fe/H]=-0.55 \pm 0.15) and moderately alpha-enhanced ([alpha/Fe]=0.15 \pm 0.01, sigma=0.2). These values agree quite well with the mean cluster abundances based on high-resolution optical spectra of several cluster red giants available in the literature ([Fe/H]=-0.47 \pm 0.06, [alpha/Fe]=+0.24 \pm 0.05). We also found a Na abundance of +0.35 \pm 0.20 that is higher than the mean cluster abundance based on optical spectra (+0.18 \pm 0.13). However, the lack of similar spectra for cluster red giants and that of corrections for departures from local-thermodynamical equilibrium prevents us from establishing whether the difference is intrinsic or connected with multiple populations. These findings indicate a strong similarity between optical and NIR metallicity scales in spite of the difference in the experimental equipment, data analysis and in the adopted spectroscopic diagnostics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.07314v1-abstract-full').style.display = 'none'; document.getElementById('1802.07314v1-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 February, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the Astrophysical Journal Letters, 9 pages, 3 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/1707.09017">arXiv:1707.09017</a> <span> [<a href="https://arxiv.org/pdf/1707.09017">pdf</a>, <a href="https://arxiv.org/ps/1707.09017">ps</a>, <a href="https://arxiv.org/format/1707.09017">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/stx1654">10.1093/mnras/stx1654 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic field geometry and chemical abundance distribution of the He-strong star CPD -57 3509 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Korhonen%2C+H">H. Korhonen</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%B6ller%2C+M">M. Sch枚ller</a>, <a href="/search/astro-ph?searchtype=author&query=Jarvinen%2C+S+P">S. P. Jarvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Scholz%2C+R+-">R. -D. Scholz</a>, <a href="/search/astro-ph?searchtype=author&query=Kimeswenger%2C+S">S. Kimeswenger</a>, <a href="/search/astro-ph?searchtype=author&query=Ramolla%2C+M">M. Ramolla</a>, <a href="/search/astro-ph?searchtype=author&query=Kholtygin%2C+A+F">A. F. Kholtygin</a>, <a href="/search/astro-ph?searchtype=author&query=Briquet%2C+M">M. Briquet</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="1707.09017v1-abstract-short" style="display: inline;"> The magnetic field of CPD -57 3509 was recently detected in the framework of the BOB (B fields in OB stars) collaboration. We acquired low-resolution spectropolarimetric observations of CPD -57 3509 with FORS2 and high-resolution UVES observations randomly distributed over a few months to search for periodicity, to study the magnetic field geometry, and to determine the surface distribution of sil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.09017v1-abstract-full').style.display = 'inline'; document.getElementById('1707.09017v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.09017v1-abstract-full" style="display: none;"> The magnetic field of CPD -57 3509 was recently detected in the framework of the BOB (B fields in OB stars) collaboration. We acquired low-resolution spectropolarimetric observations of CPD -57 3509 with FORS2 and high-resolution UVES observations randomly distributed over a few months to search for periodicity, to study the magnetic field geometry, and to determine the surface distribution of silicon and helium. We also obtained supplementary photometric observations at a timeline similar to the spectroscopic and spectropolarimetric observations. A period of 6.36d was detected in the measurements of the mean longitudinal magnetic field. A sinusoidal fit to our measurements allowed us to constrain the magnetic field geometry and estimate the dipole strength in the range of 3.9-4.5kG. Our application of the Doppler imaging technique revealed the presence of He I spots located around the magnetic poles, with a strong concentration at the positive pole and a weaker one around the negative pole. In contrast, high concentration Si III spots are located close to the magnetic equator. Further, our analysis of the spectral variability of CPD -57 3509 on short time scales indicates distinct changes in shape and position of line profiles possibly caused by the presence of beta Cep-like pulsations. A small periodic variability in line with the changes of the magnetic field strength is clearly seen in the photometric data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.09017v1-abstract-full').style.display = 'none'; document.getElementById('1707.09017v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 5 tables, 7 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/1707.07920">arXiv:1707.07920</a> <span> [<a href="https://arxiv.org/pdf/1707.07920">pdf</a>, <a href="https://arxiv.org/ps/1707.07920">ps</a>, <a href="https://arxiv.org/format/1707.07920">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="Earth and Planetary Astrophysics">astro-ph.EP</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201731384">10.1051/0004-6361/201731384 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Candidate exoplanet host HD131399A: a nascent Am star </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Aschenbrenner%2C+P">P. Aschenbrenner</a>, <a href="/search/astro-ph?searchtype=author&query=Buder%2C+S">S. Buder</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="1707.07920v1-abstract-short" style="display: inline;"> Direct imaging suggests that there is a Jovian exoplanet around the primary A-star in the triple-star system HD131399. We investigate a high-quality spectrum of the primary component HD131399A obtained with FEROS on the ESO/MPG 2.2m telescope, aiming to characterise the star's atmospheric and fundamental parameters, and to determine elemental abundances at high precision and accuracy. The aim is t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.07920v1-abstract-full').style.display = 'inline'; document.getElementById('1707.07920v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.07920v1-abstract-full" style="display: none;"> Direct imaging suggests that there is a Jovian exoplanet around the primary A-star in the triple-star system HD131399. We investigate a high-quality spectrum of the primary component HD131399A obtained with FEROS on the ESO/MPG 2.2m telescope, aiming to characterise the star's atmospheric and fundamental parameters, and to determine elemental abundances at high precision and accuracy. The aim is to constrain the chemical composition of the birth cloud of the system and therefore the bulk composition of the putative planet. A hybrid non-local thermal equilibrium (non-LTE) model atmosphere technique is adopted for the quantitative spectral analysis. Comparison with the most recent stellar evolution models yields the fundamental parameters. The atmospheric and fundamental stellar parameters of HD131399A are constrained to Teff=9200+-100 K, log g=4.37+-0.10, M=1.95+0.08-0.06 Msun, R=1.51+0.13-0.10 Rsun, and log L/Lsun=1.17+-0.07, locating the star on the zero-age main sequence. Non-LTE effects on the derived metal abundances are often smaller than 0.1dex, but can reach up to ~0.8dex for individual lines. The observed lighter elements up to calcium are overall consistent with present-day cosmic abundances, with a C/O ratio of 0.45$\pm$0.07 by number, while the heavier elements show mild overabundances. We conclude that the birth cloud of the system had a standard chemical composition, but we witness the onset of the Am phenomenon in the slowly rotating star. We furthermore show that non-LTE analyses have the potential to solve the remaining discrepancies between observed abundances and predictions by diffusion models for Am stars. Moreover, the present case allows mass loss, not turbulent mixing, to be identified as the main transport process competing with diffusion in very young Am stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.07920v1-abstract-full').style.display = 'none'; document.getElementById('1707.07920v1-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 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages + 3 pages appendix, 3 figures. Accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.00560">arXiv:1707.00560</a> <span> [<a href="https://arxiv.org/pdf/1707.00560">pdf</a>, <a href="https://arxiv.org/format/1707.00560">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/stx1549">10.1093/mnras/stx1549 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discovery of magnetic A supergiants: the descendants of magnetic main sequence B stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">Coralie Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Oksala%2C+M+E">Mary E. Oksala</a>, <a href="/search/astro-ph?searchtype=author&query=Georgy%2C+C">Cyril Georgy</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Mathis%2C+S">St茅phane Mathis</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G">Gregg Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Kondrak%2C+M">Matthias Kondrak</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">Luca Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Blaz%C3%A8re%2C+A">Aurore Blaz猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Buysschaert%2C+B">Bram Buysschaert</a>, <a href="/search/astro-ph?searchtype=author&query=Grunhut%2C+J">Jason Grunhut</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="1707.00560v1-abstract-short" style="display: inline;"> In the context of the high resolution, high signal-to-noise ratio, high sensitivity, spectropolarimetric survey BritePol, which complements observations by the BRITE constellation of nanosatellites for asteroseismology, we are looking for and measuring the magnetic field of all stars brighter than V=4. In this paper, we present circularly polarised spectra obtained with HarpsPol at ESO in La Silla… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.00560v1-abstract-full').style.display = 'inline'; document.getElementById('1707.00560v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.00560v1-abstract-full" style="display: none;"> In the context of the high resolution, high signal-to-noise ratio, high sensitivity, spectropolarimetric survey BritePol, which complements observations by the BRITE constellation of nanosatellites for asteroseismology, we are looking for and measuring the magnetic field of all stars brighter than V=4. In this paper, we present circularly polarised spectra obtained with HarpsPol at ESO in La Silla (Chile) and ESPaDOnS at CFHT (Hawaii) for 3 hot evolved stars: $喂$ Car, HR 3890, and $蔚$ CMa. We detected a magnetic field in all 3 stars. Each star has been observed several times to confirm the magnetic detections and check for variability. The stellar parameters of the 3 objects were determined and their evolutionary status was ascertained employing evolution models computed with the Geneva code. $蔚$ CMa was already known and is confirmed to be magnetic, but our modeling indicates that it is located near the end of the main sequence, i.e. it is still in a core hydrogen burning phase. $喂$ Car and HR 3890 are the first discoveries of magnetic hot supergiants located well after the end of the main sequence on the HR diagram. These stars are probably the descendants of main sequence magnetic massive stars. Their current field strength (a few G) is compatible with magnetic flux conservation during stellar evolution. These results provide observational constraints for the development of future evolutionary models of hot stars including a fossil magnetic field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.00560v1-abstract-full').style.display = 'none'; document.getElementById('1707.00560v1-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 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 5 figures, 3 tables, in press 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/1706.05389">arXiv:1706.05389</a> <span> [<a href="https://arxiv.org/pdf/1706.05389">pdf</a>, <a href="https://arxiv.org/ps/1706.05389">ps</a>, <a href="https://arxiv.org/format/1706.05389">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/stx1541">10.1093/mnras/stx1541 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantitative spectroscopy of extreme helium stars - Model atmospheres and a non-LTE abundance analysis of BD+10$^\circ$2179? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kupfer%2C+T">Thomas Kupfer</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Heber%2C+U">Ulrich Heber</a>, <a href="/search/astro-ph?searchtype=author&query=Jeffery%2C+C+S">C. Simon Jeffery</a>, <a href="/search/astro-ph?searchtype=author&query=Behara%2C+N+T">N. T. Behara</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">Keith Butler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1706.05389v1-abstract-short" style="display: inline;"> Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10$^\circ$2179, a prototype of this rare class of stars, using UVES and FEROS spectra covering the range from $\sim$3100 to 10 000 脜. Atmosphere model co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.05389v1-abstract-full').style.display = 'inline'; document.getElementById('1706.05389v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.05389v1-abstract-full" style="display: none;"> Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10$^\circ$2179, a prototype of this rare class of stars, using UVES and FEROS spectra covering the range from $\sim$3100 to 10 000 脜. Atmosphere model computations were improved in two ways. First, since the UV metal line blanketing has a strong impact on the temperature-density stratification, we used the Atlas12 code. Additionally, We tested Atlas12 against the benchmark code Sterne3, and found only small differences in the temperature and density stratifications, and good agreement with the spectral energy distributions. Second, 12 chemical species were treated in non-LTE. Pronounced non-LTE effects occur in individual spectral lines but, for the majority, the effects are moderate to small. The spectroscopic parameters give $T_\mathrm{eff}$ = 17 300$\pm$300 K and $\log g$ = 2.80$\pm$0.10, and an evolutionary mass of 0.55$\pm$0.05 $M_\odot$. The star is thus slightly hotter, more compact and less massive than found in previous studies. The kinematic properties imply a thick-disk membership, which is consistent with the metallicity $[$Fe/H$]\approx-1$ and $伪$-enhancement. The refined light-element abundances are consistent with the white dwarf merger scenario. We further discuss the observed helium spectrum in an appendix, detecting dipole-allowed transitions from about 150 multiplets plus the most comprehensive set of known/predicted isolated forbidden components to date. Moreover, a so far unreported series of pronounced forbidden He I components is detected in the optical-UV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.05389v1-abstract-full').style.display = 'none'; document.getElementById('1706.05389v1-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 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">Accepted for publication in MNRAS, 26 pages, 19 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/1706.03967">arXiv:1706.03967</a> <span> [<a href="https://arxiv.org/pdf/1706.03967">pdf</a>, <a href="https://arxiv.org/format/1706.03967">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/10.3847/1538-3881/aa79a8">10.3847/1538-3881/aa79a8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> LMC Blue Supergiant Stars and the Calibration of the Flux-weighted Gravity--Luminosity Relationship </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R+P">R. P. Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Gieren%2C+W">W. Gieren</a>, <a href="/search/astro-ph?searchtype=author&query=Pietrzynski%2C+G">G. Pietrzynski</a>, <a href="/search/astro-ph?searchtype=author&query=Bresolin%2C+F">F. Bresolin</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</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="1706.03967v1-abstract-short" style="display: inline;"> High quality spectra of 90 blue supergiant stars in the Large Magellanic Cloud are analyzed with respect to effective temperature, gravity, metallicity, reddening, extinction and extinction law. An average metallicity, based on Fe and Mg abundances, relative to the Sun of [Z] = -0.35 +/- 0.09 dex is obtained. The reddening distribution peaks at E(B-V) = 0.08 mag, but significantly larger values ar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.03967v1-abstract-full').style.display = 'inline'; document.getElementById('1706.03967v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.03967v1-abstract-full" style="display: none;"> High quality spectra of 90 blue supergiant stars in the Large Magellanic Cloud are analyzed with respect to effective temperature, gravity, metallicity, reddening, extinction and extinction law. An average metallicity, based on Fe and Mg abundances, relative to the Sun of [Z] = -0.35 +/- 0.09 dex is obtained. The reddening distribution peaks at E(B-V) = 0.08 mag, but significantly larger values are also encountered. A wide distribution of the ratio of extinction to reddening is found ranging from Rv = 2 to 6. The results are used to investigate the blue supergiant relationship between flux-weighted gravity, and absolute bolometric magnitude. The existence of a tight relationship, the FGLR, is confirmed. However, in contrast to previous work the observations reveal that the FGLR is divided into two parts with a different slope. For flux-weighted gravities larger than 1.30 dex the slope is similar as found in previous work, but the relationship becomes significantly steeper for smaller values of the flux-weighted gravity. A new calibration of the FGLR for extragalactic distance determinations is provided. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.03967v1-abstract-full').style.display = 'none'; document.getElementById('1706.03967v1-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 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">Accepted for publication by AJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.06456">arXiv:1703.06456</a> <span> [<a href="https://arxiv.org/pdf/1703.06456">pdf</a>, <a href="https://arxiv.org/format/1703.06456">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/10.1051/0004-6361/201630327">10.1051/0004-6361/201630327 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A comprehensive study of young B stars in NGC 2264: I. Space photometry and asteroseismology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zwintz%2C+K">K. Zwintz</a>, <a href="/search/astro-ph?searchtype=author&query=Moravveji%2C+E">E. Moravveji</a>, <a href="/search/astro-ph?searchtype=author&query=Papics%2C+P+I">P. I. Papics</a>, <a href="/search/astro-ph?searchtype=author&query=Tkachenko%2C+A">A. Tkachenko</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Kuschnig%2C+R">R. Kuschnig</a>, <a href="/search/astro-ph?searchtype=author&query=Antoci%2C+V">V. Antoci</a>, <a href="/search/astro-ph?searchtype=author&query=Lorenz%2C+D">D. Lorenz</a>, <a href="/search/astro-ph?searchtype=author&query=Themessl%2C+N">N. Themessl</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+T+G">T. G. Barnes</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="1703.06456v1-abstract-short" style="display: inline;"> Space photometric time series of the most massive members of the young open cluster NGC 2264 allow us to study their different sources of variability down to the millimagnitude level and permits a search for Slowly Pulsating B (SPB) type pulsation among objects that are only a few million years old. Our goal is to conduct a homogeneous study of young B type stars in the cluster NGC 2264 using phot… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.06456v1-abstract-full').style.display = 'inline'; document.getElementById('1703.06456v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.06456v1-abstract-full" style="display: none;"> Space photometric time series of the most massive members of the young open cluster NGC 2264 allow us to study their different sources of variability down to the millimagnitude level and permits a search for Slowly Pulsating B (SPB) type pulsation among objects that are only a few million years old. Our goal is to conduct a homogeneous study of young B type stars in the cluster NGC 2264 using photometric time series from space in combination with high-resolution spectroscopy and spectropolarimetry obtained from the ground. The latter will be presented in a separate follow-up article. We performed frequency analyses for eleven B stars in the field of the young cluster NGC 2264 using photometric time series from the MOST, CoRoT and Spitzer space telescopes and the routines Period04 and SigSpec. We employ the MESA stellar evolution code in combination with the oscillation code GYRE to identify the pulsation modes for two SPB stars which exhibit short period spacing series. From our analysis we identify four objects that show SPB pulsations, five stars that show rotational modulation of their light curves caused by spots, one star that is identified to be a binary, and one object in the field of the cluster that is found to be a non-member Be star. In two SPB stars we detect a number of regularly spaced pulsation modes that are compatible with being members of a g mode period series. Despite NGC 2264's young age, our analysis illustrates that its B type members have already arrived on the zero-age main sequence (ZAMS). Our asteroseismic analysis yields masses between 4 and 6 Msun and ages between 1 and 6 million years, which agree well to the overall cluster age. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.06456v1-abstract-full').style.display = 'none'; document.getElementById('1703.06456v1-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 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">19 pages, 20 figures, accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 601, A101 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.00720">arXiv:1703.00720</a> <span> [<a href="https://arxiv.org/pdf/1703.00720">pdf</a>, <a href="https://arxiv.org/format/1703.00720">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/S1743921317003167">10.1017/S1743921317003167 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Highly accurate quantitative spectroscopy of massive stars in the Galaxy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M">Maria-Fernanda Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</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="1703.00720v1-abstract-short" style="display: inline;"> Achieving high accuracy and precision in stellar parameter and chemical composition determinations is challenging in massive star spectroscopy. On one hand, the target selection for an unbiased sample build-up is complicated by several types of peculiarities that can occur in individual objects. On the other hand, composite spectra are often not recognized as such even at medium-high spectral reso… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.00720v1-abstract-full').style.display = 'inline'; document.getElementById('1703.00720v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.00720v1-abstract-full" style="display: none;"> Achieving high accuracy and precision in stellar parameter and chemical composition determinations is challenging in massive star spectroscopy. On one hand, the target selection for an unbiased sample build-up is complicated by several types of peculiarities that can occur in individual objects. On the other hand, composite spectra are often not recognized as such even at medium-high spectral resolution and typical signal-to-noise ratios, despite multiplicity among massive stars is widespread. In particular, surveys that produce large amounts of automatically reduced data are prone to oversight of details that turn hazardous for the analysis with techniques that have been developed for a set of standard assumptions applicable to a spectrum of a single star. Much larger systematic errors than anticipated may therefore result because of the unrecognized true nature of the investigated objects, or much smaller sample sizes of objects for the analysis than initially planned, if recognized. More factors to be taken care of are the multiple steps from the choice of instrument over the details of the data reduction chain to the choice of modelling code, input data, analysis technique and the selection of the spectral lines to be analyzed. Only when avoiding all the possible pitfalls, a precise and accurate characterization of the stars in terms of fundamental parameters and chemical fingerprints can be achieved that form the basis for further investigations regarding e.g. stellar structure and evolution or the chemical evolution of the Galaxy. The scope of the present work is to provide the broader community with criteria to evaluate spectroscopic investigations of massive stars before interpreting them in a broader context. The discussion is guided by our experiences made over a decade of studies of massive star spectroscopy ranging from the simplest single objects to multiple systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.00720v1-abstract-full').style.display = 'none'; document.getElementById('1703.00720v1-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 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 7 figures, conference proceeding (invited talk), IAUS 329: The lives and death-throes of massive stars, J.J. Eldridge, L. McClelland, L. Xiao & J. Bray, eds</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.06924">arXiv:1702.06924</a> <span> [<a href="https://arxiv.org/pdf/1702.06924">pdf</a>, <a href="https://arxiv.org/format/1702.06924">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/S1743921317003040">10.1017/S1743921317003040 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The evolution of magnetic fields in hot stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Oksala%2C+M+E">Mary E. Oksala</a>, <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">Coralie Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Georgy%2C+C">Cyril Georgy</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Zsolt Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G">Gregg Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Mathis%2C+S">St茅phane Mathis</a>, <a href="/search/astro-ph?searchtype=author&query=Blaz%C3%A8re%2C+A">Aurore Blaz猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Buysschaert%2C+B">Bram Buysschaert</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="1702.06924v1-abstract-short" style="display: inline;"> Over the last decade, tremendous strides have been achieved in our understanding of magnetism in main sequence hot stars. In particular, the statistical occurrence of their surface magnetism has been established (~10%) and the field origin is now understood to be fossil. However, fundamental questions remain: how do these fossil fields evolve during the post-main sequence phases, and how do they i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06924v1-abstract-full').style.display = 'inline'; document.getElementById('1702.06924v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.06924v1-abstract-full" style="display: none;"> Over the last decade, tremendous strides have been achieved in our understanding of magnetism in main sequence hot stars. In particular, the statistical occurrence of their surface magnetism has been established (~10%) and the field origin is now understood to be fossil. However, fundamental questions remain: how do these fossil fields evolve during the post-main sequence phases, and how do they influence the evolution of hot stars from the main sequence to their ultimate demise? Filling the void of known magnetic evolved hot (OBA) stars, studying the evolution of their fossil magnetic fields along stellar evolution, and understanding the impact of these fields on the angular momentum, rotation, mass loss, and evolution of the star itself, is crucial to answering these questions, with far reaching consequences, in particular for the properties of the precursors of supernovae explosions and stellar remnants. In the framework of the BRITE spectropolarimetric survey and LIFE project, we have discovered the first few magnetic hot supergiants. Their longitudinal surface magnetic field is very weak but their configuration resembles those of main sequence hot stars. We present these first observational results and propose to interpret them at first order in the context of magnetic flux conservation as the radius of the star expands with evolution. We then also consider the possible impact of stellar structure changes along evolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06924v1-abstract-full').style.display = 'none'; document.getElementById('1702.06924v1-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> 22 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">5 pages, 2 figures, IAUS 329 conference proceeding</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1701.03514">arXiv:1701.03514</a> <span> [<a href="https://arxiv.org/pdf/1701.03514">pdf</a>, <a href="https://arxiv.org/ps/1701.03514">ps</a>, <a href="https://arxiv.org/format/1701.03514">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/stx105">10.1093/mnras/stx105 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B fields in OB stars (BOB): The magnetic triple stellar system HD 164492C in the Trifid nebula </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+J+F">J. F. Gonzalez</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Carroll%2C+T">T. Carroll</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Jarvinen%2C+S">S. Jarvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Schoeller%2C+M">M. Schoeller</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Barba%2C+R">R. Barba</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=Schneider%2C+F+R+N">F. R. N. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Kholtygin%2C+A">A. Kholtygin</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=Veramendi%2C+M+E">M. E. Veramendi</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+t+B">the BOB 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="1701.03514v1-abstract-short" style="display: inline;"> HD 164492C is a spectroscopic triple stellar system that has been recently detected to possess a strong magnetic field. We have obtained high-resolution spectroscopic and spectropolarimetric observations over a timespan of two years and derived physical, chemical, and magnetic properties for this object. The system is formed by an eccentric close spectroscopic binary (Ca1-Ca2) with a period of 12.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.03514v1-abstract-full').style.display = 'inline'; document.getElementById('1701.03514v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1701.03514v1-abstract-full" style="display: none;"> HD 164492C is a spectroscopic triple stellar system that has been recently detected to possess a strong magnetic field. We have obtained high-resolution spectroscopic and spectropolarimetric observations over a timespan of two years and derived physical, chemical, and magnetic properties for this object. The system is formed by an eccentric close spectroscopic binary (Ca1-Ca2) with a period of 12.5 days, and a massive tertiary Cb. We calculated the orbital parameters of the close pair, reconstructed the spectra of the three components, and determined atmospheric parameters and chemical abundances by spectral synthesis. From spectropolarimetric observations, multi-epoch measurements of the longitudinal magnetic fields were obtained. The magnetic field is strongly variable on timescales of a few days, with a most probable period in the range of 1.4-1.6 days. Star Cb with Teff~25000 K is the apparently fastest rotator and the most massive star of this triple system and has anomalous chemical abundances with a marked overabundance of helium, 0.35+/-0.04 by number. We identified this star as being responsible for the observed magnetic field, although the presence of magnetic fields in the components of the Ca pair cannot be excluded. Star Ca1 with a temperature of about 24000 K presents a normal chemical pattern, while the least massive star Ca2 is a mid-B type star (Teff~15000 K) with an overabundance of silicon. The obtained stellar parameters of the system components suggest a distance of 1.5 kpc and an age of 10-15 Myr. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.03514v1-abstract-full').style.display = 'none'; document.getElementById('1701.03514v1-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 January, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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, 5 tables, 12 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/1612.01537">arXiv:1612.01537</a> <span> [<a href="https://arxiv.org/pdf/1612.01537">pdf</a>, <a href="https://arxiv.org/format/1612.01537">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/10.1051/0004-6361/201629751">10.1051/0004-6361/201629751 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B field in OB stars (BOB): The outstandingly strong magnetic field in the evolved He-strong star CPD-62 2124 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=J%C3%A4rvinen%2C+S+P">S. P. J盲rvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Carroll%2C+T+A">T. A. Carroll</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%B6ller%2C+M">M. Sch枚ller</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">F. R. N. Schneider</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=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+t+B">the BOB 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="1612.01537v1-abstract-short" style="display: inline;"> The origin and evolution of magnetism in OB stars is far from being well understood. With approximately 70 magnetic OB stars known, any new object with unusual characteristics may turn out to be a key piece of the puzzle. We report the detection of an exceptionally strong magnetic field in the He-strong B2IV star CPD-62 2124. Spectropolarimetric FORS2 and HARPSpol observations were analysed by two… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.01537v1-abstract-full').style.display = 'inline'; document.getElementById('1612.01537v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.01537v1-abstract-full" style="display: none;"> The origin and evolution of magnetism in OB stars is far from being well understood. With approximately 70 magnetic OB stars known, any new object with unusual characteristics may turn out to be a key piece of the puzzle. We report the detection of an exceptionally strong magnetic field in the He-strong B2IV star CPD-62 2124. Spectropolarimetric FORS2 and HARPSpol observations were analysed by two independent teams and procedures, concluding on a strong longitudinal magnetic field of approximately 5.2 kG. The quantitative characterisation of the stellar atmosphere yields an effective temperature of 23650$\pm$250 K, a surface gravity of 3.95$\pm$0.10 dex and a surface helium fraction of 0.35$\pm$0.02 by number. The metal composition is in agreement with the cosmic abundance standard, except for Mg, Si and S, which are slightly non-solar. The strong and broad ($\sim$300 km/s) disc-like emission displayed by the H$伪$ line suggests a centrifugal magnetosphere supported by the strong magnetic field. Our results imply that CPD-62 2124 is an early B-type star hosting one of the strongest magnetic fields discovered to date, and one of the most evolved He-strong stars known, with a fractional main-sequence lifetime of approximately 0.6. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.01537v1-abstract-full').style.display = 'none'; document.getElementById('1612.01537v1-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 December, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 597, L6 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.04502">arXiv:1611.04502</a> <span> [<a href="https://arxiv.org/pdf/1611.04502">pdf</a>, <a href="https://arxiv.org/ps/1611.04502">ps</a>, <a href="https://arxiv.org/format/1611.04502">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/10.1051/0004-6361/201628905">10.1051/0004-6361/201628905 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B fields in OB stars (BOB): Concluding the FORS2 observing campaign </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Schoeller%2C+M">M. Schoeller</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Carroll%2C+T+A">T. A. Carroll</a>, <a href="/search/astro-ph?searchtype=author&query=Briquet%2C+M">M. Briquet</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=Jarvinen%2C+S">S. Jarvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+F">M. F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Kholtygin%2C+A+F">A. F. Kholtygin</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Barba%2C+R+H">R. H. Barba</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=collaboration%2C+t+B">the BOB 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="1611.04502v1-abstract-short" style="display: inline;"> The "B fields in OB stars" (BOB) collaboration is based on an ESO Large Programme, to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. In the framework of this programme, we carried out low-resolution spectropolarimetric observations of a large sample of massive stars using FORS2 installed at the ESO VLT 8-m telescope. We determined the magn… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.04502v1-abstract-full').style.display = 'inline'; document.getElementById('1611.04502v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.04502v1-abstract-full" style="display: none;"> The "B fields in OB stars" (BOB) collaboration is based on an ESO Large Programme, to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. In the framework of this programme, we carried out low-resolution spectropolarimetric observations of a large sample of massive stars using FORS2 installed at the ESO VLT 8-m telescope. We determined the magnetic field values with two completely independent reduction and analysis pipelines. Our in-depth study of the magnetic field measurements shows that differences between our two pipelines are usually well within 3sigma errors. From the 32 observations of 28 OB stars, we were able to monitor the magnetic fields in CPD-57 3509 and HD164492C, confirm the magnetic field in HD54879, and detect a magnetic field in CPD-62 2124. We obtain a magnetic field detection rate of 6+-3% for the full sample of 69 OB stars observed with FORS2 within the BOB programme. For the pre-selected objects with a v sin i below 60 km/s, we obtain a magnetic field detection rate of 5+-5%. We also discuss X-ray properties and multiplicity of the objects in our FORS2 sample with respect to the magnetic field detections. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.04502v1-abstract-full').style.display = 'none'; document.getElementById('1611.04502v1-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 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 3 tables, 5 figures, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 599, A66 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.07873">arXiv:1609.07873</a> <span> [<a href="https://arxiv.org/pdf/1609.07873">pdf</a>, <a href="https://arxiv.org/format/1609.07873">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/10.1051/0004-6361/201629244">10.1051/0004-6361/201629244 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CRIRES-POP: a library of high resolution spectra from 1 to 5 microns II. Data reduction and the spectrum of the K giant 10 Leo </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nicholls%2C+C+P">C. P. Nicholls</a>, <a href="/search/astro-ph?searchtype=author&query=Lebzelter%2C+T">T. Lebzelter</a>, <a href="/search/astro-ph?searchtype=author&query=Smette%2C+A">A. Smette</a>, <a href="/search/astro-ph?searchtype=author&query=Wolff%2C+B">B. Wolff</a>, <a href="/search/astro-ph?searchtype=author&query=Hartman%2C+H">H. Hartman</a>, <a href="/search/astro-ph?searchtype=author&query=K%C3%A4ufl%2C+H+-">H. -U. K盲ufl</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Ramsay%2C+S">S. Ramsay</a>, <a href="/search/astro-ph?searchtype=author&query=Uttenthaler%2C+S">S. Uttenthaler</a>, <a href="/search/astro-ph?searchtype=author&query=Wahlgren%2C+G+M">G. M. Wahlgren</a>, <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">S. Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Hussain%2C+G+A+J">G. A. J. Hussain</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=Seeman%2C+U">U. Seeman</a>, <a href="/search/astro-ph?searchtype=author&query=Seifahrt%2C+A">A. Seifahrt</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="1609.07873v1-abstract-short" style="display: inline;"> Context. High resolution stellar spectral atlases are valuable resources to astronomy. They are rare in the $1 - 5\,渭$m region for historical reasons, but once available, high resolution atlases in this part of the spectrum will aid the study of a wide range of astrophysical phenomena. Aims. The aim of the CRIRES-POP project is to produce a high resolution near-infrared spectral library of stars a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07873v1-abstract-full').style.display = 'inline'; document.getElementById('1609.07873v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.07873v1-abstract-full" style="display: none;"> Context. High resolution stellar spectral atlases are valuable resources to astronomy. They are rare in the $1 - 5\,渭$m region for historical reasons, but once available, high resolution atlases in this part of the spectrum will aid the study of a wide range of astrophysical phenomena. Aims. The aim of the CRIRES-POP project is to produce a high resolution near-infrared spectral library of stars across the H-R diagram. The aim of this paper is to present the fully reduced spectrum of the K giant 10 Leo that will form the basis of the first atlas within the CRIRES-POP library, to provide a full description of the data reduction processes involved, and to provide an update on the CRIRES-POP project. Methods. All CRIRES-POP targets were observed with almost 200 different observational settings of CRIRES on the ESO Very Large Telescope, resulting in a basically complete coverage of its spectral range as accessible from the ground. We reduced the spectra of 10 Leo with the CRIRES pipeline, corrected the wavelength solution and removed telluric absorption with Molecfit, then resampled the spectra to a common wavelength scale, shifted them to rest wavelengths, flux normalised, and median combined them into one final data product. Results. We present the fully reduced, high resolution, near-infrared spectrum of 10 Leo. This is also the first complete spectrum from the CRIRES instrument. The spectrum is available online. Conclusions. The first CRIRES-POP spectrum has exceeded our quality expectations and will form the centre of a state-of-the-art stellar atlas. This first CRIRES-POP atlas will soon be available, and further atlases will follow. All CRIRES-POP data products will be freely and publicly available online. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07873v1-abstract-full').style.display = 'none'; document.getElementById('1609.07873v1-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 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 12 figures, accepted to A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 598, A79 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.01480">arXiv:1609.01480</a> <span> [<a href="https://arxiv.org/pdf/1609.01480">pdf</a>, <a href="https://arxiv.org/format/1609.01480">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/10.1117/12.2232483">10.1117/12.2232483 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SimCADO - an instrument data simulator package for MICADO at the E-ELT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Leschinski%2C+K">Kieran Leschinski</a>, <a href="/search/astro-ph?searchtype=author&query=Czoske%2C+O">Oliver Czoske</a>, <a href="/search/astro-ph?searchtype=author&query=K%C3%B6hler%2C+R">Rainer K枚hler</a>, <a href="/search/astro-ph?searchtype=author&query=Mach%2C+M">Michael Mach</a>, <a href="/search/astro-ph?searchtype=author&query=Zeilinger%2C+W">Werner Zeilinger</a>, <a href="/search/astro-ph?searchtype=author&query=Kleijn%2C+G+V">Gijs Verdoes Kleijn</a>, <a href="/search/astro-ph?searchtype=author&query=Alves%2C+J">Joao Alves</a>, <a href="/search/astro-ph?searchtype=author&query=Kausch%2C+W">Wolfgang Kausch</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</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="1609.01480v1-abstract-short" style="display: inline;"> MICADO will be the first-light wide-field imager for the European Extremely Large Telescope (E-ELT) and will provide difiraction limited imaging (7mas at 1.2mm) over a ~53 arcsecond field of view. In order to support various consortium activities we have developed a first version of SimCADO: an instrument simulator for MICADO. SimCADO uses the results of the detailed simulation efforts conducted f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.01480v1-abstract-full').style.display = 'inline'; document.getElementById('1609.01480v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.01480v1-abstract-full" style="display: none;"> MICADO will be the first-light wide-field imager for the European Extremely Large Telescope (E-ELT) and will provide difiraction limited imaging (7mas at 1.2mm) over a ~53 arcsecond field of view. In order to support various consortium activities we have developed a first version of SimCADO: an instrument simulator for MICADO. SimCADO uses the results of the detailed simulation efforts conducted for each of the separate consortium-internal work packages in order to generate a model of the optical path from source to detector readout. SimCADO is thus a tool to provide scientific context to both the science and instrument development teams who are ultimately responsible for the final design and future capabilities of the MICADO instrument. Here we present an overview of the inner workings of SimCADO and outline our plan for its further development. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.01480v1-abstract-full').style.display = 'none'; document.getElementById('1609.01480v1-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 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">to appear in Ground-based and Airborne Instrumentation for Astronomy VI, eds. Evans C., Simard L., Takami H., Proc. SPIE vol. 9908 id 73; 2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.04325">arXiv:1607.04325</a> <span> [<a href="https://arxiv.org/pdf/1607.04325">pdf</a>, <a href="https://arxiv.org/format/1607.04325">other</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 class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-637X/829/2/70">10.3847/0004-637X/829/2/70 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A spectroscopic study of blue supergiant stars in the Sculptor galaxy NGC 55: chemical evolution and distance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R">Rolf Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M">Miguel Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">Norberto Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Ho%2C+I">I-Ting Ho</a>, <a href="/search/astro-ph?searchtype=author&query=Bresolin%2C+F">Fabio Bresolin</a>, <a href="/search/astro-ph?searchtype=author&query=Gieren%2C+W">Wolfgang Gieren</a>, <a href="/search/astro-ph?searchtype=author&query=Pietrzynski%2C+G">Grzegorz Pietrzynski</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">Norbert Przybilla</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1607.04325v1-abstract-short" style="display: inline;"> Low resolution (4.5 to 5 Angstroem) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities and metallicities (from iron peak and alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_25 is detected. The central metallicity on a loga… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.04325v1-abstract-full').style.display = 'inline'; document.getElementById('1607.04325v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.04325v1-abstract-full" style="display: none;"> Low resolution (4.5 to 5 Angstroem) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities and metallicities (from iron peak and alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_25 is detected. The central metallicity on a logarithmic scale relative to the Sun is [Z] = -0.37 +\- 0.03. A chemical evolution model using the observed distribution of stellar and interstellar medium gas mass column densities reproduces the observed metallicity distribution well and reveals a recent history of strong galactic mass accretion and wind outflows with accretion and mass-loss rates of the order of the star formation rate. There is an indication of spatial inhomogeneity in metallicity. In addition, the relatively high central metallicity of the disk confirms that two extra-planar metal poor HII regions detected in previous work 1.13 to 2.22 kpc above the galactic plane are ionized by massive stars formed in-situ outside the disk. For a sub-sample of supergiants, for which Hubble Space Telescope photometry is available, the flux-weighted gravity--luminosity relationship is used to determine a distance modulus of 26.85 +\- 0.10 mag. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.04325v1-abstract-full').style.display = 'none'; document.getElementById('1607.04325v1-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 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by ApJ, 29 pages, 13 figures, 4 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.01954">arXiv:1607.01954</a> <span> [<a href="https://arxiv.org/pdf/1607.01954">pdf</a>, <a href="https://arxiv.org/ps/1607.01954">ps</a>, <a href="https://arxiv.org/format/1607.01954">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/10.1117/12.2233047">10.1117/12.2233047 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> MICADO: first light imager for the E-ELT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Davies%2C+R">R. Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Schubert%2C+J">J. Schubert</a>, <a href="/search/astro-ph?searchtype=author&query=Hartl%2C+M">M. Hartl</a>, <a href="/search/astro-ph?searchtype=author&query=Alves%2C+J">J. Alves</a>, <a href="/search/astro-ph?searchtype=author&query=Cl%C3%A9net%2C+Y">Y. Cl茅net</a>, <a href="/search/astro-ph?searchtype=author&query=Lang-Bardl%2C+F">F. Lang-Bardl</a>, <a href="/search/astro-ph?searchtype=author&query=Nicklas%2C+H">H. Nicklas</a>, <a href="/search/astro-ph?searchtype=author&query=Pott%2C+J+-">J. -U. Pott</a>, <a href="/search/astro-ph?searchtype=author&query=Ragazzoni%2C+R">R. Ragazzoni</a>, <a href="/search/astro-ph?searchtype=author&query=Tolstoy%2C+E">E. Tolstoy</a>, <a href="/search/astro-ph?searchtype=author&query=Agocs%2C+T">T. Agocs</a>, <a href="/search/astro-ph?searchtype=author&query=Anwand-Heerwart%2C+H">H. Anwand-Heerwart</a>, <a href="/search/astro-ph?searchtype=author&query=Barboza%2C+S">S. Barboza</a>, <a href="/search/astro-ph?searchtype=author&query=Baudoz%2C+P">P. Baudoz</a>, <a href="/search/astro-ph?searchtype=author&query=Bender%2C+R">R. Bender</a>, <a href="/search/astro-ph?searchtype=author&query=Bizenberger%2C+P">P. Bizenberger</a>, <a href="/search/astro-ph?searchtype=author&query=Boccaletti%2C+A">A. Boccaletti</a>, <a href="/search/astro-ph?searchtype=author&query=Boland%2C+W">W. Boland</a>, <a href="/search/astro-ph?searchtype=author&query=Bonifacio%2C+P">P. Bonifacio</a>, <a href="/search/astro-ph?searchtype=author&query=Briegel%2C+F">F. Briegel</a>, <a href="/search/astro-ph?searchtype=author&query=Buey%2C+T">T. Buey</a>, <a href="/search/astro-ph?searchtype=author&query=Chapron%2C+F">F. Chapron</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+M">M. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Czoske%2C+O">O. Czoske</a>, <a href="/search/astro-ph?searchtype=author&query=Dreizler%2C+S">S. Dreizler</a> , et al. (59 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1607.01954v1-abstract-short" style="display: inline;"> MICADO will equip the E-ELT with a first light capability for diffraction limited imaging at near-infrared wavelengths. The instrument's observing modes focus on various flavours of imaging, including astrometric, high contrast, and time resolved. There is also a single object spectroscopic mode optimised for wavelength coverage at moderately high resolution. This contribution provides an overview… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.01954v1-abstract-full').style.display = 'inline'; document.getElementById('1607.01954v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.01954v1-abstract-full" style="display: none;"> MICADO will equip the E-ELT with a first light capability for diffraction limited imaging at near-infrared wavelengths. The instrument's observing modes focus on various flavours of imaging, including astrometric, high contrast, and time resolved. There is also a single object spectroscopic mode optimised for wavelength coverage at moderately high resolution. This contribution provides an overview of the key functionality of the instrument, outlining the scientific rationale for its observing modes. The interface between MICADO and the adaptive optics system MAORY that feeds it is summarised. The design of the instrument is discussed, focussing on the optics and mechanisms inside the cryostat, together with a brief overview of the other key sub-systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.01954v1-abstract-full').style.display = 'none'; document.getElementById('1607.01954v1-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 July, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">to appear in Ground-based and Airborne Instrumentation for Astronomy VI, eds. Evans C., Simard L., Takami H., Proc. SPIE vol. 9908 id 73; 2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1601.02268">arXiv:1601.02268</a> <span> [<a href="https://arxiv.org/pdf/1601.02268">pdf</a>, <a href="https://arxiv.org/ps/1601.02268">ps</a>, <a href="https://arxiv.org/format/1601.02268">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/10.1051/0004-6361/201527646">10.1051/0004-6361/201527646 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD-57掳 3509 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Nieva%2C+M+-">M. -F. Nieva</a>, <a href="/search/astro-ph?searchtype=author&query=J%C3%A4rvinen%2C+S+P">S. P. J盲rvinen</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%B6ller%2C+M">M. Sch枚ller</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Butler%2C+K">K. Butler</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">F. R. N. Schneider</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=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</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=collaboration%2C+t+B">the BOB 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="1601.02268v1-abstract-short" style="display: inline;"> We report the detection of a magnetic field in the helium-strong star CPD-57 3509 (B2 IV), a member of the Galactic open cluster NGC3293, and characterise the star's atmospheric and fundamental parameters. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed usi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.02268v1-abstract-full').style.display = 'inline'; document.getElementById('1601.02268v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1601.02268v1-abstract-full" style="display: none;"> We report the detection of a magnetic field in the helium-strong star CPD-57 3509 (B2 IV), a member of the Galactic open cluster NGC3293, and characterise the star's atmospheric and fundamental parameters. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD-57 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in H伪 is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23750+-250 K and 4.05+-0.10, respectively, and a surface helium fraction of 0.28+-0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD-57 3509 is one of the most evolved He-strong stars known. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1601.02268v1-abstract-full').style.display = 'none'; document.getElementById('1601.02268v1-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 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 11 figures. Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 587, A7 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.06314">arXiv:1510.06314</a> <span> [<a href="https://arxiv.org/pdf/1510.06314">pdf</a>, <a href="https://arxiv.org/ps/1510.06314">ps</a>, <a href="https://arxiv.org/format/1510.06314">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/10.1051/0004-6361/201527300">10.1051/0004-6361/201527300 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the neutron-capture elements across the Galactic thin disk using Cepheids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=da+Silva%2C+R">R. da Silva</a>, <a href="/search/astro-ph?searchtype=author&query=Lemasle%2C+B">B. Lemasle</a>, <a href="/search/astro-ph?searchtype=author&query=Bono%2C+G">G. Bono</a>, <a href="/search/astro-ph?searchtype=author&query=Genovali%2C+K">K. Genovali</a>, <a href="/search/astro-ph?searchtype=author&query=McWilliam%2C+A">A. McWilliam</a>, <a href="/search/astro-ph?searchtype=author&query=Cristallo%2C+S">S. Cristallo</a>, <a href="/search/astro-ph?searchtype=author&query=Bergemann%2C+M">M. Bergemann</a>, <a href="/search/astro-ph?searchtype=author&query=Buonanno%2C+R">R. Buonanno</a>, <a href="/search/astro-ph?searchtype=author&query=Fabrizio%2C+M">M. Fabrizio</a>, <a href="/search/astro-ph?searchtype=author&query=Ferraro%2C+I">I. Ferraro</a>, <a href="/search/astro-ph?searchtype=author&query=Francois%2C+P">P. Francois</a>, <a href="/search/astro-ph?searchtype=author&query=Iannicola%2C+G">G. Iannicola</a>, <a href="/search/astro-ph?searchtype=author&query=Inno%2C+L">L. Inno</a>, <a href="/search/astro-ph?searchtype=author&query=Laney%2C+C+D">C. D. Laney</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R+-">R. -P. Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Matsunaga%2C+N">N. Matsunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Nonino%2C+M">M. Nonino</a>, <a href="/search/astro-ph?searchtype=author&query=Primas%2C+F">F. Primas</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Romaniello%2C+M">M. Romaniello</a>, <a href="/search/astro-ph?searchtype=author&query=Thevenin%2C+F">F. Thevenin</a>, <a href="/search/astro-ph?searchtype=author&query=Urbaneja%2C+M+A">M. A. Urbaneja</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="1510.06314v1-abstract-short" style="display: inline;"> We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R ~ 38,000) and high signal-to-noise ratio (S/N ~ 50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.06314v1-abstract-full').style.display = 'inline'; document.getElementById('1510.06314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.06314v1-abstract-full" style="display: none;"> We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R ~ 38,000) and high signal-to-noise ratio (S/N ~ 50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either by our group (111 stars) or available in the literature, we end up with a sample of 435 Cepheids covering a broad range in iron abundances (-1.6 < [Fe/H] < 0.6). We found, using homogeneous individual distances and abundance scales, well defined gradients for the above elements. However, the slope of the light s-process element (Y) is at least a factor of two steeper than the slopes of heavy s- (La, Ce, Nd) and r- (Eu) process elements. The s to r abundance ratio ([La/Eu]) of Cepheids shows a well defined anticorrelation with of both Eu and Fe. On the other hand, Galactic field stars attain an almost constant value and only when they approach solar iron abundance display a mild enhancement in La. The [Y/Eu] ratio shows a mild evidence of a correlation with Eu and, in particular, with iron abundance for field Galactic stars. We also investigated the s-process index - [hs/ls] - and we found a well defined anticorrelation, as expected, between [La/Y] and iron abundance. Moreover, we found a strong correlation between [La/Y] and [La/Fe] and, in particular, a clear separation between Galactic and Sagittarius red giants. Finally, the comparison between predictions for low-mass asymptotic giant branch stars and the observed [La/Y] ratio indicate a very good agreement over the entire metallicity range covered by Cepheids. However, the observed spread, at fixed iron content, is larger than predicted by current models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.06314v1-abstract-full').style.display = 'none'; document.getElementById('1510.06314v1-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 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">30 pages, 12 figures, 7 tables. Accepted for publication in the Astronomy and Astrophysics journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 586, A125 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1508.00750">arXiv:1508.00750</a> <span> [<a href="https://arxiv.org/pdf/1508.00750">pdf</a>, <a href="https://arxiv.org/ps/1508.00750">ps</a>, <a href="https://arxiv.org/format/1508.00750">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/10.1051/0004-6361/201526725">10.1051/0004-6361/201526725 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B fields in OB stars (BOB): low-resolution FORS2 spectropolarimetry of the first sample of 50 massive stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Schoeller%2C+M">M. Schoeller</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Briquet%2C+M">M. Briquet</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">F. R. N. Schneider</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=collaboration%2C+t+B">the BOB 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="1508.00750v1-abstract-short" style="display: inline;"> Within the context of the collaboration "B fields in OB stars (BOB)", we used the FORS2 low-resolution spectropolarimeter to search for a magnetic field in 50 massive stars, including two reference magnetic massive stars. Because of the many controversies of magnetic field detections obtained with the FORS instruments, we derived the magnetic field values with two completely independent reduction… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.00750v1-abstract-full').style.display = 'inline'; document.getElementById('1508.00750v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1508.00750v1-abstract-full" style="display: none;"> Within the context of the collaboration "B fields in OB stars (BOB)", we used the FORS2 low-resolution spectropolarimeter to search for a magnetic field in 50 massive stars, including two reference magnetic massive stars. Because of the many controversies of magnetic field detections obtained with the FORS instruments, we derived the magnetic field values with two completely independent reduction and analysis pipelines. We compare and discuss the results obtained from the two pipelines. We obtained a general good agreement, indicating that most of the discrepancies on magnetic field detections reported in the literature are caused by the interpretation of the significance of the results (i.e., 3-4 sigma detections considered as genuine, or not), instead of by significant differences in the derived magnetic field values. By combining our results with past FORS1 measurements of HD46328, we improve the estimate of the stellar rotation period, obtaining P = 2.17950+/-0.00009 days. For HD125823, our FORS2 measurements do not fit the available magnetic field model, based on magnetic field values obtained 30 years ago. We repeatedly detect a magnetic field for the O9.7V star HD54879, the HD164492C massive binary, and the He-rich star CPD -57 3509. We obtain a magnetic field detection rate of 6+/-4%, while by considering only the apparently slow rotators we derive a detection rate of 8+/-5%, both comparable with what was previously reported by other similar surveys. We are left with the intriguing result that, although the large majority of magnetic massive stars is rotating slowly, our detection rate is not a strong function of the stellar rotational velocity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1508.00750v1-abstract-full').style.display = 'none'; document.getElementById('1508.00750v1-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> 4 August, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">20 pages, 10 figures, 4 tables; accepted for publication on Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 582, A45 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.03591">arXiv:1507.03591</a> <span> [<a href="https://arxiv.org/pdf/1507.03591">pdf</a>, <a href="https://arxiv.org/format/1507.03591">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/10.1051/0004-6361/201425354">10.1051/0004-6361/201425354 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> B fields in OB stars (BOB): Detection of a strong magnetic field in the O9.7 V star HD54879 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Hubrig%2C+S">S. Hubrig</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=Sch%C3%B6ller%2C+M">M. Sch枚ller</a>, <a href="/search/astro-ph?searchtype=author&query=Ilyin%2C+I">I. Ilyin</a>, <a href="/search/astro-ph?searchtype=author&query=Carrol%2C+T+A">T. A. Carrol</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Morel%2C+T">T. Morel</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">F. R. N. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Przybilla%2C+N">N. Przybilla</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=Oskinova%2C+L+M">L. M. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Reisenegger%2C+A">A. Reisenegger</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+t+B">the BOB 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="1507.03591v1-abstract-short" style="display: inline;"> The number of magnetic stars detected among massive stars is small; nevertheless, the role played by the magnetic field in stellar evolution cannot be disregarded. Links between line profile variability, enhancements/depletions of surface chemical abundances, and magnetic fields have been identified for low-mass B-stars, but for the O-type domain this is almost unexplored. Based on FORS2 and HARPS… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.03591v1-abstract-full').style.display = 'inline'; document.getElementById('1507.03591v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.03591v1-abstract-full" style="display: none;"> The number of magnetic stars detected among massive stars is small; nevertheless, the role played by the magnetic field in stellar evolution cannot be disregarded. Links between line profile variability, enhancements/depletions of surface chemical abundances, and magnetic fields have been identified for low-mass B-stars, but for the O-type domain this is almost unexplored. Based on FORS2 and HARPS spectropolarimetric data, we present the first detection of a magnetic field in HD54879, a single slowly rotating O9.7 V star. Using two independent and different techniques we obtained the firm detection of a surface average longitudinal magnetic field with a maximum amplitude of about 600 G, in modulus. A quantitative spectroscopic analysis of the star with the stellar atmosphere code FASTWIND results in an effective temperature and a surface gravity of 33000$\pm1000$ K and 4.0$\pm0.1$ dex. The abundances of carbon, nitrogen, oxygen, silicon, and magnesium are found to be slightly lower than solar, but compatible within the errors. We investigate line-profile variability in HD54879 by complementing our spectra with spectroscopic data from other recent OB-star surveys. The photospheric lines remain constant in shape between 2009 and 2014, although H$伪$ shows a variable emission. The H$伪$ emission is too strong for a standard O9.7 V and is probably linked to the magnetic field and the presence of circumstellar material. Its normal chemical composition and the absence of photospheric line profile variations make HD54879 the most strongly magnetic, non-variable single O-star detected to date. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.03591v1-abstract-full').style.display = 'none'; document.getElementById('1507.03591v1-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 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">16 pages, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 581, A81 (2015) </p> </li> </ol> <nav class="pagination 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