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<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=Puls%2C+J&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Puls%2C+J&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Puls%2C+J&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Puls%2C+J&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/2411.06884">arXiv:2411.06884</a> <span> [<a href="https://arxiv.org/pdf/2411.06884">pdf</a>, <a href="https://arxiv.org/format/2411.06884">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive stars at low metallicity VI. Atmosphere and mass-loss properties of O-type giants in the Small Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Backs%2C+F">Frank Backs</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</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=Kaper%2C+L">L. Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">J. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Tramper%2C+F">F. Tramper</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Bernini-Peron%2C+M">M. Bernini-Peron</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">C. Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Ignace%2C+R">R. Ignace</a>, <a href="/search/astro-ph?searchtype=author&query=Kuiper%2C+R">R. Kuiper</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=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Marcolino%2C+W">W. Marcolino</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</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=Pauli%2C+D">D. Pauli</a>, <a href="/search/astro-ph?searchtype=author&query=Ramachandran%2C+V">V. Ramachandran</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Verhamme%2C+O">O. Verhamme</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="2411.06884v1-abstract-short" style="display: inline;"> Mass loss through a stellar wind is an important physical process that steers the evolution of massive stars and controls the properties of their end-of-life products, such as the supernova type and the mass of compact remnants. For an accurate mass loss determination, the inhomogeneities in the wind, known as clumping, needs to be taking into account. We aim to improve empirical estimates of mass… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06884v1-abstract-full').style.display = 'inline'; document.getElementById('2411.06884v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.06884v1-abstract-full" style="display: none;"> Mass loss through a stellar wind is an important physical process that steers the evolution of massive stars and controls the properties of their end-of-life products, such as the supernova type and the mass of compact remnants. For an accurate mass loss determination, the inhomogeneities in the wind, known as clumping, needs to be taking into account. We aim to improve empirical estimates of mass loss and wind clumping for hot main-sequence massive stars, study the dependence of both properties on the metallicity, and compare the theoretical predictions to our findings. We analyzed the optical and UV spectra of 13 O-type stars in the Small Magellanic Cloud galaxy, which has a metallicity of $\sim 0.2\,Z_\odot$. We quantified the stellar atmosphere, outflow, and wind-clumping properties. To probe the role of metallicity, we compared our findings to studies of Galactic and Large Magellanic Cloud samples that were analyzed with similar methods. We find significant variations in the wind-clumping properties of the target stars, with clumping starting at flow velocities $0.01 - 0.23$ of the terminal wind velocity and reaching clumping factors $f_{\rm cl} = 2 - 30$. In the luminosity ($\log L / L_{\odot} = 5.0 - 6.0$) and metallicity ($Z/Z_{\odot} = 0.2 - 1$) range we considered, we find that the scaling of the mass loss $\dot{M}$ with metallicity $Z$ varies with luminosity. At $\log L/L_{\odot} = 5.75$, we find $\dot{M} \propto Z^m$ with $m = 1.02 \pm 0.30$, in agreement with pioneering work in the field. For lower luminosities, however, we obtain a significantly steeper scaling of $m > 2$. The monotonically decreasing $m(L)$ behavior adds a complexity to the functional description of the mass-loss rate of hot massive stars. Although the trend is present in the predictions, it is much weaker than we found here. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06884v1-abstract-full').style.display = 'none'; document.getElementById('2411.06884v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">37 pages, 29 figures. Accepted for publication in Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.14937">arXiv:2410.14937</a> <span> [<a href="https://arxiv.org/pdf/2410.14937">pdf</a>, <a href="https://arxiv.org/format/2410.14937">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/10.1051/0004-6361/202451169">10.1051/0004-6361/202451169 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive Stars at low metallicity IX: Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Verhamme%2C+O">O. Verhamme</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">J. Sundqvist</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=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Backs%2C+F">F. Backs</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Kub%C3%A1tov%C3%A1%2C+B">B. Kub谩tov谩</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Bernini-Peron%2C+M">M. Bernini-Peron</a>, <a href="/search/astro-ph?searchtype=author&query=Kuiper%2C+R">R. Kuiper</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R+K">R. K. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Schillemans%2C+P">P. Schillemans</a>, <a href="/search/astro-ph?searchtype=author&query=Shenar%2C+T">T. Shenar</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=collaboration%2C+X">XShootu collaboration</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.14937v2-abstract-short" style="display: inline;"> Context. Current implementations of mass loss for hot, massive stars in stellar evolution models include a sharp increase in mass loss when blue supergiants become cooler than Teff 20-22kK. This drastic mass-loss jump has been motivated by the potential presence of a so-called bistability ionisation effect, which may occur for line-driven winds in this temperature region due to recombination of im… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14937v2-abstract-full').style.display = 'inline'; document.getElementById('2410.14937v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.14937v2-abstract-full" style="display: none;"> Context. Current implementations of mass loss for hot, massive stars in stellar evolution models include a sharp increase in mass loss when blue supergiants become cooler than Teff 20-22kK. This drastic mass-loss jump has been motivated by the potential presence of a so-called bistability ionisation effect, which may occur for line-driven winds in this temperature region due to recombination of important line-driving ions. Aims. We perform quantitative spectroscopy using UV (ULLYSES program) and optical (XShootU collaboration) data for 17 OB-supergiant stars in the LMC (covering the range Teff 14-32kK), deriving absolute constraints on global stellar, wind, and clumping parameters. We examine whether there are any empirical signs of a mass-loss jump in the investigated region, and we study the clumped nature of the wind. Methods. We use a combination of the model atmosphere code fastwind and the genetic algorithm code Kiwi-GA to fit synthetic spectra of a multitude of diagnostic spectral lines in the optical and UV. Results. We find no signs of any upward mass loss jump anywhere in the examined region. Standard theoretical comparison models, which include a strong bistability jump thus severely over predict the empirical mass-loss rates on the cool side of the predicted jump. Additionally, we find that on average about 40% of the total wind mass seems to reside in the diluted medium in between dense clumps. Conclusions. Our derived mass-loss rates suggest that for applications like stellar evolution one should not include a drastic bistability jump in mass loss for stars in the temperature and luminosity region investigated here. The derived high values of interclump density further suggest that the common assumption of an effectively void interclump medium (applied in the vast majority of spectroscopic studies of hot star winds) is not generally valid in this parameter regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14937v2-abstract-full').style.display = 'none'; document.getElementById('2410.14937v2-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 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">Journal ref:</span> A&A 692, A91 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.03329">arXiv:2409.03329</a> <span> [<a href="https://arxiv.org/pdf/2409.03329">pdf</a>, <a href="https://arxiv.org/format/2409.03329">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="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> Stellar Atmospheres </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">Artemio Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Prieto%2C+C+A">Carlos Allende Prieto</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="2409.03329v1-abstract-short" style="display: inline;"> Stars play a decisive role in our Universe, from its beginning throughout its complete evolution. For a thorough understanding of their properties, evolution, and physics of their outer envelopes, stellar spectra need to be analyzed by comparison with numerical models of their atmospheres. We discuss the foundations of how to calculate such models (in particular, density and temperature stratifica… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03329v1-abstract-full').style.display = 'inline'; document.getElementById('2409.03329v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03329v1-abstract-full" style="display: none;"> Stars play a decisive role in our Universe, from its beginning throughout its complete evolution. For a thorough understanding of their properties, evolution, and physics of their outer envelopes, stellar spectra need to be analyzed by comparison with numerical models of their atmospheres. We discuss the foundations of how to calculate such models (in particular, density and temperature stratification, affected by convective energy transport in low-mass stars), which requires a parallel treatment of hydrodynamics, thermodynamics and radiative transfer. We stress the impact of emissivities, opacities, and particularly their ratio (source function), and summarize how these quantities are calculated, either adopting or relaxing the assumption of LTE (local thermodynamic equilibrium). Subsequently, we discuss the influence and physics of stellar winds (and their various driving mechanisms as a function of stellar type), rotation, magnetic fields, inhomogeneities, and multiplicity. Finally, we outline the basics of quantitative spectroscopy, namely how to analyze observed spectra in practice. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03329v1-abstract-full').style.display = 'none'; document.getElementById('2409.03329v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">This is a pre-print of a chapter for the Encyclopedia of Astrophysics (edited by I. Mandel, section editor F.R.N. Schneider) to be published by Elsevier as a Reference Module</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.11713">arXiv:2408.11713</a> <span> [<a href="https://arxiv.org/pdf/2408.11713">pdf</a>, <a href="https://arxiv.org/format/2408.11713">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Properties of intermediate- to high-mass stars in the young cluster M17 -- Characterizing the (pre-)zero-age main sequence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Backs%2C+F">Frank Backs</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Ram%C3%ADrez-Tannus%2C+M+C">M. C. Ram铆rez-Tannus</a>, <a href="/search/astro-ph?searchtype=author&query=Derkink%2C+A+R">A. R. Derkink</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=Poorta%2C+J">J. Poorta</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">Lex Kaper</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.11713v1-abstract-short" style="display: inline;"> The outcome of the formation of massive stars is an important anchor point in their evolution. It provides insight into the physics of the assembly process, and sets the conditions for stellar evolution. We characterize a population of 18 highly reddened O4.5 to B9 stars in the very young massive star-forming region M17. Their properties allow us to identify the empirical location of the ZAMS, and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11713v1-abstract-full').style.display = 'inline'; document.getElementById('2408.11713v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.11713v1-abstract-full" style="display: none;"> The outcome of the formation of massive stars is an important anchor point in their evolution. It provides insight into the physics of the assembly process, and sets the conditions for stellar evolution. We characterize a population of 18 highly reddened O4.5 to B9 stars in the very young massive star-forming region M17. Their properties allow us to identify the empirical location of the ZAMS, and rotation and mass-loss rate of stars there. We performed quantitative spectroscopic modeling of VLT/X-shooter spectra using NLTE atmosphere code Fastwind and fitting approach Kiwi-GA. The observed SEDs were used to determine the line-of-sight extinction. From a comparison of their positions in the HRD with MIST evolutionary tracks, we inferred the stellar masses and ages. We find an age of $0.4_{-0.2}^{+0.6}$ Myr for our sample, however we also identify a strong relation between the age and the mass of the stars. The extinction towards the sources ranges from $A_V = 3.6$ to 10.6. Stars more massive than 10 M$_{\odot}$ have reached the ZAMS. Their projected ZAMS spin rate distribution extends to 0.3 of the critical velocity; their mass-loss rates agree with those of other main-sequence OB stars. Stars with a mass in the range $3 < M/$M$_{\odot} < 7$ are still on the pre-main sequence (PMS). Evolving their $v \sin i$ to the ZAMS yields values up to $\sim 0.6 v_{\rm crit}$. For PMS stars without disks, we find tentative mass-loss rates up to $10^{-8.5}\,$M$_{\odot}$\,yr$^{-1}$. We constrain the empirical location of the ZAMS for massive ($10 < M/$M$_{\odot} < 50$) stars. The ZAMS rotation rates for intermediate-mass stars are twice as high as for massive stars, suggesting that the angular momentum gain processes differ between the two groups. The relation between the age and mass of the stars suggests a lag in the formation of more massive stars relative to lower mass stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11713v1-abstract-full').style.display = 'none'; document.getElementById('2408.11713v1-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 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">37 pages, 31 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/2407.20492">arXiv:2407.20492</a> <span> [<a href="https://arxiv.org/pdf/2407.20492">pdf</a>, <a href="https://arxiv.org/format/2407.20492">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> The effects of surface fossil magnetic fields on massive star evolution: V. Models at low metallicity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Z. Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Chiaki%2C+G">G. Chiaki</a>, <a href="/search/astro-ph?searchtype=author&query=Nagakura%2C+H">H. Nagakura</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a>, <a href="/search/astro-ph?searchtype=author&query=Takiwaki%2C+T">T. Takiwaki</a>, <a href="/search/astro-ph?searchtype=author&query=Tominaga%2C+N">N. Tominaga</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="2407.20492v1-abstract-short" style="display: inline;"> At metallicities lower than that of the Small Magellanic Cloud, it remains essentially unexplored how fossil magnetic fields, forming large-scale magnetospheres, could affect the evolution of massive stars, thereby impacting the fundamental building blocks of the early Universe. We extend our stellar evolution model grid with representative calculations of main-sequence, single-star models with in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20492v1-abstract-full').style.display = 'inline'; document.getElementById('2407.20492v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.20492v1-abstract-full" style="display: none;"> At metallicities lower than that of the Small Magellanic Cloud, it remains essentially unexplored how fossil magnetic fields, forming large-scale magnetospheres, could affect the evolution of massive stars, thereby impacting the fundamental building blocks of the early Universe. We extend our stellar evolution model grid with representative calculations of main-sequence, single-star models with initial masses of 20 and 60 M$_\odot$, including appropriate changes for low-metallicity environments ($Z = 10^{-3}-10^{-6}$). We scrutinise the magnetic, rotational, and chemical properties of the models. When lowering the metallicity, the rotational velocities can become higher and the tendency towards quasi-chemically homogeneous evolution increases. While magnetic fields aim to prevent the development of this evolutionary channel, the weakening stellar winds lead to less efficient magnetic braking in our models. Since the stellar radius is almost constant during a blueward evolution caused by efficient chemical mixing, the surface magnetic field strength remains unchanged in some models. We find core masses at the terminal-age main sequence between 22 and 52 M$_\odot$ for initially 60 M$_\odot$ models. This large difference is due to the vastly different chemical and rotational evolution. We conclude that in order to explain chemical species and, in particular, high nitrogen abundances in the early Universe, the adopted stellar models need to be under scrutiny. The assumptions regarding wind physics, chemical mixing, and magnetic fields will strongly impact the model predictions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20492v1-abstract-full').style.display = 'none'; document.getElementById('2407.20492v1-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 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">Accepted for publication in MNRAS. A full Reproduction Package is available</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.06775">arXiv:2407.06775</a> <span> [<a href="https://arxiv.org/pdf/2407.06775">pdf</a>, <a href="https://arxiv.org/format/2407.06775">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/10.1051/0004-6361/202348478">10.1051/0004-6361/202348478 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Empirical mass-loss rates and clumping properties of O-type stars in the LMC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">C. Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">M. Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Decin%2C+L">L. Decin</a>, <a href="/search/astro-ph?searchtype=author&query=deKoter%2C+A">A. deKoter</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</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="2407.06775v1-abstract-short" style="display: inline;"> We constrain wind parameters of a sample of 18 O-type stars in the LMC, through analysis with stellar atmosphere and wind models including the effects of optically thick clumping. This allows us to determine the most accurate spectroscopic mass-loss and wind structure properties of massive stars at sub-solar metallicity to date and gain insight into the impact of metallicity on massive stellar win… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06775v1-abstract-full').style.display = 'inline'; document.getElementById('2407.06775v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.06775v1-abstract-full" style="display: none;"> We constrain wind parameters of a sample of 18 O-type stars in the LMC, through analysis with stellar atmosphere and wind models including the effects of optically thick clumping. This allows us to determine the most accurate spectroscopic mass-loss and wind structure properties of massive stars at sub-solar metallicity to date and gain insight into the impact of metallicity on massive stellar winds. Combining high signal to noise (S/N) ratio spectroscopy in the UV and optical gives us access to diagnostics of multiple different physical processes in the stellar wind. We produce synthetic spectra using the stellar atmosphere modelling code FASTWIND, and reproduce the observed spectra using a genetic algorithm based fitting technique. We empirically constrain 15 physical parameters associated with the stellar and wind properties, including temperature, surface gravity, surface abundances, rotation, macroturbulence and wind parameters. We find, on average, mass-loss rates a factor of 4-5 lower than those predicted by Vink et al. 2001, in good agreement with predictions from Bjorklund et al. 2021, and the best agreement with those from Krticka et al. 2018. In the 'weak-wind' regime we find mass-loss rates orders of magnitude below any theoretical predictions. We find a positive correlation of clumping factors (fcl) with effective temperature with an average fcl = 14 +- 8 for the full sample. Above 38 kK an average 46 +- 24% of the wind velocity span is covered by clumps and the interclump density is 10-30% of the mean wind. Below an effective temperature of roughly 38 kK there must be additional light leakage for supergiants. For dwarf stars at low temperatures there is a statistical preference for very low clump velocity spans, however it is unclear if this can be physically motivated as there are no clearly observable wind signatures in UV diagnostics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06775v1-abstract-full').style.display = 'none'; document.getElementById('2407.06775v1-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 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">12 pages with 6 figures, plus 16 pages and 18 figures in appendix. 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 690, A126 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.03137">arXiv:2407.03137</a> <span> [<a href="https://arxiv.org/pdf/2407.03137">pdf</a>, <a href="https://arxiv.org/format/2407.03137">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/10.1051/0004-6361/202449829">10.1051/0004-6361/202449829 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive stars at low metallicity. IV. Spectral analysis methods and exemplary results for O stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Bernini-Peron%2C+M">M. Bernini-Peron</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Backs%2C+F">F. Backs</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=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Maryeva%2C+O">O. Maryeva</a>, <a href="/search/astro-ph?searchtype=author&query=Pauli%2C+D">D. Pauli</a>, <a href="/search/astro-ph?searchtype=author&query=Ramachandran%2C+V">V. Ramachandran</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez-Gonz%C3%A1lez%2C+V+M+A">V. M. A. G贸mez-Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Gormaz-Matamala%2C+A+C">A. C. Gormaz-Matamala</a>, <a href="/search/astro-ph?searchtype=author&query=Hamann%2C+W+-">W. -R. Hamann</a>, <a href="/search/astro-ph?searchtype=author&query=Hillier%2C+D+J">D. J. Hillier</a>, <a href="/search/astro-ph?searchtype=author&query=Kuiper%2C+R">R. Kuiper</a>, <a href="/search/astro-ph?searchtype=author&query=Larkin%2C+C+J+K">C. J. K. Larkin</a>, <a href="/search/astro-ph?searchtype=author&query=Lefever%2C+R+R">R. R. Lefever</a>, <a href="/search/astro-ph?searchtype=author&query=Mehner%2C+A">A. Mehner</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</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=Sch%C3%B6sser%2C+E+C">E. C. Sch枚sser</a> , et al. (4 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="2407.03137v2-abstract-short" style="display: inline;"> CONTEXT: The spectral analysis of hot, massive stars is a fundamental astrophysical method to obtain their intrinsic properties and their feedback. Quantitative spectroscopy for hot, massive stars requires detailed numerical modeling of the atmosphere and an iterative treatment to obtain the best solution within a given framework. AIMS: We present an overview of different techniques for the quanti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03137v2-abstract-full').style.display = 'inline'; document.getElementById('2407.03137v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.03137v2-abstract-full" style="display: none;"> CONTEXT: The spectral analysis of hot, massive stars is a fundamental astrophysical method to obtain their intrinsic properties and their feedback. Quantitative spectroscopy for hot, massive stars requires detailed numerical modeling of the atmosphere and an iterative treatment to obtain the best solution within a given framework. AIMS: We present an overview of different techniques for the quantitative spectroscopy of hot stars employed within the X-Shooting ULLYSES collaboration, from grid-based approaches to tailored fits. By performing a blind test, we gain an overview about the similarities and differences of the resulting parameters. Our study aims to provide an overview of the parameter spread caused by different approaches. METHODS: For three different stars from the sample (SMC O5 star AzV 377, LMC O7 star Sk -69 50, and LMC O9 star Sk -66 171), we employ different atmosphere codes (CMFGEN, Fastwind, PoWR) and strategies to determine their best-fitting model. For our analyses, UV and optical spectra are used to derive the properties with some methods relying purely on optical data for comparison. To determine the overall spectral energy distribution, we further employ additional photometry from the literature. RESULTS: Effective temperatures for each of three sample stars agree within 3 kK while the differences in log g can be up to 0.2 dex. Luminosity differences of up to 0.1 dex result from different reddening assumptions, which seem to be larger for the methods employing a genetic algorithm. All sample stars are nitrogen-enriched. CONCLUSIONS: We find a reasonable agreement between the different methods. Tailored fitting tends to be able to minimize discrepancies obtained with more course or automatized treatments. UV spectral data is essential for the determination of realistic wind parameters. For one target (Sk -69 50), we find clear indications of an evolved status. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03137v2-abstract-full').style.display = 'none'; document.getElementById('2407.03137v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 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+15 pages, 21+4 figures, accepted version (A&A 689, A30) including language editing, condensed abstract</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 689, A30 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.01267">arXiv:2405.01267</a> <span> [<a href="https://arxiv.org/pdf/2405.01267">pdf</a>, <a href="https://arxiv.org/ps/2405.01267">ps</a>, <a href="https://arxiv.org/format/2405.01267">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive stars at low metallicity -- V. Effect of metallicity on surface abundances of O stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Martins%2C+F">F. Martins</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+-">J. -C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Hillier%2C+D+J">D. J. Hillier</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Pauli%2C+D">D. Pauli</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Ramachandran%2C+V">V. Ramachandran</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=collaboration%2C+t+X">the XshootU collaboration</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.01267v1-abstract-short" style="display: inline;"> Massive stars rotate faster, on average, than lower mass stars. Stellar rotation triggers hydrodynamical instabilities which transport angular momentum and chemical species from the core to the surface. Models of high-mass stars that include these processes predict that chemical mixing is stronger at lower metallicity. We aim to test this prediction by comparing the surface abundances of massive s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01267v1-abstract-full').style.display = 'inline'; document.getElementById('2405.01267v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.01267v1-abstract-full" style="display: none;"> Massive stars rotate faster, on average, than lower mass stars. Stellar rotation triggers hydrodynamical instabilities which transport angular momentum and chemical species from the core to the surface. Models of high-mass stars that include these processes predict that chemical mixing is stronger at lower metallicity. We aim to test this prediction by comparing the surface abundances of massive stars at different metallicities. We performed a spectroscopic analysis of single O stars in the Magellanic Clouds (MCs) based on the ULLYSES and XshootU surveys. We determined the fundamental parameters and helium, carbon, nitrogen, and oxygen surface abundances of 17 LMC and 17 SMC non-supergiant O6-9.5 stars. We complemented these determinations by literature results for additional MCs and also Galactic stars to increase the sample size and metallicity coverage. We investigated the differences in the surface chemical enrichment at different metallicities and compared them with predictions of three sets of evolutionary models. Surface abundances are consistent with CNO-cycle nucleosynthesis. The maximum surface nitrogen enrichment is stronger in MC stars than in Galactic stars. Nitrogen enrichment is also observed in stars with higher surface gravities in the SMC than in the Galaxy. This trend is predicted by models that incorporate chemical transport caused by stellar rotation. The distributions of projected rotational velocities in our samples are likely biased towards slow rotators. A metallicity dependence of surface abundances is demonstrated. The analysis of larger samples with an unbiased distribution of projected rotational velocities is required to better constrain the treatment of chemical mixing and angular momentum transport in massive single and binary stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01267v1-abstract-full').style.display = 'none'; document.getElementById('2405.01267v1-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages + appendix. Accepted 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/2404.02970">arXiv:2404.02970</a> <span> [<a href="https://arxiv.org/pdf/2404.02970">pdf</a>, <a href="https://arxiv.org/format/2404.02970">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Towards early-type eclipsing binaries as extragalactic milestones: III. Physical properties of the O-type eclipsing binary OGLE LMC-ECL-21568 in a quadruple system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Taormina%2C+M">M贸nica Taormina</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R+-">R. -P. Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Pilecki%2C+B">B. Pilecki</a>, <a href="/search/astro-ph?searchtype=author&query=Pietrzy%C5%84ski%2C+G">G. Pietrzy艅ski</a>, <a href="/search/astro-ph?searchtype=author&query=Thompson%2C+I+B">I. B. Thompson</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3rski%2C+M">M. G贸rski</a>, <a href="/search/astro-ph?searchtype=author&query=Zgirski%2C+B">B. Zgirski</a>, <a href="/search/astro-ph?searchtype=author&query=Graczyk%2C+D">D. Graczyk</a>, <a href="/search/astro-ph?searchtype=author&query=Gieren%2C+W">W. Gieren</a>, <a href="/search/astro-ph?searchtype=author&query=Hajdu%2C+G">G. Hajdu</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="2404.02970v1-abstract-short" style="display: inline;"> We present the results from a complex study of an eclipsing O-type binary (Aa+Ab) with the orbital period $P_{A}=3.2254367$ days, that forms part of a higher-order multiple system in a configuration (A+B)+C. We derived masses of the Aa+Ab binary $M_{1}= 19.02 \pm 0.12 \,M_\odot$, $M_{2}= 17.50 \pm 0.13 \,M_\odot$, radii $R_{1}= 7.70 \pm 0.05 \,R_\odot$, $R_{2}= 6.64 \pm 0.06 \,R_\odot$, and temper… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.02970v1-abstract-full').style.display = 'inline'; document.getElementById('2404.02970v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.02970v1-abstract-full" style="display: none;"> We present the results from a complex study of an eclipsing O-type binary (Aa+Ab) with the orbital period $P_{A}=3.2254367$ days, that forms part of a higher-order multiple system in a configuration (A+B)+C. We derived masses of the Aa+Ab binary $M_{1}= 19.02 \pm 0.12 \,M_\odot$, $M_{2}= 17.50 \pm 0.13 \,M_\odot$, radii $R_{1}= 7.70 \pm 0.05 \,R_\odot$, $R_{2}= 6.64 \pm 0.06 \,R_\odot$, and temperatures $T_1 = 34250 \pm 500 $ K, $T_2 = 33750 \pm 500 $ K. From the analysis of radial velocities, we found a spectroscopic orbit of A in the outer A+B system with $P_{A+B}=195.8$ days ($P_{A+B}/P_{A}\approx 61$). In the O-C analysis, we confirmed this orbit and found another component orbiting the A+B system with $P_{AB+C}=2550$ days ($P_{AB+C}\,/P_{A+B}\approx 13$). From the total mass of the inner binary and its outer orbit, we estimated the mass of the third object, $M_B \gtrsim 10.7 M_\odot$. From the light-travel time effect fit to the O-C data, we obtained the limit for the mass of the fourth component, $M_C \gtrsim 7.3 M_\odot$. These extra components contribute to about 20% to 30% (increasing with wavelength) of the total system light. From the comparison of model spectra with the multiband photometry, we derived a distance modulus of 18.59 $\pm$ 0.06 mag, a reddening of 0.16 $\pm$ 0.02 mag, and an $R_V$ of $3.2$. This work is part of our ongoing project, which aims to calibrate the surface brightness-color relation for early-type stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.02970v1-abstract-full').style.display = 'none'; document.getElementById('2404.02970v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">15 pages, 14 figures, 3 tables, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.00241">arXiv:2312.00241</a> <span> [<a href="https://arxiv.org/pdf/2312.00241">pdf</a>, <a href="https://arxiv.org/format/2312.00241">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/10.1051/0004-6361/202348808">10.1051/0004-6361/202348808 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The IACOB project X. Large-scale quantitative spectroscopic analysis of Galactic luminous blue stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=de+Burgos%2C+A">Abel de Burgos</a>, <a href="/search/astro-ph?searchtype=author&query=Sim%C3%B3n-D%C3%ADaz%2C+S">Sergio Sim贸n-D铆az</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=Puls%2C+J">Joachim Puls</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="2312.00241v2-abstract-short" style="display: inline;"> Blue supergiants (BSGs) are key objects for understanding the evolution of massive stars. However, discrepancies between theoretical predictions and empirical observations have opened up important questions yet to be answered. Studying statistically significant and unbiased samples of BSGs can help to improve the situation. We aim to perform a homogeneous and comprehensive quantitative spectroscop… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.00241v2-abstract-full').style.display = 'inline'; document.getElementById('2312.00241v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.00241v2-abstract-full" style="display: none;"> Blue supergiants (BSGs) are key objects for understanding the evolution of massive stars. However, discrepancies between theoretical predictions and empirical observations have opened up important questions yet to be answered. Studying statistically significant and unbiased samples of BSGs can help to improve the situation. We aim to perform a homogeneous and comprehensive quantitative spectroscopic analysis of a large sample of Galactic luminous blue stars (being the majority BSGs) from the IACOB spectroscopic database. We derive the projected rotational velocity ($v\sin i$) and macroturbulent broadening ($v_{\rm mac}$) using IACOB-BROAD. We used FASTWIND computations to derive effective temperatures ($T_{\rm eff}$), surface gravities, microturbulences ($尉$), Si and He surface abundances, and the wind-strength parameter. We provide estimates of these quantities for the largest sample of Galactic luminous O9-B5 stars spectroscopically analyzed to date, with 527 targets. We find a drop in the relative number of stars at ~21 kK, coinciding with a scarcity of fast rotating stars below that temperature. We speculate that this feature might be roughly delineating the location of the Terminal-Age-Main-Sequence in the 15-85M$_\odot$ range. By investigating the main characteristics of the $v\sin i$ distribution as a function of $T_{\rm eff}$, we propose that an efficient mechanism transporting angular momentum from the stellar core to the surface might be operating along the main sequence. We find correlations between $尉$, $v_{\rm mac}$ and the spectroscopic luminosity. We also find that no more than 20% of the stars in our sample have atmospheres clearly enriched in He, and suggest that the origin of this specific sub-sample might be in binary evolution. We do not find clear empirical evidence of an increase in the wind-strength over the wind bi-stability region towards lower temperatures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.00241v2-abstract-full').style.display = 'none'; document.getElementById('2312.00241v2-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy and Astrophysics, 22 pages, 20 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 687, A228 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.10615">arXiv:2309.10615</a> <span> [<a href="https://arxiv.org/pdf/2309.10615">pdf</a>, <a href="https://arxiv.org/ps/2309.10615">ps</a>, <a href="https://arxiv.org/format/2309.10615">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/10.1051/0004-6361/202346487">10.1051/0004-6361/202346487 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> To clump or not to clump The impact of wind inhomogeneities on the optical and NIR spectroscopic analysis of massive OB stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=R%C3%BCbke%2C+K">K. R眉bke</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</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="2309.10615v1-abstract-short" style="display: inline;"> Winds of massive stars have density inhomogeneities (clumping) that may affect the formation of spectral lines in different ways, depending on their formation region. Most of previous and current spectroscopic analyses have been performed in the optical or ultraviolet domain. However, massive stars are often hidden behind dense clouds rendering near-infrared observations necessary. Our objective i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.10615v1-abstract-full').style.display = 'inline'; document.getElementById('2309.10615v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.10615v1-abstract-full" style="display: none;"> Winds of massive stars have density inhomogeneities (clumping) that may affect the formation of spectral lines in different ways, depending on their formation region. Most of previous and current spectroscopic analyses have been performed in the optical or ultraviolet domain. However, massive stars are often hidden behind dense clouds rendering near-infrared observations necessary. Our objective is to investigate whether a spectroscopic analysis using either optical or infrared observations results in the same stellar parameters with comparable accuracy, and whether clumping affects them in different ways. We analyzed optical and near-infrared observations of a set of massive O stars with spectral types O4-O9.5 and all luminosity classes. We obtain similar stellar parameters in the optical and the infrared, although with larger uncertainties in the near-infrared, both with and without clumping, albeit with some individual deviating cases. We find that the inclusion of clumping improves the fit to H$_伪$ or HeII 4686 in the optical for supergiants, as well as that of Br$_纬$ in the near-infrared, but it sometimes worsens the fit to HeII 2.18$渭$m. Globally, there are no significant differences when using the clumping laws tested in this work. The infrared can be used for spectroscopic analyses, giving similar parameters as from the optical, though with larger uncertainties. The best fits to different lines are obtained with different (linear) clumping laws, indicating that the wind structure may be more complex than adopted in the present work. No clumping law results in a better global fit, or improves the consistency between optical and infrared stellar parameters. Our work shows that the optical and infrared lines are not sufficient to break the dichotomy between the mass-loss rate and clumping factor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.10615v1-abstract-full').style.display = 'none'; document.getElementById('2309.10615v1-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 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 679, A19 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.12165">arXiv:2303.12165</a> <span> [<a href="https://arxiv.org/pdf/2303.12165">pdf</a>, <a href="https://arxiv.org/format/2303.12165">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/10.1051/0004-6361/202245588">10.1051/0004-6361/202245588 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> X-Shooting ULLYSES: Massive stars at low metallicity. III. Terminal wind speeds of ULLYSES massive stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">C. Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Decin%2C+L">L. Decin</a>, <a href="/search/astro-ph?searchtype=author&query=Erba%2C+C">C. Erba</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Hamann%2C+W+-">W. -R. Hamann</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Ignace%2C+R">R. Ignace</a>, <a href="/search/astro-ph?searchtype=author&query=Kee%2C+N+D">N. D. Kee</a>, <a href="/search/astro-ph?searchtype=author&query=Kub%C3%A1tov%C3%A1%2C+B">B. Kub谩tov谩</a>, <a href="/search/astro-ph?searchtype=author&query=Lefever%2C+R">R. Lefever</a>, <a href="/search/astro-ph?searchtype=author&query=Moffat%2C+A">A. Moffat</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L">L. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Pauli%2C+D">D. Pauli</a>, <a href="/search/astro-ph?searchtype=author&query=Prinja%2C+R">R. Prinja</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A+A+C">A. A. C. Sander</a> , et al. (4 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="2303.12165v2-abstract-short" style="display: inline;"> The winds of massive stars have an impact on stellar evolution and on the surrounding medium. The maximum speed reached by these outflows, the terminal wind speed, is a global wind parameter and an essential input for models of stellar atmospheres and feedback. With the arrival of the ULLYSES programme, a legacy UV spectroscopic survey with HST, we have the opportunity to quantify the wind speeds… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12165v2-abstract-full').style.display = 'inline'; document.getElementById('2303.12165v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.12165v2-abstract-full" style="display: none;"> The winds of massive stars have an impact on stellar evolution and on the surrounding medium. The maximum speed reached by these outflows, the terminal wind speed, is a global wind parameter and an essential input for models of stellar atmospheres and feedback. With the arrival of the ULLYSES programme, a legacy UV spectroscopic survey with HST, we have the opportunity to quantify the wind speeds of massive stars at sub-solar metallicity (in the Large and Small Magellanic Clouds, 0.5Z and 0.2Z) at an unprecedented scale. We empirically quantify the wind speeds of a large sample of OB stars, including supergiants, giants, and dwarfs at sub-solar metallicity. Using these measurements, we investigate trends of terminal wind speed with a number of fundamental stellar parameters, namely effective temperature, metallicity, and surface escape velocity. We empirically determined the terminal wind speed for a sample of 149 OB stars in the Magellanic Clouds either by directly measuring the maximum velocity shift of the absorption component of the Civ 1548-1550 line profile, or by fitting synthetic spectra produced using the Sobolev with exact integration method. Stellar parameters were either collected from the literature, obtained using spectral-type calibrations, or predicted from evolutionary models. We find strong trends of terminal wind speed with effective temperature and surface escape speed when the wind is strong enough to cause a saturated P Cygni profile in Civ 1548-1550. We find evidence for a metallicity dependence on the terminal wind speed proportional to Z^0.22+-0.03 when we compared our results to previous Galactic studies. Our results suggest that effective temperature rather than surface escape speed should be used as a straightforward empirical prediction of terminal wind speed and that the observed metallicity dependence is steeper than suggested by earlier works. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12165v2-abstract-full').style.display = 'none'; document.getElementById('2303.12165v2-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">21 pages, 16 figures, 8 tables. Accepted 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 688, A105 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.10992">arXiv:2302.10992</a> <span> [<a href="https://arxiv.org/pdf/2302.10992">pdf</a>, <a href="https://arxiv.org/format/2302.10992">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/10.1051/0004-6361/202245281">10.1051/0004-6361/202245281 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A model of anisotropic winds from rotating stars for evolutionary calculations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hastings%2C+B">Ben Hastings</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2302.10992v1-abstract-short" style="display: inline;"> Context: The surface properties of rotating stars can vary from pole to equator, resulting in anisotropic stellar winds which are not included in the currently available evolutionary models. Aims: We develop a formalism to describe the mass and angular momentum loss of rotating stars which takes into account both the varying surface properties and distortion due to rotation. Methods: Adopting… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.10992v1-abstract-full').style.display = 'inline'; document.getElementById('2302.10992v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.10992v1-abstract-full" style="display: none;"> Context: The surface properties of rotating stars can vary from pole to equator, resulting in anisotropic stellar winds which are not included in the currently available evolutionary models. Aims: We develop a formalism to describe the mass and angular momentum loss of rotating stars which takes into account both the varying surface properties and distortion due to rotation. Methods: Adopting the mass-loss recipe for non-rotating stars, we assigned to each point on the surface of a rotating star an equivalent non-rotating star, for which the surface mass flux is given by the recipe. The global mass-loss and angular momentum loss rates are then given by integrating over the deformed stellar surface as appropriate. Evolutionary models were computed and our prescription is compared to the currently used simple mass-loss enhancement recipes for rotating stars. Results: We find that mass-loss rates are largely insensitive to rotation for models not affected by the bi-stability jump. For those affected by the bi-stability jump, the increase in mass-loss rates with respect to time is smoothed. As our prescription considers the variation of physical conditions over the stellar surface, the region affected by the bi-stability jump is able to grow gradually instead of the whole star suddenly being affected. Conclusion: We have provided an easy to implement and flexible, yet physically meaningful prescription for calculating mass and angular momentum loss rates of rotating stars in a one-dimensional stellar evolution code which compares favourably to more physically comprehensive models. The implementation of our scheme in the stellar evolution code MESA is available online: https://zenodo.org/record/7437006 <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.10992v1-abstract-full').style.display = 'none'; document.getElementById('2302.10992v1-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, 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">Accepted for publication in A&A. 12 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 672, A60 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.07060">arXiv:2211.07060</a> <span> [<a href="https://arxiv.org/pdf/2211.07060">pdf</a>, <a href="https://arxiv.org/format/2211.07060">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> </div> <p class="title is-5 mathjax"> Spin-down and reduced mass loss in early-type stars with large-scale magnetic fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Z. Keszthelyi</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=G%C3%B6tberg%2C+Y">Y. G枚tberg</a>, <a href="/search/astro-ph?searchtype=author&query=Meynet%2C+G">G. Meynet</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Carrington%2C+M">M. Carrington</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Geen%2C+S+T">S. T. Geen</a>, <a href="/search/astro-ph?searchtype=author&query=Georgy%2C+C">C. Georgy</a>, <a href="/search/astro-ph?searchtype=author&query=Hirschi%2C+R">R. Hirschi</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Ramalatswa%2C+K+J">K. J. Ramalatswa</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2211.07060v1-abstract-short" style="display: inline;"> Magnetism can greatly impact the evolution of stars. In some stars with OBA spectral types there is direct evidence via the Zeeman effect for stable, large-scale magnetospheres, which lead to the spin-down of the stellar surface and reduced mass loss. So far, a comprehensive grid of stellar structure and evolution models accounting for these effects was lacking. For this reason, we computed and st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.07060v1-abstract-full').style.display = 'inline'; document.getElementById('2211.07060v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.07060v1-abstract-full" style="display: none;"> Magnetism can greatly impact the evolution of stars. In some stars with OBA spectral types there is direct evidence via the Zeeman effect for stable, large-scale magnetospheres, which lead to the spin-down of the stellar surface and reduced mass loss. So far, a comprehensive grid of stellar structure and evolution models accounting for these effects was lacking. For this reason, we computed and studied models with two magnetic braking and two chemical mixing schemes in three metallicity environments with the MESA software instrument. We find notable differences between the subgrids, which affects the model predictions and thus the detailed characterisation of stars. We are able to quantify the impact of magnetic fields in terms of preventing quasi-chemically homogeneous evolution and producing slowly-rotating, nitrogen-enriched ("Group 2") stars. Our model grid is fully open access and open source. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.07060v1-abstract-full').style.display = 'none'; document.getElementById('2211.07060v1-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 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">to appear in "Winds of Stars and Exoplanets" Proceedings IAUS 370, 2022, eds.: A.A. Vidotto, L. Fossati, J.S. Vink</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.06350">arXiv:2209.06350</a> <span> [<a href="https://arxiv.org/pdf/2209.06350">pdf</a>, <a href="https://arxiv.org/format/2209.06350">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stac2598">10.1093/mnras/stac2598 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The effects of surface fossil magnetic fields on massive star evolution: IV. Grids of models at Solar, LMC, and SMC metallicities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Z. Keszthelyi</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=G%C3%B6tberg%2C+Y">Y. G枚tberg</a>, <a href="/search/astro-ph?searchtype=author&query=Meynet%2C+G">G. Meynet</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Carrington%2C+M">M. Carrington</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Geen%2C+S+T">S. T. Geen</a>, <a href="/search/astro-ph?searchtype=author&query=Georgy%2C+C">C. Georgy</a>, <a href="/search/astro-ph?searchtype=author&query=Hirschi%2C+R">R. Hirschi</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Ramalatswa%2C+K+J">K. J. Ramalatswa</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+A">A. ud-Doula</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.06350v2-abstract-short" style="display: inline;"> Magnetic fields can drastically change predictions of evolutionary models of massive stars via mass-loss quenching, magnetic braking, and efficient angular momentum transport, which we aim to quantify in this work. We use the MESA software instrument to compute an extensive main-sequence grid of stellar structure and evolution models, as well as isochrones, accounting for the effects attributed to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.06350v2-abstract-full').style.display = 'inline'; document.getElementById('2209.06350v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.06350v2-abstract-full" style="display: none;"> Magnetic fields can drastically change predictions of evolutionary models of massive stars via mass-loss quenching, magnetic braking, and efficient angular momentum transport, which we aim to quantify in this work. We use the MESA software instrument to compute an extensive main-sequence grid of stellar structure and evolution models, as well as isochrones, accounting for the effects attributed to a surface fossil magnetic field. The grid is densely populated in initial mass (3-60 M$_\odot$), surface equatorial magnetic field strength (0-50 kG), and metallicity (representative of the Solar neighbourhood and the Magellanic Clouds). We use two magnetic braking and two chemical mixing schemes and compare the model predictions for slowly-rotating, nitrogen-enriched ("Group 2") stars with observations in the Large Magellanic Cloud. We quantify a range of initial field strengths that allow for producing Group 2 stars and find that typical values (up to a few kG) lead to solutions. Between the subgrids, we find notable departures in surface abundances and evolutionary paths. In our magnetic models, chemical mixing is always less efficient compared to non-magnetic models due to the rapid spin-down. We identify that quasi-chemically homogeneous main sequence evolution by efficient mixing could be prevented by fossil magnetic fields. We recommend comparing this grid of evolutionary models with spectropolarimetric and spectroscopic observations with the goals of i) revisiting the derived stellar parameters of known magnetic stars, and ii) observationally constraining the uncertain magnetic braking and chemical mixing schemes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.06350v2-abstract-full').style.display = 'none'; document.getElementById('2209.06350v2-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 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 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">Accepted for publication in MNRAS. A full reproduction package is available on Zenodo at https://doi.org/10.5281/zenodo.7069766</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.08218">arXiv:2203.08218</a> <span> [<a href="https://arxiv.org/pdf/2203.08218">pdf</a>, <a href="https://arxiv.org/format/2203.08218">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars III. Updated mass-loss rates for stellar evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bj%C3%B6rklund%2C+R">R. Bj枚rklund</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Singh%2C+S+M">S. M. Singh</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2203.08218v1-abstract-short" style="display: inline;"> Massive stars lose a large fraction of their mass to radiation-driven winds throughout their entire life. These outflows impact both the life and death of these stars and their surroundings. Theoretical mass-loss rates of hot, massive stars are derived to be used in applications such as stellar evolution. The behaviour of these rates in the OB-star regime is analysed, and their effects on massive-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.08218v1-abstract-full').style.display = 'inline'; document.getElementById('2203.08218v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.08218v1-abstract-full" style="display: none;"> Massive stars lose a large fraction of their mass to radiation-driven winds throughout their entire life. These outflows impact both the life and death of these stars and their surroundings. Theoretical mass-loss rates of hot, massive stars are derived to be used in applications such as stellar evolution. The behaviour of these rates in the OB-star regime is analysed, and their effects on massive-star evolution predictions is studied. Dynamically-consistent models are computed by solving the spherically symmetric, steady-state equation-of-motion for a large grid of hot, massive stars. The radiative acceleration is derived from non-local thermodynamic equilibrium radiative transfer in the co-moving frame. The resulting mass-loss rates are used to derive a simple scaling recipe with stellar parameters and to evaluate some first impacts upon evolution tracks. We provide a new prescription for steady-state, radiation-driven mass-loss from hot, massive stars depending on their fundamental parameters. The rates for O-stars are lower by about a factor ~3 than the rates typically used in previous stellar-evolution calculations, where differences generally decrease with increasing luminosity and temperature. For cooler B-giants/supergiants we find larger discrepancies. This arises because we do not find any systematic increase in mass-loss rates below the so-called bi-stability region; indeed, our results do not show any sign of a significant bi-stability jump within the parameter range covered by the grid. Due to the lower mass-loss rates we find that envelopes are not easily stripped by means of standard steady-state winds, making it difficult to create classical Wolf-Rayet stars via this channel. However, a remaining key uncertainty regarding these predictions concerns unsteady mass loss for very high-luminosity stars close to the Eddington limit as well as the impact of non-line-driven winds. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.08218v1-abstract-full').style.display = 'none'; document.getElementById('2203.08218v1-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 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">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/2203.03308">arXiv:2203.03308</a> <span> [<a href="https://arxiv.org/pdf/2203.03308">pdf</a>, <a href="https://arxiv.org/format/2203.03308">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/10.1093/mnras/stac625">10.1093/mnras/stac625 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Metallicity Estimation of Core-Collapse Supernova HII Regions in Galaxies within 30 Mpc </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ganss%2C+R">R. Ganss</a>, <a href="/search/astro-ph?searchtype=author&query=Pledger%2C+J+L">J. L. Pledger</a>, <a href="/search/astro-ph?searchtype=author&query=Sansom%2C+A+E">A. E. Sansom</a>, <a href="/search/astro-ph?searchtype=author&query=James%2C+P+A">P. A. James</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Habergham-Mawson%2C+S+M">S. M. Habergham-Mawson</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="2203.03308v2-abstract-short" style="display: inline;"> This work presents measurements of the local HII environment metallicities of core-collapse supernovae (SNe) within a luminosity distance of 30 Mpc. 76 targets were observed at the Isaac Newton Telescope and environment metallicities could be measured for 65 targets using the N2 and O3N2 strong emission line method. The cumulative distribution functions (CDFs) of the environment metallicities of T… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.03308v2-abstract-full').style.display = 'inline'; document.getElementById('2203.03308v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.03308v2-abstract-full" style="display: none;"> This work presents measurements of the local HII environment metallicities of core-collapse supernovae (SNe) within a luminosity distance of 30 Mpc. 76 targets were observed at the Isaac Newton Telescope and environment metallicities could be measured for 65 targets using the N2 and O3N2 strong emission line method. The cumulative distribution functions (CDFs) of the environment metallicities of Type Ib and Ic SNe tend to higher metallicity than Type IIP, however Type Ic are also present at lower metallicities whereas Type Ib are not. The Type Ib frequency distribution is narrower (standard deviation $\sim$0.06 dex) than the Ic and IIP distributions ($\sim$0.15 dex) giving some evidence for a significant fraction of single massive progenitor stars; the low metallicity of Type Ic suggests a significant fraction of compact binary progenitors. However, both the Kolmogorov-Smirnov test and the Anderson-Darling test indicate no statistical significance for a difference in the local metallicities of the three SN types. Monte-Carlo simulations reveal a strong sensitivity of these tests to the uncertainties of the derived metallicities. Given the uncertainties of the strong emission methods, the applicability of the tests seems limited. We extended our analysis with the data of the Type Ib/Ic/IIP SN sample from Galbany et al. (2018). The CDFs created with their sample confirm our CDFs very well. The statistical tests, combining our sample and the Galbany et al. (2018) sample, indicate a significant difference between Type Ib and Type IIP with <5% probability that they are drawn from the same parent population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.03308v2-abstract-full').style.display = 'none'; document.getElementById('2203.03308v2-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 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">19 pages, 10 figures, 10 tables, accepted for publication in MNRAS, minor changes at editor's request</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, Volume 512, Issue 1, May 2022, Pages 1541-1556 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.11806">arXiv:2202.11806</a> <span> [<a href="https://arxiv.org/pdf/2202.11806">pdf</a>, <a href="https://arxiv.org/format/2202.11806">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/stab3660">10.1093/mnras/stab3660 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The nature of the Cygnus extreme B-supergiant 2MASS J20395358+4222505 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</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=de+Paz%2C+A+G">A. Gil de Paz</a>, <a href="/search/astro-ph?searchtype=author&query=Comer%C3%B3n%2C+F">F. Comer贸n</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Alegr%C3%ADa%2C+S+R">S. Ram铆rez Alegr铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa%2C+M">M. Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <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=Urbaneja%2C+M+A">M. A. Urbaneja</a>, <a href="/search/astro-ph?searchtype=author&query=Gallego%2C+J">J. Gallego</a>, <a href="/search/astro-ph?searchtype=author&query=Carrasco%2C+E">E. Carrasco</a>, <a href="/search/astro-ph?searchtype=author&query=Iglesias%2C+J">J. Iglesias</a>, <a href="/search/astro-ph?searchtype=author&query=Cedazo%2C+R">R. Cedazo</a>, <a href="/search/astro-ph?searchtype=author&query=Vargas%2C+M+L+G">M. L. Garc铆a Vargas</a>, <a href="/search/astro-ph?searchtype=author&query=Castillo-Morales%2C+A">A. Castillo-Morales</a>, <a href="/search/astro-ph?searchtype=author&query=Pascual%2C+S">S. Pascual</a>, <a href="/search/astro-ph?searchtype=author&query=Cardiel%2C+N">N. Cardiel</a>, <a href="/search/astro-ph?searchtype=author&query=P%C3%A9rez-Calpena%2C+A">A. P茅rez-Calpena</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%B3mez-Alvarez%2C+P">P. G贸mez-Alvarez</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-Delgado%2C+I">I. Mart铆nez-Delgado</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="2202.11806v1-abstract-short" style="display: inline;"> 2MASS J20395358+4222505 is an obscured early B supergiant near the massive OB star association Cyg OB2. Despite its bright infrared magnitude (K$_{s}$=5.82) it has remained largely ignored because of its dim optical magnitude (B=16.63, V=13.68). In a previous paper we classified it as a highly reddened, potentially extremely luminous, early B-type supergiant. We obtained its spectrum in the U, B a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.11806v1-abstract-full').style.display = 'inline'; document.getElementById('2202.11806v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.11806v1-abstract-full" style="display: none;"> 2MASS J20395358+4222505 is an obscured early B supergiant near the massive OB star association Cyg OB2. Despite its bright infrared magnitude (K$_{s}$=5.82) it has remained largely ignored because of its dim optical magnitude (B=16.63, V=13.68). In a previous paper we classified it as a highly reddened, potentially extremely luminous, early B-type supergiant. We obtained its spectrum in the U, B and R spectral bands during commissioning observations with the instrument MEGARA@GTC. It displays a particularly strong H$伪$ emission for its spectral type, B1 Ia. The star seems to be in an intermediate phase between super- and hypergiant, a group that it will probably join in the near (astronomical) future. We observe a radial velocity difference between individual observations and determine the stellar parameters, obtaining T$_{eff}$ = 24000 K, logg$_{c}$= 2.88 $\pm$ 0.15. The rotational velocity found is large for a B-supergiant, vsini= 110 $\pm$ 25 km s$^{-1}$. The abundance pattern is consistent with solar, with a mild C underabundance (based on a single line). Assuming that J20395358+4222505 is at the distance of Cyg OB2 we derive the radius from infrared photometry, finding R= 41.2 $\pm$ 4.0 R$_{\odot}$, log(L/L$_{\odot}$)= 5.71 $\pm$ 0.04 and a spectroscopic mass of 46.5 $\pm$ 15.0 M$_{\odot}$. The clumped mass-loss rate (clumping factor 10) is very high for the spectral type, $\dot{M}$ = 2.4x10$^{-6}$ M$_{\odot}$ a$^{-1}$. The high rotational velocity and mass-loss rate place the star at the hot side of the bi-stability jump. Together with the nearly solar CNO abundance pattern, they may also point to evolution in a binary system, J20395358+4222505 being the initial secondary. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.11806v1-abstract-full').style.display = 'none'; document.getElementById('2202.11806v1-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 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">Accepted for publication in MNRAS, 13 pages, 9 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.11080">arXiv:2202.11080</a> <span> [<a href="https://arxiv.org/pdf/2202.11080">pdf</a>, <a href="https://arxiv.org/format/2202.11080">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/10.1051/0004-6361/202142742">10.1051/0004-6361/202142742 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The R136 star cluster dissected with Hubble Space Telescope/STIS. III. The most massive stars and their clumped winds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">Sarah A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">Alex de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">Joachim M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">Paul A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero-Nieves%2C+S+M">Saida M. Caballero-Nieves</a>, <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">Michael Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Driessen%2C+F+A">Florian A. Driessen</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa%2C+M">Miriam Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Geen%2C+S">Sam Geen</a>, <a href="/search/astro-ph?searchtype=author&query=Gr%C3%A4fener%2C+G">G枚tz Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">Calum Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Kaper%2C+L">Lex Kaper</a>, <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Zsolt Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">Hugues Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">Fabian R. N. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Shenar%2C+T">Tomer Shenar</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">Jorick S. Vink</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="2202.11080v1-abstract-short" style="display: inline;"> Context: The star cluster R136 inside the LMC hosts a rich population of massive stars, including the most massive stars known. The strong stellar winds of these very luminous stars impact their evolution and the surrounding environment. We currently lack detailed knowledge of the wind structure that is needed to quantify this impact. Aims: To observationally constrain the stellar and wind propert… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.11080v1-abstract-full').style.display = 'inline'; document.getElementById('2202.11080v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.11080v1-abstract-full" style="display: none;"> Context: The star cluster R136 inside the LMC hosts a rich population of massive stars, including the most massive stars known. The strong stellar winds of these very luminous stars impact their evolution and the surrounding environment. We currently lack detailed knowledge of the wind structure that is needed to quantify this impact. Aims: To observationally constrain the stellar and wind properties of the massive stars in R136, in particular the parameters related to wind clumping. Methods: We simultaneously analyse optical and UV spectroscopy of 53 O-type and 3 WNh-stars using the FASTWIND model atmosphere code and a genetic algorithm. The models account for optically thick clumps and effects related to porosity and velocity-porosity, as well as a non-void interclump medium. Results: We obtain stellar parameters, surface abundances, mass-loss rates, terminal velocities and clumping characteristics and compare these to theoretical predictions and evolutionary models. The clumping properties include the density of the interclump medium and the velocity-porosity of the wind. For the first time, these characteristics are systematically measured for a wide range of effective temperatures and luminosities. Conclusions: We confirm a cluster age of 1.0-2.5 Myr and derive an initial stellar mass of $\geq 250 {\rm M}_\odot$ for the most massive star in our sample, R136a1. The winds of our sample stars are highly clumped, with an average clumping factor of $f_{\rm cl}=29\pm15$. We find tentative trends in the wind-structure parameters as a function of mass-loss rate, suggesting that the winds of stars with higher mass-loss rates are less clumped. We compare several theoretical predictions to the observed mass-loss rates and terminal velocities and find that none satisfactorily reproduces both quantities. The prescription of Krti膷ka & Kub谩t (2018) matches best the observed mass-loss rates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.11080v1-abstract-full').style.display = 'none'; document.getElementById('2202.11080v1-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, 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">Accepted for publication in A&A; Appendix I will not be included in the published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 663, A36 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.11734">arXiv:2108.11734</a> <span> [<a href="https://arxiv.org/pdf/2108.11734">pdf</a>, <a href="https://arxiv.org/format/2108.11734">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/10.1051/0004-6361/202040116">10.1051/0004-6361/202040116 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Upper Mass-Loss Limits and Clumping in the Intermediate and Outer Wind Regions of OB stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Rubio-D%C3%ADez%2C+M+M">M. M. Rubio-D铆ez</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Traficante%2C+A">A. Traficante</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Calzoletti%2C+L">L. Calzoletti</a>, <a href="/search/astro-ph?searchtype=author&query=Figer%2C+D">D. Figer</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="2108.11734v1-abstract-short" style="display: inline;"> We probe the radial clumping stratification of OB stars in the intermediate and outer wind regions (r>~2 R*) to derive upper limits for mass-loss rates, and compare to current mass-loss implementation. Together with archival multi-wavelength data, our new far-infrared continuum observations for a sample of 25 OB stars (including 13 B Supergiants) uniquely constrain the clumping properties of the i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11734v1-abstract-full').style.display = 'inline'; document.getElementById('2108.11734v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.11734v1-abstract-full" style="display: none;"> We probe the radial clumping stratification of OB stars in the intermediate and outer wind regions (r>~2 R*) to derive upper limits for mass-loss rates, and compare to current mass-loss implementation. Together with archival multi-wavelength data, our new far-infrared continuum observations for a sample of 25 OB stars (including 13 B Supergiants) uniquely constrain the clumping properties of the intermediate wind region. We derive the minimum radial stratification of the clumping factor through the stellar wind, fclmin(r), and the corresponding maximum mass-loss rate, Mdotmax, normalising clumping factors to the outermost wind region (clfar=1). The clumping degree for r>~2 R* decreases or stays constant with increasing radius for almost the whole sample. There is a dependence on luminosity class and spectral type at the intermediate region relative to the outer ones: O Supergiants (OSGs) present a factor 2 larger clumping factors than B Supergiants (BSGs). The maximum clumping of roughly 1/3 of the OB Supergiants occurs close to the wind base (r<~2 R*) and then decreases monotonically. This contrasts with the more frequent case where the lowermost clumping increases towards a maximum, and needs to be addressed by theoretical models. Additionally, the estimated Mdotmax for BSGs is at least one order of magnitude lower than theoretical values, whereas for OSGs our results and predictions agree within errors. Assuming values of clfar=4-9 from hydrodynamical models would imply a reduction of mass-loss rates included in stellar evolution models by a factor 2-3 for OSGs and by factors 6-200 for BSGs below the first bi-stability jump. This implies large reductions of mass-loss rates applied in evolution-models for BSGs, independently of the actual clumping properties of these winds, and a thorough re-investigation of BSG mass-loss rates and their effects on stellar evolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11734v1-abstract-full').style.display = 'none'; document.getElementById('2108.11734v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 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">23 pages + 12 appendices pages, 18 figures, accepted 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 658, A61 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.08340">arXiv:2108.08340</a> <span> [<a href="https://arxiv.org/pdf/2108.08340">pdf</a>, <a href="https://arxiv.org/format/2108.08340">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/10.1051/0004-6361/202140603">10.1051/0004-6361/202140603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Empirical mass-loss rates and clumping properties of Galactic early-type O supergiants </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">C. Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">M. Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Bouret%2C+J+C">J. C. Bouret</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">S. A. Brands</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=Driessen%2C+F+A">F. A. Driessen</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</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="2108.08340v1-abstract-short" style="display: inline;"> We investigate the impact of optically thick clumping on stellar wind diagnostics in O supergiants and constrain wind parameters associated with porosity in velocity space. This is the first time the effects of optically thick clumping have been investigated for a sample of massive hot stars, using models including a full optically thick clumping description. We re-analyse spectroscopic observatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.08340v1-abstract-full').style.display = 'inline'; document.getElementById('2108.08340v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.08340v1-abstract-full" style="display: none;"> We investigate the impact of optically thick clumping on stellar wind diagnostics in O supergiants and constrain wind parameters associated with porosity in velocity space. This is the first time the effects of optically thick clumping have been investigated for a sample of massive hot stars, using models including a full optically thick clumping description. We re-analyse spectroscopic observations of a sample of eight O supergiants. Using a genetic algorithm wrapper around the NLTE atmosphere code FASTWIND we obtain simultaneous fits to optical and UV spectra and determine photospheric and wind properties and surface abundances. We provide empirical constraints on a number of wind parameters including the clumping factors, mass-loss rates and terminal wind velocities. Additionally, we establish the first systematic empirical constraints on velocity filling factors and interclump densities. These parameters describe clump distribution in velocity-space and density of the interclump medium in physical-space, respectively. We observe a mass-loss rate reduction of a factor of 3.6 compared to theoretical predictions from Vink et al. (2000), and mass-loss rates within a factor 1.4 of predictions from Bj枚rklund et al. (2021). We confirm that including optically thick clumping allows simultaneous fitting of recombination lines and resonance lines, including the unsaturated UV phosphorus lines (Pv 1118-1128), without reducing the phosphorus abundance. We find that, on average, half of the wind velocity field is covered by dense clumps. We also find that these clumps are 25 times denser than the average wind, and that the interclump medium is 3-10 times less dense than the mean wind. The former result agrees well with theoretical predictions, the latter suggests that lateral filling-in of radially compressed gas might be critical for setting the scale of the rarefied interclump matter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.08340v1-abstract-full').style.display = 'none'; document.getElementById('2108.08340v1-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 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">Accepted for publication in A&A; 35 pages, 20 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 655, A67 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.07621">arXiv:2104.07621</a> <span> [<a href="https://arxiv.org/pdf/2104.07621">pdf</a>, <a href="https://arxiv.org/format/2104.07621">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/10.1051/0004-6361/202040195">10.1051/0004-6361/202040195 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraining the Overcontact Phase in Massive Binary Evolution I. Mixing in V382 Cyg, VFTS 352, and OGLE SMC-SC10 108086 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">Michael Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">Hugues Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Hawcroft%2C+C">Calum Hawcroft</a>, <a href="/search/astro-ph?searchtype=author&query=Almeida%2C+L+A">Leonardo A. Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">Sarah A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">Selma E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Justham%2C+S">Stephen Justham</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">Laurent Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Marchant%2C+P">Pablo Marchant</a>, <a href="/search/astro-ph?searchtype=author&query=Menon%2C+A">Athira Menon</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">Jon Sundqvist</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="2104.07621v2-abstract-short" style="display: inline;"> As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution. Despite the importance of these systems, large uncertainties regarding the nature and efficiency of the internal mixing mechanisms still exist. In this work, we aim to provide rob… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.07621v2-abstract-full').style.display = 'inline'; document.getElementById('2104.07621v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.07621v2-abstract-full" style="display: none;"> As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution. Despite the importance of these systems, large uncertainties regarding the nature and efficiency of the internal mixing mechanisms still exist. In this work, we aim to provide robust observational constraints on the internal mixing processes by spectroscopically analyzing a sample of three massive overcontact binaries at different metallicities. Using optical phase-resolved spectroscopic data, we perform an atmosphere analysis using more traditional 1D techniques and using state-of-the-art 3D techniques. We compare and contrast the assumptions and results of each technique and investigate how the assumptions affect the final derived atmospheric parameters. We find that in all three cases, both components of system are highly overluminous indicating either efficient internal mixing of helium or previous non-conservative mass transfer. However, we do not find strong evidence of helium or CNO surface abundance changes usually associated with mixing. Additionally, we find that in unequal mass systems, the measured effective temperature and luminosity of the less massive component places it very close to the more massive component on the Hertzsprung-Russell diagram. These results were obtained independently using both of the techniques mentioned above, which suggests that these measurements are robust. The observed discrepancies between the temperature and the surface abundance measurements when compared to theoretical expectations indicate that unaccounted for additional physical mechanisms may be at play. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.07621v2-abstract-full').style.display = 'none'; document.getElementById('2104.07621v2-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 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">Accepted for publication in A&A; 28 pages, 20 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/2102.03372">arXiv:2102.03372</a> <span> [<a href="https://arxiv.org/pdf/2102.03372">pdf</a>, <a href="https://arxiv.org/format/2102.03372">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/10.1051/0004-6361/202040008">10.1051/0004-6361/202040008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mapping the core of the Tarantula Nebula with VLT-MUSE II. The spectroscopic Hertzsprung-Russell diagram of OB stars in NGC 2070 </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=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Selman%2C+F+J">F. J. Selman</a>, <a href="/search/astro-ph?searchtype=author&query=Roth%2C+M+M">M. M. Roth</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> </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="2102.03372v1-abstract-short" style="display: inline;"> We present the spectroscopic analysis of 333 OB-type stars extracted from VLT-MUSE observations of the central 30 x 30 pc of NGC 2070 in the Tarantula Nebula on the Large Magellanic Cloud, the majority of which are analysed for the the first time. The distribution of stars in the spectroscopic Hertzsprung-Russell diagram (sHRD) shows 281 stars in the main sequence. We find two groups in the main s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.03372v1-abstract-full').style.display = 'inline'; document.getElementById('2102.03372v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.03372v1-abstract-full" style="display: none;"> We present the spectroscopic analysis of 333 OB-type stars extracted from VLT-MUSE observations of the central 30 x 30 pc of NGC 2070 in the Tarantula Nebula on the Large Magellanic Cloud, the majority of which are analysed for the the first time. The distribution of stars in the spectroscopic Hertzsprung-Russell diagram (sHRD) shows 281 stars in the main sequence. We find two groups in the main sequence, with estimated ages of 2.1$\pm$0.8 and 6.2$\pm$2 Myr. A subgroup of 52 stars is apparently beyond the main sequence phase, which we consider to be due to emission-type objects and/or significant nebular contamination affecting the analysis. As in previous studies, stellar masses derived from the sHRD are systematically larger than those obtained from the conventional HRD, with the differences being largest for the most massive stars. Additionally, we do not find any trend between the estimated projected rotational velocity and evolution in the sHRD. The projected rotational velocity distribution presents a tail of fast rotators that resembles findings in the wider population of 30 Doradus. We use published spectral types to calibrate the HeI$位$4921/HeII$位$5411 equivalent-width ratio as a classification diagnostic for early-type main sequence stars when the classical blue-visible region is not observed. Our model-atmosphere analyses demonstrate that the resulting calibration is well correlated with effective temperature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.03372v1-abstract-full').style.display = 'none'; document.getElementById('2102.03372v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">19 pages, 12 figures. Accepted 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 648, A65 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.02310">arXiv:2011.02310</a> <span> [<a href="https://arxiv.org/pdf/2011.02310">pdf</a>, <a href="https://arxiv.org/ps/2011.02310">ps</a>, <a href="https://arxiv.org/format/2011.02310">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/10.1051/0004-6361/202038464">10.1051/0004-6361/202038464 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atmospheric NLTE models for the spectroscopic analysis of blue stars with winds. V. Complete comoving frame transfer, and updated modeling of X-ray emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Sen%2C+K">K. Sen</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="2011.02310v1-abstract-short" style="display: inline;"> Context. Obtaining precise stellar and wind properties and abundance patterns of massive stars is crucial to understanding their nature and interactions with their environments, as well as to constrain their evolutionary paths and end-products. Aims. To enable higher versatility and precision of the complete UV to optical range, we improve our NLTE atmosphere and spectrum synthesis code FASTWIND… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.02310v1-abstract-full').style.display = 'inline'; document.getElementById('2011.02310v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.02310v1-abstract-full" style="display: none;"> Context. Obtaining precise stellar and wind properties and abundance patterns of massive stars is crucial to understanding their nature and interactions with their environments, as well as to constrain their evolutionary paths and end-products. Aims. To enable higher versatility and precision of the complete UV to optical range, we improve our NLTE atmosphere and spectrum synthesis code FASTWIND. We also aim to obtain an advanced description of X-ray emission from wind-embedded shocks. Methods. We include a detailed comoving frame radiative transfer for the essential frequency range, but still apply methods that enable low turnaround times. Results. In most cases, our new results agree excellently with those from the alternative code CMFGEN, both regarding the total radiative acceleration, strategic optical lines, and the UV-range. The agreement regarding NIII4634-4640-4642 has improved, though there are still certain discrepancies, mostly related to line overlap effects in the extreme ultraviolet. In the UV range of our coolest models, we find differences in the predicted depression of the pseudo-continuum, most pronounced around Ly_alpha. The comparison between our new and previous FASTWIND version reveals an almost perfect agreement, except for NV 4603-4619. Using an improved, depth-dependent description for the filling factors of hot, X-ray emitting material, we confirm previous analytic scaling relations with our numerical models. Conclusions. We warn against uncritically relying on transitions, which are strongly affected by direct or indirect line-overlap effects. The predicted UV-continuum depression for the coolest grid-models needs to be checked, both observationally, and regarding the underlying atomic data. Wind lines from "super-ionized" ions such as OVI can, in principle, be used to constrain the distribution of wind-embedded shocks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.02310v1-abstract-full').style.display = 'none'; document.getElementById('2011.02310v1-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, 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">This paper is dedicated to the late Adi Pauldrach, who left us much too early</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astronomy & Astrophysics (2020) 642, A172 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.05136">arXiv:2009.05136</a> <span> [<a href="https://arxiv.org/pdf/2009.05136">pdf</a>, <a href="https://arxiv.org/format/2009.05136">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/staa2801">10.1093/mnras/staa2801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The R136 star cluster dissected with Hubble Space Telescope/STIS. II. Physical properties of the most massive stars in R136 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">Joachim M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">Paul A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero-Nieves%2C+S+M">Saida M. Caballero-Nieves</a>, <a href="/search/astro-ph?searchtype=author&query=Schneider%2C+F+R+N">Fabian R. N. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Simon-Diaz%2C+S">Sergio Simon-Diaz</a>, <a href="/search/astro-ph?searchtype=author&query=Brands%2C+S+A">Sarah A. Brands</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">Alex de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=Graefener%2C+G">Goetz Graefener</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">Artemio Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">Daniel J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Apellaniz%2C+J+M">Jesus Maiz Apellaniz</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">Jorick S. Vink</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="2009.05136v1-abstract-short" style="display: inline;"> We present an optical analysis of 55 members of R136, the central cluster in the Tarantula Nebula of the Large Magellanic Cloud. Our sample was observed with STIS aboard the Hubble Space Telescope, is complete down to about 40\,$M_{\odot}$, and includes 7 very massive stars with masses over 100\,$M_{\odot}$. We performed a spectroscopic analysis to derive their physical properties. Using evolution… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.05136v1-abstract-full').style.display = 'inline'; document.getElementById('2009.05136v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.05136v1-abstract-full" style="display: none;"> We present an optical analysis of 55 members of R136, the central cluster in the Tarantula Nebula of the Large Magellanic Cloud. Our sample was observed with STIS aboard the Hubble Space Telescope, is complete down to about 40\,$M_{\odot}$, and includes 7 very massive stars with masses over 100\,$M_{\odot}$. We performed a spectroscopic analysis to derive their physical properties. Using evolutionary models we find that the initial mass function (IMF) of massive stars in R136 is suggestive of being top-heavy with a power-law exponent $纬\approx 2 \pm 0.3$, but steeper exponents cannot be excluded. The age of R136 lies between 1 and 2\,Myr with a median age of around 1.6\,Myr. Stars more luminous than $\log L/L_{\odot} = 6.3$ are helium enriched and their evolution is dominated by mass loss, but rotational mixing or some other form of mixing could be still required to explain the helium composition at the surface. Stars more massive than 40\,$M_{\odot}$ have larger spectroscopic than evolutionary masses. The slope of the wind-luminosity relation assuming unclumped stellar winds is $2.41\pm0.13$ which is steeper than usually obtained ($\sim 1.8$). The ionising ($\log Q_0\,[{\rm ph/s}] = 51.4$) and mechanical ($\log L_{\rm SW}\,[{\rm erg/s}] = 39.1$) output of R136 is dominated by the most massive stars ($>100\,M_{\odot}$). R136 contributes around a quarter of the ionising flux and around a fifth of the mechanical feedback to the overall budget of the Tarantula Nebula. For a census of massive stars of the Tarantula Nebula region we combined our results with the VLT-FLAMES Tarantula Survey plus other spectroscopic studies. We observe a lack of evolved Wolf-Rayet stars and luminous blue and red supergiants. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.05136v1-abstract-full').style.display = 'none'; document.getElementById('2009.05136v1-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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 for publication in MNRAS, 21 pages, 14 figures, 2 tables plus 33 pages of supplementary material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.06066">arXiv:2008.06066</a> <span> [<a href="https://arxiv.org/pdf/2008.06066">pdf</a>, <a href="https://arxiv.org/format/2008.06066">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/10.1051/0004-6361/202038384">10.1051/0004-6361/202038384 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars II. A grid of O-type stars in the Galaxy and the Magellanic Clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bj%C3%B6rklund%2C+R">R. Bj枚rklund</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2008.06066v1-abstract-short" style="display: inline;"> Reliable predictions of mass-loss rates are important for massive-star evolution computations. We aim to provide predictions for mass-loss rates and wind-momentum rates of O-type stars, carefully studying the behaviour of these winds as functions of stellar parameters like luminosity and metallicity. We use newly developed steady-state models of radiation-driven winds to compute the global propert… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.06066v1-abstract-full').style.display = 'inline'; document.getElementById('2008.06066v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.06066v1-abstract-full" style="display: none;"> Reliable predictions of mass-loss rates are important for massive-star evolution computations. We aim to provide predictions for mass-loss rates and wind-momentum rates of O-type stars, carefully studying the behaviour of these winds as functions of stellar parameters like luminosity and metallicity. We use newly developed steady-state models of radiation-driven winds to compute the global properties of a grid of O-stars. The self-consistent models are calculated by means of an iterative solution to the equation of motion using full NLTE radiative transfer in the co-moving frame to compute the radiative acceleration. In order to study winds in different galactic environments, the grid covers main-sequence stars, giants and supergiants in the Galaxy and both Magellanic Clouds. We find a strong dependence of mass-loss on both luminosity and metallicity. Mean values across the grid are $\dot{M}\sim L_{\ast}^{2.2}$ and $\dot{M}\sim Z_{\ast}^{0.95}$, however we also find a somewhat stronger dependence on metallicity for lower luminosities. Similarly, the mass loss-luminosity relation is somewhat steeper for the SMC than for the Galaxy. In addition, the computed rates are systematically lower (by a factor 2 and more) than those commonly used in stellar-evolution calculations. Overall, our results agree well with observations in the Galaxy that account properly for wind-clumping, with empirical $\dot{M}$ vs. $Z_\ast$ scaling relations, and with observations of O-dwarfs in the SMC. Our results provide simple fit relations for mass-loss rates and wind momenta of massive O-stars stars as functions of luminosity and metallicity, valid in the range $T_{\rm eff} = 28000 - 45000$\,K. Due to the systematically lower $\dot{M}$, our new models suggest that new rates might be needed in evolution simulations of massive stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.06066v1-abstract-full').style.display = 'none'; document.getElementById('2008.06066v1-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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 for publication in A&A. 16 pages, 13 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 648, A36 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.09008">arXiv:2003.09008</a> <span> [<a href="https://arxiv.org/pdf/2003.09008">pdf</a>, <a href="https://arxiv.org/format/2003.09008">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/10.1051/0004-6361/201937341">10.1051/0004-6361/201937341 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spectroscopic patch model for massive stars using PHOEBE II and FASTWIND </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">Michael Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">Hugues Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Conroy%2C+K+E">Kyle E. Conroy</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">Jon Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Pr%C5%A1a%2C+A">Andrej Pr拧a</a>, <a href="/search/astro-ph?searchtype=author&query=Kochoska%2C+A">Angela Kochoska</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</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="2003.09008v1-abstract-short" style="display: inline;"> Massive stars play an important role in the mechanical and chemical evolution of galaxies. Understanding the internal processes of these stars is vital to our understanding of their evolution and eventual end products. Deformations from spherical geometry are common for massive stars; however, the tools that are currently available for the study of these systems are almost exclusively one-dimensio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.09008v1-abstract-full').style.display = 'inline'; document.getElementById('2003.09008v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.09008v1-abstract-full" style="display: none;"> Massive stars play an important role in the mechanical and chemical evolution of galaxies. Understanding the internal processes of these stars is vital to our understanding of their evolution and eventual end products. Deformations from spherical geometry are common for massive stars; however, the tools that are currently available for the study of these systems are almost exclusively one-dimensional. We present a new spectroscopic analysis tool tailored for massive stars that deviate from spherical symmetry. This code (entitled SPAMMS) is a spectroscopic patch model that takes the three-dimensional surface geometry of the system into account to produce spectral profiles at given phases and orientations. In using the Wilson-Devinney-like code PHOEBE in combination with the non local thermodynamic equilibrium (NLTE) radiative transfer code FASTWIND, we created a three-dimensional mesh that represents the surface geometry of our system and we assigned FASTWIND emergent intensity line profiles to each mesh triangle, which take the local parameters such as temperature, surface gravity, and radius into account. These line profiles were then integrated across the visible surface, where their flux contribution and radial velocity are taken into account, thus returning a final line profile for the visible surface of the system at a given phase. We demonstrate that SPAMMS can accurately reproduce the morphology of observed spectral line profiles for overcontact systems. Additionally, we show how line profiles of rapidly-rotating single stars differ when taking rotational distortion into account, and the effects that these can have on the determined parameters. Finally, we demonstrate the code's ability to reproduce the Rossiter-Mclaughlin and Struve-Sahade effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.09008v1-abstract-full').style.display = 'none'; document.getElementById('2003.09008v1-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">10 pages, 10 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/2002.12061">arXiv:2002.12061</a> <span> [<a href="https://arxiv.org/pdf/2002.12061">pdf</a>, <a href="https://arxiv.org/format/2002.12061">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/10.1051/0004-6361/201937098">10.1051/0004-6361/201937098 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A search for strong magnetic fields in massive and very massive stars in the Magellanic Clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">S. Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Naze%2C+Y">Y. Naze</a>, <a href="/search/astro-ph?searchtype=author&query=Grunhut%2C+J+H">J. H. Grunhut</a>, <a href="/search/astro-ph?searchtype=author&query=Shultz%2C+M+E">M. E. Shultz</a>, <a href="/search/astro-ph?searchtype=author&query=Asher%2C+D+J">D. J. Asher</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=David-Uraz%2C+A">A. David-Uraz</a>, <a href="/search/astro-ph?searchtype=author&query=Howarth%2C+I+D">I. D. Howarth</a>, <a href="/search/astro-ph?searchtype=author&query=Morrell%2C+N">N. Morrell</a>, <a href="/search/astro-ph?searchtype=author&query=Munoz%2C+M+S">M. S. Munoz</a>, <a href="/search/astro-ph?searchtype=author&query=Neiner%2C+C">C. Neiner</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Szymanski%2C+M+K">M. K. Szymanski</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</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="2002.12061v1-abstract-short" style="display: inline;"> Despite their rarity, massive stars dominate the ecology of galaxies via their strong, radiatively-driven winds throughout their lives and as supernovae in their deaths. However, their evolution and subsequent impact on their environment can be significantly affected by the presence of a magnetic field. While recent studies indicate that about 7% of OB stars in the Milky Way host strong, stable, o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.12061v1-abstract-full').style.display = 'inline'; document.getElementById('2002.12061v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.12061v1-abstract-full" style="display: none;"> Despite their rarity, massive stars dominate the ecology of galaxies via their strong, radiatively-driven winds throughout their lives and as supernovae in their deaths. However, their evolution and subsequent impact on their environment can be significantly affected by the presence of a magnetic field. While recent studies indicate that about 7% of OB stars in the Milky Way host strong, stable, organised (fossil) magnetic fields at their surfaces, little is known about the fields of very massive stars, nor the magnetic properties of stars outside our Galaxy. We aim to continue searching for strong magnetic fields in a diverse set of massive and very massive stars (VMS) in the Large and Small Magellanic Clouds (LMC/SMC), and we evaluate the overall capability of FORS2 to usefully search for and detect stellar magnetic fields in extra-galactic environments. We have obtained FORS2 spectropolarimetry of a sample of 41 stars, which principally consist of spectral types B, O, Of/WN, WNh, and classical WR stars in the LMC and SMC. Four of our targets are Of?p stars; one of them was just recently discovered. Each spectrum was analysed to infer the longitudinal magnetic field. No magnetic fields were formally detected in our study, although Bayesian statistical considerations suggest that the Of?p star SMC159-2 is magnetic with a dipolar field of the order of 2.4 to 4.4kG. In addition, our first constraints of magnetic fields in VMS provide interesting insights into the formation of the most massive stars in the Universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.12061v1-abstract-full').style.display = 'none'; document.getElementById('2002.12061v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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 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, 635, A163 (15p, 2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.04762">arXiv:2001.04762</a> <span> [<a href="https://arxiv.org/pdf/2001.04762">pdf</a>, <a href="https://arxiv.org/format/2001.04762">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/10.3847/1538-4357/ab6bd0">10.3847/1538-4357/ab6bd0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Towards early-type eclipsing binaries as extragalactic milestones: II. NLTE spectral analysis and stellar parameters of the detached O-type system OGLE-LMC-ECL-06782 in the LMC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Taormina%2C+M">M贸nica Taormina</a>, <a href="/search/astro-ph?searchtype=author&query=Kudritzki%2C+R">Rolf-Peter Kudritzki</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Pilecki%2C+B">Bogumi艂 Pilecki</a>, <a href="/search/astro-ph?searchtype=author&query=Sextl%2C+E">Eva Sextl</a>, <a href="/search/astro-ph?searchtype=author&query=Pietrzy%C5%84ski%2C+G">G. Pietrzy艅ski</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=Gieren%2C+W">Wolfgang Gieren</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="2001.04762v1-abstract-short" style="display: inline;"> We combine the NLTE spectral analysis of the detached O-type eclipsing binary OGLE-LMC-ECL-06782 with the analysis of the radial velocity curve and light curve to measure an independent distance to the LMC. In our spectral analysis we study composite spectra of the system at quadrature and use the information from radial velocity and light curve about stellar gravities, radii and component flux ra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.04762v1-abstract-full').style.display = 'inline'; document.getElementById('2001.04762v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.04762v1-abstract-full" style="display: none;"> We combine the NLTE spectral analysis of the detached O-type eclipsing binary OGLE-LMC-ECL-06782 with the analysis of the radial velocity curve and light curve to measure an independent distance to the LMC. In our spectral analysis we study composite spectra of the system at quadrature and use the information from radial velocity and light curve about stellar gravities, radii and component flux ratio to derive effective temperature, reddening, extinction and intrinsic surface brightness. We obtain a distance modulus to the LMC of m - M = 18.53 +/- 0.04 mag. This value is 0.05 mag larger than the precision distance obtained recently from the analysis of a large sample of detached, long period late spectral type eclipsing binaries but agrees within the margin of the uncertainties. We also determine the surface brightnesses of the system components and find good agreement with the published surface brightness color relationship. A comparison of the observed stellar parameters with the prediction of stellar evolution based on the MESA stellar evolution code shows reasonable agreement, but requires a reduction of the internal angular momentum transport to match the observed rotational velocities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.04762v1-abstract-full').style.display = 'none'; document.getElementById('2001.04762v1-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">18 pages, 16 figures, 3 tables, Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.01451">arXiv:2001.01451</a> <span> [<a href="https://arxiv.org/pdf/2001.01451">pdf</a>, <a href="https://arxiv.org/ps/2001.01451">ps</a>, <a href="https://arxiv.org/format/2001.01451">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/10.1051/0004-6361/201937082">10.1051/0004-6361/201937082 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Tarantula Survey XXXII. Low-luminosity late O-type stars -- classification, main physical parameters, and silicon abundances </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Markova%2C+N">N. Markova</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</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=Ramirez-Agudelo%2C+O+H">O. H. Ramirez-Agudelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</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="2001.01451v1-abstract-short" style="display: inline;"> Analysis of late O-type stars observed in the Large Magellanic Cloud (LMC) by the VLT-FLAMES Tarantula Survey (VFTS) revealed a discrepancy between the physical properties estimated from model-atmosphere analysis and those expected from their morphological classifications. Here we revisit the analysis of 32 of these puzzling objects using new hydrogen-helium-silicon FASTWIND models and a different… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.01451v1-abstract-full').style.display = 'inline'; document.getElementById('2001.01451v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.01451v1-abstract-full" style="display: none;"> Analysis of late O-type stars observed in the Large Magellanic Cloud (LMC) by the VLT-FLAMES Tarantula Survey (VFTS) revealed a discrepancy between the physical properties estimated from model-atmosphere analysis and those expected from their morphological classifications. Here we revisit the analysis of 32 of these puzzling objects using new hydrogen-helium-silicon FASTWIND models and a different fitting approach to re-evaluate their physical properties. Our new analysis confirms that these stars indeed have properties that are typical of late O-type dwarfs. We also present the first estimates of silicon abundances for O-type stars in the 30 Dor clusters NGC 2060 and NGC 2070, with a weighted mean abundance for our sample of 7.05 +/- 0.03. Our values are about 0.20 dex lower than those previously derived for B-type stars in the LMC clusters N 11 and NGC 2004 using TLUSTY models. Various possibilities (e.g. differences in the analysis methods, effects of microturbulence, and real differences between stars in different clusters) were considered to account for these results. We also used our grid of FASTWIND models to reassess the impact of using the Galactic classification criteria for late O-type stars in the LMC by scrutinising their sensitivity to different stellar properties. At the cool edge of the O star regime the HeII 4686/HeI 4713 ratio used to assign luminosity class for Galactic stars can mimic giants or bright giants in the LMC, even for objects with high gravities (log_g > 4.0 dex). We argue that this line ratio is not a reliable luminosity diagnostic for late O-type stars in the LMC, and that the SiIV 4989/HeI4026 ratio is more robust for these types. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.01451v1-abstract-full').style.display = 'none'; document.getElementById('2001.01451v1-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">18 pages, 10 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 634, A16 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.09826">arXiv:1912.09826</a> <span> [<a href="https://arxiv.org/pdf/1912.09826">pdf</a>, <a href="https://arxiv.org/format/1912.09826">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/10.1051/0004-6361/201937375">10.1051/0004-6361/201937375 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Properties of OB star-black hole systems derived from detailed binary evolution models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BCrmann%2C+C">C. Sch眉rmann</a>, <a href="/search/astro-ph?searchtype=author&query=Stoll%2C+K">K. Stoll</a>, <a href="/search/astro-ph?searchtype=author&query=Marchant%2C+P">P. Marchant</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">L. Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">S. E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Quast%2C+M">M. Quast</a>, <a href="/search/astro-ph?searchtype=author&query=Riedel%2C+W">W. Riedel</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+P">P. Schneider</a>, <a href="/search/astro-ph?searchtype=author&query=Schootemeijer%2C+A">A. Schootemeijer</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+C">Chen Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Almeida%2C+L+A">L. A. Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Bodensteiner%2C+J">J. Bodensteiner</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Clark%2C+S">S. Clark</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Dufton%2C+P">P. Dufton</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Fossati%2C+L">L. Fossati</a>, <a href="/search/astro-ph?searchtype=author&query=Gr%C3%A4fener%2C+G">G. Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Grassitelli%2C+L">L. Grassitelli</a>, <a href="/search/astro-ph?searchtype=author&query=Grin%2C+N">N. Grin</a> , et al. (16 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="1912.09826v2-abstract-short" style="display: inline;"> The recent gravitational wave measurements have demonstrated the existence of stellar mass black hole binaries. It is essential for our understanding of massive star evolution to identify the contribution of binary evolution to the formation of double black holes. A promising way to progress is investigating the progenitors of double black hole systems and comparing predictions with local massive… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.09826v2-abstract-full').style.display = 'inline'; document.getElementById('1912.09826v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.09826v2-abstract-full" style="display: none;"> The recent gravitational wave measurements have demonstrated the existence of stellar mass black hole binaries. It is essential for our understanding of massive star evolution to identify the contribution of binary evolution to the formation of double black holes. A promising way to progress is investigating the progenitors of double black hole systems and comparing predictions with local massive star samples such as the population in 30 Doradus in the Large Magellanic Cloud (LMC). Methods. To this purpose, we analyse a large grid of detailed binary evolution models at LMC metallicity with initial primary masses between 10 and 40 Msun, and identify which model systems potentially evolve into a binary consisting of a black hole and a massive main sequence star. We then derive the observable properties of such systems, as well as peculiarities of the OB star component. We find that about 3% of the LMC late O and early B stars in binaries are expected to possess a black hole companion, when assuming stars with a final helium core mass above 6.6 M to form black holes. While the vast majority of them may be X-ray quiet, our models suggest that these may be identified in spectroscopic binaries, either by large amplitude radial velocity variations ( > 50 km s ) and simultaneous nitrogen surface enrichment, or through a moderate radial velocity ( > 10 km/s ) and simultaneously rapid rotation of the OB star. The predicted mass ratios are such that main sequence companions could be excluded in most cases. A comparison to the observed OB+WR binaries in the LMC, Be/X-ray binaries, and known massive BH binaries supports our conclusion. We expect spectroscopic observations to be able to test key assumptions in our models, with important implications for massive star evolution in general, and for the formation of double-black hole mergers in particular. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.09826v2-abstract-full').style.display = 'none'; document.getElementById('1912.09826v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 14 figures, Astronomy and Astrophysics, in press</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 638, A39 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.13379">arXiv:1910.13379</a> <span> [<a href="https://arxiv.org/pdf/1910.13379">pdf</a>, <a href="https://arxiv.org/ps/1910.13379">ps</a>, <a href="https://arxiv.org/format/1910.13379">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/10.1051/0004-6361/201936584">10.1051/0004-6361/201936584 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A 3D short-characteristics method for continuum and line scattering problems in the winds of hot stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hennicker%2C+L">L. Hennicker</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Kee%2C+N+D">N. D. Kee</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</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="1910.13379v1-abstract-short" style="display: inline;"> Context: Knowledge about hot, massive stars is usually inferred from quantitative spectroscopy. To analyse non-spherical phenomena, the existing 1D codes must be extended to higher dimensions, and corresponding tools need to be developed. Aims: We present a 3D radiative transfer code that is capable of calculating continuum and line scattering problems in the winds of hot stars. By considering sph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.13379v1-abstract-full').style.display = 'inline'; document.getElementById('1910.13379v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.13379v1-abstract-full" style="display: none;"> Context: Knowledge about hot, massive stars is usually inferred from quantitative spectroscopy. To analyse non-spherical phenomena, the existing 1D codes must be extended to higher dimensions, and corresponding tools need to be developed. Aims: We present a 3D radiative transfer code that is capable of calculating continuum and line scattering problems in the winds of hot stars. By considering spherically symmetric test models, we discuss potential error sources, and indicate advantages and disadvantages by comparing different solution methods. Further, we analyse the UV resonance line formation in the winds of rapidly rotating O stars. Methods: We consider both a (simplified) continuum model including scattering and thermal sources, and a UV resonance line transition approximated by a two-level-atom. We applied the short-characteristics (SC) method, using linear or monotonic B茅zier interpolations, to solve the equation of radiative transfer on a non-uniform Cartesian grid. To calculate scattering dominated problems, our solution method is supplemented by an accelerated $螞$-iteration scheme. Results: For the spherical test models, the mean relative error of the source function is on the $5-20\,\%$ level, depending on the applied interpolation technique and the complexity of the considered model. All calculated line profiles are in excellent agreement with corresponding 1D solutions. The predicted line profiles from fast rotating stars show a distinct behaviour as a function of rotational speed and inclination. This behaviour is tightly coupled to the wind structure and the description of gravity darkening and stellar surface distortion. Conclusions: Our SC methods are ready to be used for quantitative analyses of UV resonance line profiles. When calculating optically thick continua, both SC methods give reliable results, in contrast to the alternative finite-volume method. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.13379v1-abstract-full').style.display = 'none'; document.getElementById('1910.13379v1-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 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 633, A16 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.06586">arXiv:1910.06586</a> <span> [<a href="https://arxiv.org/pdf/1910.06586">pdf</a>, <a href="https://arxiv.org/ps/1910.06586">ps</a>, <a href="https://arxiv.org/format/1910.06586">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/10.1051/0004-6361/201936580">10.1051/0004-6361/201936580 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars. I. Method and first results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Bj%C3%B6rklund%2C+R">R. Bj枚rklund</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.06586v1-abstract-short" style="display: inline;"> [Abridged] Context: Radiation-driven mass loss plays a key role in the life-cycles of massive stars. However, basic predictions of such mass loss still suffer from significant quantitative uncertainties. Aims: We develop new radiation-driven, steady-state wind models for massive stars with hot surfaces, suitable for quantitative predictions of global parameters like mass-loss and wind-momentum rat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.06586v1-abstract-full').style.display = 'inline'; document.getElementById('1910.06586v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.06586v1-abstract-full" style="display: none;"> [Abridged] Context: Radiation-driven mass loss plays a key role in the life-cycles of massive stars. However, basic predictions of such mass loss still suffer from significant quantitative uncertainties. Aims: We develop new radiation-driven, steady-state wind models for massive stars with hot surfaces, suitable for quantitative predictions of global parameters like mass-loss and wind-momentum rates. Methods: The simulations presented here are based on a self-consistent, iterative grid-solution to the spherically symmetric, steady-state equation of motion, using full NLTE radiative transfer solutions in the co-moving frame to derive the radiative acceleration. We do not rely on any distribution functions or parametrization for computation of the line force responsible for the wind driving. Results: In this first paper, we present models representing two prototypical O-stars in the Galaxy, one with a higher stellar mass M/Msun=59 and luminosity log10(L/Lsun)= 5.87 and one with a lower M/Msun= 27 and log10(L/Lsun)= 5.1. For these simulations, basic predictions for global mass-loss rates and velocity laws are given, and the influence from additional parameters like wind clumping and microturbulent speeds discussed. A key result is that our mass-loss rates are significantly lower than those predicted by the mass-loss recipes normally included in models of massive-star evolution. Conclusions: Our results support previous suggestions that Galactic O-star mass-loss rates may be overestimated in present-day stellar evolution models, and that new rates thus might be needed. Indeed, future papers in this series will incorporate our new models into such simulations of stellar evolution, extending the very first simulations presented here toward larger grids covering a range of metallicities, B supergiants across the bistability jump, and possibly also Wolf-Rayet stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.06586v1-abstract-full').style.display = 'none'; document.getElementById('1910.06586v1-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 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">13 pages, 10 figures, accepted for publication in Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.05792">arXiv:1910.05792</a> <span> [<a href="https://arxiv.org/pdf/1910.05792">pdf</a>, <a href="https://arxiv.org/format/1910.05792">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/stz2904">10.1093/mnras/stz2904 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modelling the photometric variability of magnetic massive stars with the Analytical Dynamical Magnetosphere model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Munoz%2C+M+S">M. S. Munoz</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Y. Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">S. Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Szyma%C5%84ski%2C+M+K">M. K. Szyma艅ski</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="1910.05792v1-abstract-short" style="display: inline;"> In this paper, we investigate the photometric variability of magnetic O-type stars. Such stars possess oblique, predominantly dipolar magnetic fields that confine their winds roughly axisymmetrically about the magnetic equator, thus forming a magnetosphere. We interpret their photometric variability as phase-dependent magnetospheric occultations. For massive star winds dominated by electron scatte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.05792v1-abstract-full').style.display = 'inline'; document.getElementById('1910.05792v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.05792v1-abstract-full" style="display: none;"> In this paper, we investigate the photometric variability of magnetic O-type stars. Such stars possess oblique, predominantly dipolar magnetic fields that confine their winds roughly axisymmetrically about the magnetic equator, thus forming a magnetosphere. We interpret their photometric variability as phase-dependent magnetospheric occultations. For massive star winds dominated by electron scattering opacity in the optical and NIR, we can compute synthetic light curves from simply knowing the magnetosphere's mass density distribution. We exploit the newly-developed Analytical Dynamical Magnetosphere model (ADM) in order to obtain the predicted circumstellar density structures of magnetic O-type stars. The simplicity in our light curve synthesis model allows us to readily conduct a parameter space study. For validation purposes, we first apply our algorithm to HD 191612, the prototypical Of?p star. Next, we attempt to model the photometric variability of the Of?p-type stars identified in the Magellanic Clouds using OGLE photometry. We evaluate the compatibility of the ADM predictions with the observed photometric variations, and discuss the magnetic field properties that are implied by our modelling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.05792v1-abstract-full').style.display = 'none'; document.getElementById('1910.05792v1-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 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">17 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 492, 1199-1213 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.01066">arXiv:1906.01066</a> <span> [<a href="https://arxiv.org/pdf/1906.01066">pdf</a>, <a href="https://arxiv.org/format/1906.01066">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/10.3847/1538-4357/ab24d4">10.3847/1538-4357/ab24d4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Clues on the Origin and Evolution of Massive Contact Binaries: Atmosphere Analysis of VFTS 352 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Abdul-Masih%2C+M">Michael Abdul-Masih</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">Hugues Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J">Jon Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Mahy%2C+L">Laurent Mahy</a>, <a href="/search/astro-ph?searchtype=author&query=Menon%2C+A">Athira Menon</a>, <a href="/search/astro-ph?searchtype=author&query=Almeida%2C+L+A">Leonardo A. Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=De+Koter%2C+A">Alex De Koter</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">Selma E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Justham%2C+S">Stephen Justham</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Shenar%2C+T">Tomer Shenar</a>, <a href="/search/astro-ph?searchtype=author&query=Tramper%2C+F">Frank Tramper</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="1906.01066v1-abstract-short" style="display: inline;"> The massive O4.5 V + O5.5 V binary VFTS 352 in the Tarantula nebula is one of the shortest-period and most massive overcontact binaries known. Recent theoretical studies indicate that some of these systems could ultimately lead to the formation of gravitational waves via black hole binary mergers through the chemically homogeneous evolution pathway. By analyzing ultraviolet-optical phase-resolved… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.01066v1-abstract-full').style.display = 'inline'; document.getElementById('1906.01066v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.01066v1-abstract-full" style="display: none;"> The massive O4.5 V + O5.5 V binary VFTS 352 in the Tarantula nebula is one of the shortest-period and most massive overcontact binaries known. Recent theoretical studies indicate that some of these systems could ultimately lead to the formation of gravitational waves via black hole binary mergers through the chemically homogeneous evolution pathway. By analyzing ultraviolet-optical phase-resolved spectroscopic data, we aim to constrain atmospheric and wind properties that could be later used to confront theoretical predictions from binary evolution. In particular, surface abundances are powerful diagnostics of the evolutionary status, mass transfer and the internal mixing processes. From a set of 32 VLT/FLAMES visual and 8 HST/COS ultraviolet spectra, we used spectral disentangling to separate the primary and secondary components. Using a genetic algorithm wrapped around the NLTE model atmosphere and spectral synthesis code FASTWIND, we perform an 11-parameter optimization to derive the atmospheric and wind parameters of both components, including the surface abundances of He, C, N, O and Si. We find that both components are hotter than expected compared to single-star evolutionary models indicating that additional mixing processes may be at play. However the derived chemical abundances do not show significant indications of mixing when adopting baseline values typical for the system environment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.01066v1-abstract-full').style.display = 'none'; document.getElementById('1906.01066v1-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">24 pages, 4 tables, 12 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.09816">arXiv:1807.09816</a> <span> [<a href="https://arxiv.org/pdf/1807.09816">pdf</a>, <a href="https://arxiv.org/format/1807.09816">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/10.1126/science.aat7032">10.1126/science.aat7032 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Response to comment on "An excess of massive stars in the local 30 Doradus starburst" </p> <p class="authors"> <span class="search-hit">Authors:</span> <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=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=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=Gr%C3%A4fener%2C+G">G. Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Ram%C3%ADrez-Agudelo%2C+O+H">O. H. Ram铆rez-Agudelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sab%C3%ADn-Sanjuli%C3%A1n%2C+C">C. Sab铆n-Sanjuli谩n</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=Tramper%2C+F">F. Tramper</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">S. E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Gieles%2C+M">M. Gieles</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%A9nault-Brunet%2C+V">V. H茅nault-Brunet</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Izzard%2C+R+G">R. G. Izzard</a>, <a href="/search/astro-ph?searchtype=author&query=Kalari%2C+V">V. Kalari</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Markova%2C+N">N. Markova</a> , et al. (7 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="1807.09816v1-abstract-short" style="display: inline;"> Farr and Mandel reanalyse our data, finding initial-mass-function slopes for high mass stars in 30 Doradus that agree with our results. However, their reanalysis appears to underpredict the observed number of massive stars. Their technique results in more precise slopes than in our work, strengthening our conclusion that there is an excess of massive stars above $30\,\mathrm{M}_\odot$ in 30 Doradu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09816v1-abstract-full').style.display = 'inline'; document.getElementById('1807.09816v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.09816v1-abstract-full" style="display: none;"> Farr and Mandel reanalyse our data, finding initial-mass-function slopes for high mass stars in 30 Doradus that agree with our results. However, their reanalysis appears to underpredict the observed number of massive stars. Their technique results in more precise slopes than in our work, strengthening our conclusion that there is an excess of massive stars above $30\,\mathrm{M}_\odot$ in 30 Doradus. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09816v1-abstract-full').style.display = 'none'; document.getElementById('1807.09816v1-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, 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">Authors' version of a response to a technical comment published in Science; 8 pages, 1 figure</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.08155">arXiv:1806.08155</a> <span> [<a href="https://arxiv.org/pdf/1806.08155">pdf</a>, <a href="https://arxiv.org/format/1806.08155">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/10.1051/0004-6361/201731858">10.1051/0004-6361/201731858 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> 3D radiative transfer: Continuum and line scattering in non-spherical winds from OB stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hennicker%2C+L">L. Hennicker</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Kee%2C+N+D">N. D. Kee</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</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="1806.08155v1-abstract-short" style="display: inline;"> Context: State of the art quantitative spectroscopy of OB-stars compares synthetic spectra (calculated by means of 1D, spherically symmetric computer codes) with observations. Certain stellar atmospheres, however, show strong deviations from spherical symmetry, and need to be treated in 3D. Aims: We present a newly developed 3D radiative transfer code, tailored to the solution of the radiation fie… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.08155v1-abstract-full').style.display = 'inline'; document.getElementById('1806.08155v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.08155v1-abstract-full" style="display: none;"> Context: State of the art quantitative spectroscopy of OB-stars compares synthetic spectra (calculated by means of 1D, spherically symmetric computer codes) with observations. Certain stellar atmospheres, however, show strong deviations from spherical symmetry, and need to be treated in 3D. Aims: We present a newly developed 3D radiative transfer code, tailored to the solution of the radiation field in rapidly expanding stellar atmospheres. We apply our code to the continuum transfer in wind-ablation models, and to the UV resonance line formation in magnetic winds. Methods: We have used a 3D finite-volume method for the solution of the equation of radiative transfer, to study continuum- and line-scattering problems. Convergence has been accelerated by a non-local approximate Lambda-iteration scheme. Particular emphasis has been put on careful (spherically symmetric) test cases. Results: Typical errors of the source functions, when compared to 1D solutions, are of the order of 10-20 %, and increase for optically thick continua. In circumstellar discs, the radiation temperatures in the (optically thin) transition region from wind to disc are quite similar to corresponding values in the wind. For MHD simulations of dynamical magnetospheres, the line profiles, calculated with our 3D code, agree well with previous solutions using a 3D-SEI method. When compared with profiles resulting from the `analytic dynamical magnetosphere' (ADM) model, significant differences become apparent. Conclusions: Due to similar radiation temperatures in the wind and the transition region to the disc, the same line-strength distribution can be applied within radiation hydrodynamic calculations for circumstellar discs in `accreting high-mass stars'. To properly describe the UV line formation in dynamical magnetospheres, the ADM model needs to be further developed, at least in a large part of the outer wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.08155v1-abstract-full').style.display = 'none'; document.getElementById('1806.08155v1-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 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 616, A140 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.11010">arXiv:1805.11010</a> <span> [<a href="https://arxiv.org/pdf/1805.11010">pdf</a>, <a href="https://arxiv.org/ps/1805.11010">ps</a>, <a href="https://arxiv.org/format/1805.11010">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/10.1051/0004-6361/201832993">10.1051/0004-6361/201832993 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atmospheric NLTE-models for the spectroscopic analysis of blue stars with winds. IV. Porosity in physical and velocity space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</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="1805.11010v1-abstract-short" style="display: inline;"> [Abridged] Clumping in the radiation-driven winds of hot, massive stars affects the derivation of synthetic observables across the electromagnetic spectrum. We implement a formalism for treating wind clumping - in particular the light-leakage effects associated with a medium that is porous in physical and velocity space - into the global (photosphere+wind) NLTE model atmosphere code FASTWIND. We a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.11010v1-abstract-full').style.display = 'inline'; document.getElementById('1805.11010v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.11010v1-abstract-full" style="display: none;"> [Abridged] Clumping in the radiation-driven winds of hot, massive stars affects the derivation of synthetic observables across the electromagnetic spectrum. We implement a formalism for treating wind clumping - in particular the light-leakage effects associated with a medium that is porous in physical and velocity space - into the global (photosphere+wind) NLTE model atmosphere code FASTWIND. We assume a stochastic, two-component wind consisting of a mixture of optically thick and thin clumps embedded in a rarefied inter-clump medium. We account fully for the reductions in opacity associated with porosity in physical and velocity-space, and for the well-known effect that opacities depending on rho^2 are higher in clumpy winds than in smooth ones of equal mass-loss rate. By formulating our method in terms of suitable mean and effective opacities for the clumpy wind, we are able to compute models with the same speed (~15 min. on a modern laptop) as in previous code-generations. Some first, generic results of the new models include: i) Confirming earlier results that velocity-space porosity is critical for analysis of UV wind lines in O-stars; ii) for the optical Halpha line, optically thick clumping effects are small for O-stars, but potentially very important for late B and A-supergiants; iii) spatial porosity is a marginal effect for absorption of high-energy X-rays in O-stars, as long as the mean-free path between clumps are kept at realistic values; iv) porosity is negligible at typical O-star radio-photosphere radii; v) regarding the wind ionization balance, a general trend is that increased rates of recombination in simulations with optically thin clumps lead to overall lower degrees of ionization than in corresponding smooth models, but that this effect now is counteracted by the increased levels of light-leakage associated with porosity in physical and velocity space. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.11010v1-abstract-full').style.display = 'none'; document.getElementById('1805.11010v1-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 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, 5 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/1803.03410">arXiv:1803.03410</a> <span> [<a href="https://arxiv.org/pdf/1803.03410">pdf</a>, <a href="https://arxiv.org/ps/1803.03410">ps</a>, <a href="https://arxiv.org/format/1803.03410">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/10.1051/0004-6361/201731361">10.1051/0004-6361/201731361 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spectroscopic and physical parameters of Galactic O-type stars. III. Mass discrepancy and rotational mixing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Markova%2C+N">Nevena Markova</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">Norbert Langer</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.03410v1-abstract-short" style="display: inline;"> Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution and atmosphere models. We used a sample of 53 objects with spectral types from O3 to O9.7. For 30 of these, we determined the main photospheric and wind paramete… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.03410v1-abstract-full').style.display = 'inline'; document.getElementById('1803.03410v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.03410v1-abstract-full" style="display: none;"> Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution and atmosphere models. We used a sample of 53 objects with spectral types from O3 to O9.7. For 30 of these, we determined the main photospheric and wind parameters, using optical spectroscopy and applying the FASTWIND code. For the remaining objects, literature data, obtained by means of the CMFGEN code, were used instead. The properties of our sample were compared to published predictions based on two grids evolution models that include rotationally induced mixing. Within each luminosity class, we find a close correlation of N surface abundance and luminosity, and a stronger N enrichment in more massive and evolved O stars. Additionally, a correlation of the surface nitrogen and helium abundances is observed. The large number of nitrogen-enriched stars above ~30 solar masses argues for rotationally induced mixing as the most likely explanation. However, none of the considered models can match the observed trends correctly, especially in the high mass regime. We confirm mass discrepancy for objects in the low mass O-star regime. We conclude that the rotationally induced mixing of helium to the stellar surface is too strong in some of the models. We also suggest that present inadequacies of the models to represent the N enrichment in more massive stars with relatively slow rotation might be related to problematic efficiencies of rotational mixing. We are left with a picture in which invoking binarity and magnetic fields is required to achieve a more complete agreement of the observed surface properties of a population of massive main- sequence stars with corresponding evolutionary models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.03410v1-abstract-full').style.display = 'none'; document.getElementById('1803.03410v1-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 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 16 figures, 3 appendices</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 613, A12 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.06152">arXiv:1801.06152</a> <span> [<a href="https://arxiv.org/pdf/1801.06152">pdf</a>, <a href="https://arxiv.org/format/1801.06152">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> The Of?p stars of the Magellanic Clouds: Are they strongly magnetic? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Munoz%2C+M">Melissa Munoz</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G">Gregg Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Naz%C3%A9%2C+Y">Ya毛l Naz茅</a>, <a href="/search/astro-ph?searchtype=author&query=Bagnulo%2C+S">Stefano Bagnulo</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1801.06152v1-abstract-short" style="display: inline;"> All known Galactic Of?p stars have been shown to host strong, organized, magnetic fields. Recently, five Of?p stars have been discovered in the Magellanic Clouds. They posses photometric \citep{Naze} and spectroscopic \citep{Walborn} variability compatible with the Oblique Rotator Model (ORM). However, their magnetic fields have yet to be directly detected. We have developed an algorithm allowing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.06152v1-abstract-full').style.display = 'inline'; document.getElementById('1801.06152v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.06152v1-abstract-full" style="display: none;"> All known Galactic Of?p stars have been shown to host strong, organized, magnetic fields. Recently, five Of?p stars have been discovered in the Magellanic Clouds. They posses photometric \citep{Naze} and spectroscopic \citep{Walborn} variability compatible with the Oblique Rotator Model (ORM). However, their magnetic fields have yet to be directly detected. We have developed an algorithm allowing for the synthesis of photometric observables based on the Analytic Dynamical Magnetosphere (ADM) model of \citet{Owocki}. We apply our model to OGLE photometry in order to constrain their magnetic geometries and surface dipole strengths. We predict that the field strengths for some of these candidate extra-Galactic magnetic stars may be within the detection limits of the FORS2 instrument. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.06152v1-abstract-full').style.display = 'none'; document.getElementById('1801.06152v1-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 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 2 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/1801.03107">arXiv:1801.03107</a> <span> [<a href="https://arxiv.org/pdf/1801.03107">pdf</a>, <a href="https://arxiv.org/format/1801.03107">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/10.1126/science.aan0106">10.1126/science.aan0106 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An excess of massive stars in the local 30 Doradus starburst </p> <p class="authors"> <span class="search-hit">Authors:</span> <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=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=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=Gr%C3%A4fener%2C+G">G. Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Ram%C3%ADrez-Agudelo%2C+O+H">O. H. Ram铆rez-Agudelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sab%C3%ADn-Sanjuli%C3%A1n%2C+C">C. Sab铆n-Sanjuli谩n</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=Tramper%2C+F">F. Tramper</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">S. E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Dufton%2C+P+L">P. L. Dufton</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Gieles%2C+M">M. Gieles</a>, <a href="/search/astro-ph?searchtype=author&query=H%C3%A9nault-Brunet%2C+V">V. H茅nault-Brunet</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Izzard%2C+R+G">R. G. Izzard</a>, <a href="/search/astro-ph?searchtype=author&query=Kalari%2C+V">V. Kalari</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Markova%2C+N">N. Markova</a> , et al. (7 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="1801.03107v1-abstract-short" style="display: inline;"> The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analogue of large star-formation events in the distant Universe. We determine the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus based on spectroscopic observations of 247 stars more massive than 15 solar masses ($\mathrm{M}_\odot$). The main episode of massive star formation s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.03107v1-abstract-full').style.display = 'inline'; document.getElementById('1801.03107v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.03107v1-abstract-full" style="display: none;"> The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analogue of large star-formation events in the distant Universe. We determine the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus based on spectroscopic observations of 247 stars more massive than 15 solar masses ($\mathrm{M}_\odot$). The main episode of massive star formation started about $8\,\mathrm{Myr}$ ago and the star-formation rate seems to have declined in the last $1\,\mathrm{Myr}$. The IMF is densely sampled up to $200\,\mathrm{M}_\odot$ and contains $32\pm12\%$ more stars above $30\,\mathrm{M}_\odot$ than predicted by a standard Salpeter IMF. In the mass range $15-200\,\mathrm{M}_\odot$, the IMF power-law exponent is $1.90^{+0.37}_{-0.26}$, shallower than the Salpeter value of 2.35. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.03107v1-abstract-full').style.display = 'none'; document.getElementById('1801.03107v1-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Authors' version of paper published in Science at http://science.sciencemag.org/content/359/6371/69 ; 15 pages main text (3 figures), 47 pages supplementary materials (10 figures, 3 tables)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 359, 69 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1711.10043">arXiv:1711.10043</a> <span> [<a href="https://arxiv.org/pdf/1711.10043">pdf</a>, <a href="https://arxiv.org/format/1711.10043">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/10.1051/0004-6361/201731543">10.1051/0004-6361/201731543 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The IACOB project. V. Spectroscopic parameters of the O-type stars in the modern grid of standards for spectral classification </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Holgado%2C+G">G. Holgado</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=Barb%C3%A1%2C+R+H">R. H. Barb谩</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Negueruela%2C+I">I. Negueruela</a>, <a href="/search/astro-ph?searchtype=author&query=Sab%C3%ADn-Sanjuli%C3%A1n%2C+C">C. Sab铆n-Sanjuli谩n</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="1711.10043v2-abstract-short" style="display: inline;"> The IACOB and OWN surveys are two ambitious complementary observational projects which have made available a large multi-epoch spectroscopic database of optical high resolution spectra of Galactic massive O-type stars. As a first step in the study of the full sample of (more than 350) O stars surveyed by the IACOB/OWN projects, we have performed the quantitative spectroscopic analysis of a subsamp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.10043v2-abstract-full').style.display = 'inline'; document.getElementById('1711.10043v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1711.10043v2-abstract-full" style="display: none;"> The IACOB and OWN surveys are two ambitious complementary observational projects which have made available a large multi-epoch spectroscopic database of optical high resolution spectra of Galactic massive O-type stars. As a first step in the study of the full sample of (more than 350) O stars surveyed by the IACOB/OWN projects, we have performed the quantitative spectroscopic analysis of a subsample of 128 stars included in the modern grid of O-type standards for spectral classification. We use semi-automatized tools to determine the set of spectroscopic parameters that can be obtained from the optical spectrum of O-type stars. We also benefit from the multi-epoch character of the surveys to perform a spectroscopic variability study of the sample, accounting for spectroscopic binarity and variability of the main wind diagnostic lines. We provide a general overview of the stellar and wind parameters of this reference sample, and updated recipes for the SpT\,--\,Teff/log g calibrations for Galactic O-type stars. We evaluate our semi-automatized analysis strategy with $\sim$40 stars from the literature, and find a good agreement. The agreement between the synthetic spectra associated with fastwind best fitting models and the observed spectra is good for most targets, but 46 stars present a particular behavior of the wind diagnostic lines that cannot be reproduced by our grid of spherically symmetric unclumped models. These are potential targets of interest for more detailed investigations of clumpy winds and/or the existence of additional circumstellar components. Last, our variability study has led to the detection of signatures of spectroscopic binarity in 27\% of the stars and small amplitude radial velocity variations in the photospheric lines of another 30\%. Additionally, 31\% of the investigated stars show variability in the wind diagnostic lines. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.10043v2-abstract-full').style.display = 'none'; document.getElementById('1711.10043v2-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 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 November, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 18 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 613, A65 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.07780">arXiv:1710.07780</a> <span> [<a href="https://arxiv.org/pdf/1710.07780">pdf</a>, <a href="https://arxiv.org/format/1710.07780">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/10.1051/0004-6361/201731718">10.1051/0004-6361/201731718 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> 2D wind clumping in hot, massive stars from hydrodynamical line-driven instability simulations using a pseudo-planar approach </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">J. O. Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">S. P. Owocki</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1710.07780v1-abstract-short" style="display: inline;"> Context: Clumping in the radiation-driven winds of hot, massive stars arises naturally due to the strong, intrinsic instability of line-driving (the `LDI'). But LDI wind models have so far mostly been limited to 1D, mainly because of severe computational challenges regarding calculation of the multi-dimensional radiation force. Aims: To simulate and examine the dynamics and multi-dimensional natur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.07780v1-abstract-full').style.display = 'inline'; document.getElementById('1710.07780v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.07780v1-abstract-full" style="display: none;"> Context: Clumping in the radiation-driven winds of hot, massive stars arises naturally due to the strong, intrinsic instability of line-driving (the `LDI'). But LDI wind models have so far mostly been limited to 1D, mainly because of severe computational challenges regarding calculation of the multi-dimensional radiation force. Aims: To simulate and examine the dynamics and multi-dimensional nature of wind structure resulting from the LDI. Methods: We introduce a `pseudo-planar', `box-in-a-wind' method that allows us to efficiently compute the line-force in the radial and lateral directions, and then use this approach to carry out 2D radiation-hydrodynamical simulations of the time-dependent wind. Results: Our 2D simulations show that the LDI first manifests itself by mimicking the typical shell-structure seen in 1D models, but how these shells then quickly break up into complex 2D density and velocity structures, characterized by small-scale density `clumps' embedded in larger regions of fast and rarefied gas. Key results of the simulations are that density-variations in the well-developed wind statistically are quite isotropic and that characteristic length-scales are small; a typical clump size is ~0.01R at 2R, thus resulting also in rather low typical clump-masses ~10^17 g. Overall, our results agree well with the theoretical expectation that the characteristic scale for LDI-generated wind-structure is of order the Sobolev length. We further confirm some earlier results that lateral `filling-in' of radially compressed gas leads to somewhat lower clumping factors in 2D simulations than in comparable 1D models. We conclude by discussing an extension of our method toward rotating LDI wind models that exhibit an intriguing combination of large- and small-scale structure extending down to the wind base. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.07780v1-abstract-full').style.display = 'none'; document.getElementById('1710.07780v1-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 7 figures + 1 Appendix with 1 figure. Recommended 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 611, A17 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.08146">arXiv:1708.08146</a> <span> [<a href="https://arxiv.org/pdf/1708.08146">pdf</a>, <a href="https://arxiv.org/ps/1708.08146">ps</a>, <a href="https://arxiv.org/format/1708.08146">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/10.1051/0004-6361/201731839">10.1051/0004-6361/201731839 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Carbon line formation and spectroscopy in O-type stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Carneiro%2C+L+P">Luiz P. Carneiro</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Hoffmann%2C+T+L">T. L. Hoffmann</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="1708.08146v2-abstract-short" style="display: inline;"> The determination of chemical abundances constitutes a fundamental requirement for obtaining a complete picture of a star. Particularly in massive stars, CNO abundances are of prime interest, due to the nuclear CNO-cycle and various mixing processes which bring these elements to the surface. We aim at enabling a reliable carbon spectroscopy for our unified NLTE atmosphere code FASTWIND. We dev… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.08146v2-abstract-full').style.display = 'inline'; document.getElementById('1708.08146v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.08146v2-abstract-full" style="display: none;"> The determination of chemical abundances constitutes a fundamental requirement for obtaining a complete picture of a star. Particularly in massive stars, CNO abundances are of prime interest, due to the nuclear CNO-cycle and various mixing processes which bring these elements to the surface. We aim at enabling a reliable carbon spectroscopy for our unified NLTE atmosphere code FASTWIND. We develop a new carbon model atom including CII/III/IV/V, and discuss problems related to carbon spectroscopy in O-type stars. We describe different tests to examine the reliability of our implementation, and investigate which mechanisms influence the carbon ionization balance. By comparing with high-resolution spectra from six O-type stars, we check in how far observational constraints can be reproduced by our new carbon line synthesis. Carbon lines are even more sensitive to a variation of temperature, gravity, and mass-loss rate, than hydrogen/helium lines. We are able to reproduce most of the observed lines from our stellar sample, and to estimate those specific carbon abundances which bring the lines from different ions into agreement. For hot dwarfs and supergiants earlier than O7, X-rays from wind-embedded shocks can impact the synthesized line strengths, particularly for CIV, potentially affecting the abundance determination. We have demonstrated our capability to derive realistic carbon abundances by means of FASTWIND, using our recently developed model atom. We found that complex effects can have a strong influence on the carbon ionization balance in hot stars. For a further understanding, the UV range needs to be explored as well. By means of detailed nitrogen and oxygen model atoms available to use, we will be able to perform a complete CNO abundance analysis for larger samples of massive stars, and to provide constraints on corresponding evolutionary models and aspects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.08146v2-abstract-full').style.display = 'none'; document.getElementById('1708.08146v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">22 pages, 16 figures, 6 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 615, A4 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.06744">arXiv:1702.06744</a> <span> [<a href="https://arxiv.org/pdf/1702.06744">pdf</a>, <a href="https://arxiv.org/format/1702.06744">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1017/S1743921317002411">10.1017/S1743921317002411 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stellar Winds in Massive X-ray Binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-N%C3%BA%C3%B1ez%2C+S">Silvia Mart铆nez-N煤帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Bozzo%2C+E">Enrico Bozzo</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L+M">Lidia M. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Sidoli%2C+L">Lara Sidoli</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon Olof Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Blay%2C+P">Pere Blay</a>, <a href="/search/astro-ph?searchtype=author&query=Falanga%2C+M">Maurizio Falanga</a>, <a href="/search/astro-ph?searchtype=author&query=F%C3%BCrst%2C+F">Felix F眉rst</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%ADmenez-Garc%C3%ADa%2C+A">Angel G铆menez-Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Kreykenbohm%2C+I">Ingo Kreykenbohm</a>, <a href="/search/astro-ph?searchtype=author&query=K%C3%BChnel%2C+M">Matthias K眉hnel</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A">Andreas Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Torrej%C3%B3n%2C+J+M">Jos茅 Miguel Torrej贸n</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">J枚rn Wilms</a>, <a href="/search/astro-ph?searchtype=author&query=Podsiadlowski%2C+P">Philipp Podsiadlowski</a>, <a href="/search/astro-ph?searchtype=author&query=Manousakis%2C+A">Antonios Manousakis</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="1702.06744v1-abstract-short" style="display: inline;"> Strong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor's gravity and ionizing radiation can strongly influence the wind flow. Based on a coll… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06744v1-abstract-full').style.display = 'inline'; document.getElementById('1702.06744v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.06744v1-abstract-full" style="display: none;"> Strong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor's gravity and ionizing radiation can strongly influence the wind flow. Based on a collaborative effort of astronomers both from the stellar wind and the X-ray community, this presentation attempts to review our current state of knowledge and indicate avenues for future progress. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.06744v1-abstract-full').style.display = 'none'; document.getElementById('1702.06744v1-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">4 pages, 1 figure, to be published in the Proceedings of the IAU Symposium No. 329 "The lives and death-throes of massive stars"</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.04773">arXiv:1702.04773</a> <span> [<a href="https://arxiv.org/pdf/1702.04773">pdf</a>, <a href="https://arxiv.org/ps/1702.04773">ps</a>, <a href="https://arxiv.org/format/1702.04773">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/10.1051/0004-6361/201629210">10.1051/0004-6361/201629210 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Tarantula Survey XXVI: Properties of the O-dwarf population in 30 Doradus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sab%C3%ADn-Sanjuli%C3%A1n%2C+C">C. Sab铆n-Sanjuli谩n</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=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</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=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Garcia%2C+M">M. Garcia</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Brott%2C+I">I. Brott</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=de+Koter%2C+A">A. de Koter</a>, <a href="/search/astro-ph?searchtype=author&query=de+Mink%2C+S+E">S. E. de Mink</a>, <a href="/search/astro-ph?searchtype=author&query=Gr%C3%A4fener%2C+G">G. Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Grin%2C+N+J">N. J. Grin</a>, <a href="/search/astro-ph?searchtype=author&query=Holgado%2C+G">G. Holgado</a>, <a href="/search/astro-ph?searchtype=author&query=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Ram%C3%ADrez-Agudelo%2C+O+H">O. H. Ram铆rez-Agudelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</a>, <a href="/search/astro-ph?searchtype=author&query=Taylor%2C+W+D">W. D. Taylor</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</a>, <a href="/search/astro-ph?searchtype=author&query=Walborn%2C+N+R">N. R. Walborn</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1702.04773v1-abstract-short" style="display: inline;"> The VLT-FLAMES Tarantula Survey has observed hundreds of O-type stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). We study the properties of 105 apparently single O-type dwarfs. To determine stellar and wind parameters, we used the IACOB-GBAT package, an automatic procedure based on a large grid of atmospheric models calculated with the FASTWIND code. In addition to classical tec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04773v1-abstract-full').style.display = 'inline'; document.getElementById('1702.04773v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.04773v1-abstract-full" style="display: none;"> The VLT-FLAMES Tarantula Survey has observed hundreds of O-type stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). We study the properties of 105 apparently single O-type dwarfs. To determine stellar and wind parameters, we used the IACOB-GBAT package, an automatic procedure based on a large grid of atmospheric models calculated with the FASTWIND code. In addition to classical techniques, we applied the Bayesian BONNSAI tool to estimate evolutionary masses. We provide a new calibration of effective temperature vs. spectral type for O-type dwarfs in the LMC, based on our homogeneous analysis of the largest sample of such objects to date and including all spectral subtypes. Good agreement with previous results is found, although the sampling at the earliest subtypes could be improved. Rotation rates and helium abundances are studied in an evolutionary context. We find that most of the rapid rotators (vsini higher than 300 km/s ) in our sample have masses below 25 MSun and intermediate rotation-corrected gravities (log gc between 3.9 and 4.1). Such rapid rotators are scarce at higher gravities (i.e. younger ages) and absent at lower gravities (larger ages). This is not expected from theoretical evolutionary models, and does not appear to be due to a selection bias in our sample. We compare the estimated evolutionary and spectroscopic masses, finding a trend that the former is higher for masses below 20 MSun. This can be explained as a consequence of limiting our sample to the O-type stars, and we see no compelling evidence for a systematic mass discrepancy. For most of the stars in the sample we were unable to estimate the wind-strength parameter (hence mass-loss rates) reliably, particularly for objects with luminosity lower than logL/LSun about 5.1. Ultraviolet spectroscopy is needed to undertake a detailed investigation of the wind properties of these dwarfs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04773v1-abstract-full').style.display = 'none'; document.getElementById('1702.04773v1-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 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">23 pages, 16 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 601, 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/1701.08618">arXiv:1701.08618</a> <span> [<a href="https://arxiv.org/pdf/1701.08618">pdf</a>, <a href="https://arxiv.org/ps/1701.08618">ps</a>, <a href="https://arxiv.org/format/1701.08618">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1007/s11214-017-0340-1">10.1007/s11214-017-0340-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Towards a unified view of inhomogeneous stellar winds in isolated supergiant stars and supergiant high mass X-ray binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mart%C3%ADnez-N%C3%BA%C3%B1ez%2C+S">Silvia Mart铆nez-N煤帽ez</a>, <a href="/search/astro-ph?searchtype=author&query=Kretschmar%2C+P">Peter Kretschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Bozzo%2C+E">Enrico Bozzo</a>, <a href="/search/astro-ph?searchtype=author&query=Oskinova%2C+L+M">Lidia M. Oskinova</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Sidoli%2C+L">Lara Sidoli</a>, <a href="/search/astro-ph?searchtype=author&query=Sundqvist%2C+J+O">Jon Olof Sundqvist</a>, <a href="/search/astro-ph?searchtype=author&query=Blay%2C+P">Pere Blay</a>, <a href="/search/astro-ph?searchtype=author&query=Falanga%2C+M">Maurizio Falanga</a>, <a href="/search/astro-ph?searchtype=author&query=F%C3%BCrst%2C+F">Felix F眉rst</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%ADmenez-Garc%C3%ADa%2C+%C3%81">脕ngel G铆menez-Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Kreykenbohm%2C+I">Ingo Kreykenbohm</a>, <a href="/search/astro-ph?searchtype=author&query=K%C3%BChnel%2C+M">Matthias K眉hnel</a>, <a href="/search/astro-ph?searchtype=author&query=Sander%2C+A">Andreas Sander</a>, <a href="/search/astro-ph?searchtype=author&query=Torrej%C3%B3n%2C+J+M">Jos茅 Miguel Torrej贸n</a>, <a href="/search/astro-ph?searchtype=author&query=Wilms%2C+J">J枚rn Wilms</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="1701.08618v2-abstract-short" style="display: inline;"> Massive stars, at least $\sim$ 10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive stars helped to re-ionize the Universe after… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.08618v2-abstract-full').style.display = 'inline'; document.getElementById('1701.08618v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1701.08618v2-abstract-full" style="display: none;"> Massive stars, at least $\sim$ 10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive stars helped to re-ionize the Universe after its Dark Ages. Another important property of massive stars are the strong stellar winds and outflows they produce. This mass loss, and finally the explosion of a massive star as a supernova or a gamma-ray burst, provide a significant input of mechanical and radiative energy into the interstellar space. These two properties together make massive stars one of the most important cosmic engines: they trigger the star formation and enrich the interstellar medium with heavy elements, that ultimately leads to formation of Earth-like rocky planets and the development of complex life. The study of massive star winds is thus a truly multidisciplinary field and has a wide impact on different areas of astronomy. [...] This detailed review summarises the current knowledge on the theory and observations of winds from massive stars, as well as on observations and accretion processes in wind-fed high mass X-ray binaries. The aim is to combine in the near future all available theoretical diagnostics and observational measurements to achieve a unified picture of massive star winds in isolated objects and in binary systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.08618v2-abstract-full').style.display = 'none'; document.getElementById('1701.08618v2-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 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 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">Published at Journal of Space Science Reviews, Springer</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1701.04758">arXiv:1701.04758</a> <span> [<a href="https://arxiv.org/pdf/1701.04758">pdf</a>, <a href="https://arxiv.org/format/1701.04758">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/10.1051/0004-6361/201628914">10.1051/0004-6361/201628914 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The VLT-FLAMES Tarantula Survey XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ram%C3%ADrez-Agudelo%2C+O+H">O. H. Ram铆rez-Agudelo</a>, <a href="/search/astro-ph?searchtype=author&query=Sana%2C+H">H. Sana</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=Tramper%2C+F">F. Tramper</a>, <a href="/search/astro-ph?searchtype=author&query=Grin%2C+N+J">N. J. Grin</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=Langer%2C+N">N. Langer</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Markova%2C+N">N. Markova</a>, <a href="/search/astro-ph?searchtype=author&query=Bestenlehner%2C+J+M">J. M. Bestenlehner</a>, <a href="/search/astro-ph?searchtype=author&query=Castro%2C+N">N. Castro</a>, <a href="/search/astro-ph?searchtype=author&query=Crowther%2C+P+A">P. A. Crowther</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+C+J">C. J. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Garc%C3%ADa%2C+M">M. Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Gr%C3%A4fener%2C+G">G. Gr盲fener</a>, <a href="/search/astro-ph?searchtype=author&query=Herrero%2C+A">A. Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=van+Kempen%2C+B">B. van Kempen</a>, <a href="/search/astro-ph?searchtype=author&query=Lennon%2C+D+J">D. J. Lennon</a>, <a href="/search/astro-ph?searchtype=author&query=Apell%C3%A1niz%2C+J+M">J. Ma铆z Apell谩niz</a>, <a href="/search/astro-ph?searchtype=author&query=Najarro%2C+F">F. Najarro</a>, <a href="/search/astro-ph?searchtype=author&query=Sab%C3%ADn-Sanjuli%C3%A1n%2C+C">C. Sab铆n-Sanjuli谩n</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=Taylor%2C+W+D">W. D. Taylor</a>, <a href="/search/astro-ph?searchtype=author&query=Vink%2C+J+S">J. S. Vink</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="1701.04758v3-abstract-short" style="display: inline;"> The Tarantula region in the Large Magellanic Cloud contains the richest population of spatially resolved massive O-type stars known so far. This unmatched sample offers an opportunity to test models describing their main-sequence evolution and mass-loss properties. Using ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stell… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.04758v3-abstract-full').style.display = 'inline'; document.getElementById('1701.04758v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1701.04758v3-abstract-full" style="display: none;"> The Tarantula region in the Large Magellanic Cloud contains the richest population of spatially resolved massive O-type stars known so far. This unmatched sample offers an opportunity to test models describing their main-sequence evolution and mass-loss properties. Using ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stellar, photospheric and wind properties of 72 presumably single O-type giants, bright giants and supergiants and to confront them with predictions of stellar evolution and of line-driven mass-loss theories. We apply an automated method for quantitative spectroscopic analysis of O stars combining the non-LTE stellar atmosphere model {\sc fastwind} with the genetic fitting algorithm {\sc pikaia} to determine the following stellar properties: effective temperature, surface gravity, mass-loss rate, helium abundance, and projected rotational velocity. We present empirical effective temperature versus spectral subtype calibrations at LMC-metallicity for giants and supergiants. In the spectroscopic and classical Hertzsprung-Russell diagrams, our sample O stars are found to occupy the region predicted to be the core hydrogen-burning phase by Brott et al. (2011) and K枚hler et al. (2015). Except for five stars, the helium abundance of our sample stars is in agreement with the initial LMC composition. The aforementioned five stars present moderate projected rotational velocities (i.e., $v_{\mathrm{e}}\,\sin\,i\,<\,200\,\mathrm{km\,s^{-1}}$) and hence do not agree with current predictions of rotational mixing in main-sequence stars. Adopting theoretical results for the wind velocity law, we find modified wind momenta for LMC stars that are $\sim$0.3 dex higher than earlier results. [Due to the limitation of characters, the abstract appearing here is slightly shorter than that in the PDF file.] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1701.04758v3-abstract-full').style.display = 'none'; document.getElementById('1701.04758v3-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 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 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">39 pages, 12 figures in the main text, 12 figures in the appendix. Accepted for publication in A&A. Tables C1-C5 will be available at the CDS. Appendix E has been truncated due to size limitations, the full version will be available on 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 600, A81 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.08964">arXiv:1611.08964</a> <span> [<a href="https://arxiv.org/pdf/1611.08964">pdf</a>, <a href="https://arxiv.org/format/1611.08964">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/stw3126">10.1093/mnras/stw3126 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic massive stars as progenitors of "heavy" stellar-mass black holes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Petit%2C+V">V. Petit</a>, <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Z. Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=MacInnis%2C+R">R. MacInnis</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+D+H">D. H. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Townsend%2C+R+H+D">R. H. D. Townsend</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G+A">G. A. Wade</a>, <a href="/search/astro-ph?searchtype=author&query=Thomas%2C+S+L">S. L. Thomas</a>, <a href="/search/astro-ph?searchtype=author&query=Owocki%2C+S+P">S. P. Owocki</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">J. Puls</a>, <a href="/search/astro-ph?searchtype=author&query=ud-Doula%2C+J+A">J. A. ud-Doula</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.08964v1-abstract-short" style="display: inline;"> The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of "heavy" stellar-mass BHs with masses >25 Msun. Initial modelling of the system by Abbott et al. (2016a) supposes that the formation of black holes with such large masses from the evolution of single massive stars is only feasible if the w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.08964v1-abstract-full').style.display = 'inline'; document.getElementById('1611.08964v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.08964v1-abstract-full" style="display: none;"> The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of "heavy" stellar-mass BHs with masses >25 Msun. Initial modelling of the system by Abbott et al. (2016a) supposes that the formation of black holes with such large masses from the evolution of single massive stars is only feasible if the wind mass-loss rates of the progenitors were greatly reduced relative to the mass-loss rates of massive stars in the Galaxy, concluding that heavy BHs must form in low-metallicity (Z < 0.25-0.5 Zsun) environments. However, strong surface magnetic fields also provide a powerful mechanism for modifying mass loss and rotation of massive stars, independent of environmental metallicity (ud-Doula & Owocki 2002; ud-Doula et al. 2008). In this paper we explore the hypothesis that some heavy BHs, with masses >25 Msun such as those inferred to compose GW150914, could be the natural end-point of evolution of magnetic massive stars in a solar-metallicity environment. Using the MESA code, we developed a new grid of single, non-rotating, solar metallicity evolutionary models for initial ZAMS masses from 40-80 Msun that include, for the first time, the quenching of the mass loss due to a realistic dipolar surface magnetic field. The new models predict TAMS masses that are significantly greater than those from equivalent non-magnetic models, reducing the total mass lost by a strongly magnetized 80 Msun star during its main sequence evolution by 20 Msun. This corresponds approximately to the mass loss reduction expected from an environment with metallicity Z = 1/30 Zsun. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.08964v1-abstract-full').style.display = 'none'; document.getElementById('1611.08964v1-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 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">10 pages, 7 figures, 1 table. 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/1610.04812">arXiv:1610.04812</a> <span> [<a href="https://arxiv.org/pdf/1610.04812">pdf</a>, <a href="https://arxiv.org/ps/1610.04812">ps</a>, <a href="https://arxiv.org/format/1610.04812">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/10.1051/0004-6361/201629468">10.1051/0004-6361/201629468 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modeling the early evolution of massive OB stars with an experimental wind routine </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Keszthelyi%2C+Z">Zsolt Keszthelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Puls%2C+J">Joachim Puls</a>, <a href="/search/astro-ph?searchtype=author&query=Wade%2C+G">Gregg Wade</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.04812v2-abstract-short" style="display: inline;"> Stellar evolution models of massive stars are very sensitive to the adopted mass-loss scheme. The magnitude and evolution of mass-loss rates significantly affect the main sequence evolution, and the properties of post-main sequence objects, including their rotational velocities. Driven by potential discrepancies between theoretically predicted and observationally derived mass-loss rates in the OB… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.04812v2-abstract-full').style.display = 'inline'; document.getElementById('1610.04812v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.04812v2-abstract-full" style="display: none;"> Stellar evolution models of massive stars are very sensitive to the adopted mass-loss scheme. The magnitude and evolution of mass-loss rates significantly affect the main sequence evolution, and the properties of post-main sequence objects, including their rotational velocities. Driven by potential discrepancies between theoretically predicted and observationally derived mass-loss rates in the OB star range, we particularly aim to investigate the response to mass-loss rates that are lower than currently adopted, in parallel with the mass-loss behavior at the "first" bi-stability jump. We perform 1D hydrodynamical model calculations of single $20 - 60 \, M_{\odot}$ Galactic ($Z = 0.014$) stars where the effects of stellar winds are already significant during the main sequence phase. We develop an experimental wind routine to examine the behavior and response of the models under the influence of different mass-loss rates. This observationally guided, simple and flexible wind routine is not a new mass-loss description but a useful tool based on the Wind-momentum Luminosity Relation and other scaling relations, and provides a meaningful base for various tests and comparisons. The main result of this study indicates a dichotomy when accounting for currently debated problems regarding mass-loss rates of hot massive stars. In a fully diffusive approach, and for commonly adopted initial rotational velocities, lower mass-loss rates than theoretically predicted require to invoke an additional source of angular momentum loss (either due to bi-stability braking, or yet unidentified) to brake down surface rotational velocities. [...] <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.04812v2-abstract-full').style.display = 'none'; document.getElementById('1610.04812v2-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">v1</span> submitted 15 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted by Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 598, A4 (2017) </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" 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