The VLT-FLAMES Survey of Massive Stars: Observations centered on the Magellanic Cloud clusters NGC 330, NGC 346, NGC 2004, and the N11 region
TLDR
In this article, the Fibre Large Array Multi-element Spectrograph (FLAMES) was used to detect 470 stars in the Small Magellanic Cloud (SMC), NGC 2004 and the N11 region in the Large Magellan Cloud (LMC).Abstract:
We present new observations of 470 stars using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument in fields centered on the clusters NGC 330 and NGC 346 in the Small Magellanic Cloud (SMC), and NGC 2004 and the N11 region in the Large Magellanic Cloud (LMC). A further 14 stars were observed in the N11 and NGC 330 fields using the Ultraviolet and Visual Echelle Spectrograph (UVES) for a separate programme. Spectral classifications and stellar radial velocities are given for each target, with careful attention to checks for binarity. In particular we have investigated previously unexplored regions around the central LH9/LH10 complex of N11, finding ~25 new O-type stars from our spectroscopy. We have observed a relatively large number of Be-type stars that display permitted Fe II emission lines. These are primarily not in the cluster cores and appear to be associated with classical Be-type stars, rather than pre main-sequence objects. The presence of the Fe II emission, as compared to the equivalent width of H$\alpha$, is not obviously dependent on metallicity. We have also explored the relative fraction of Be- to normal B-type stars in the field-regions near to NGC 330 and NGC 2004, finding no strong evidence of a trend with metallicity when compared to Galactic results. A consequence of service observations is that we have reasonable time-sampling in three of our FLAMES fields. We find lower limits to the binary fraction of O- and early B-type stars of 23 to 36%. One of our targets (NGC346-013) is especially interesting with a massive, apparently hotter, less luminous secondary component.read more
Citations
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Rotating massive main-sequence stars - I. Grids of evolutionary models and isochrones
Ines Brott,Ines Brott,S. E. de Mink,S. E. de Mink,Matteo Cantiello,Norbert Langer,Norbert Langer,A. de Koter,A. de Koter,Chris Evans,Ian Hunter,Carrie Trundle,Jorick S. Vink +12 more
TL;DR: In this paper, a dense grid of evolutionary tracks and isochrones of rotating massive main-sequence stars is presented to compare with early OB stars in the Small and Large Magellanic Clouds and in the Galaxy.
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Mass loss from hot massive stars
TL;DR: In this paper, the authors discuss various aspects of radiation-driven mass loss, both from the theoretical and the observational side, focusing on the winds from OB-stars, and discuss the problems of measuring mass loss rates from weak winds and the potential of the NIR Br α -line as a tool to enable a more precise quantification, and comment on physical explanations for mass-loss rates that are much lower than predicted by the standard model.
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The empirical metallicity dependence of the mass-loss rate of O- and early B-type stars
M. R. Mokiem,A. de Koter,Jorick S. Vink,Joachim Puls,Chris Evans,Stephen J. Smartt,Paul A. Crowther,Artemio Herrero,Artemio Herrero,Norbert Langer,D. J. Lennon,Francisco Najarro,M. R. Villamariz +12 more
TL;DR: In this paper, a comprehensive study of the observational dependence of the mass-loss rate in stationary stellar winds of hot massive stars on the metal content of their atmospheres is presented, and critical assessment is given of state-of-the-art mass loss determinations of OB stars in these two satellite systems and the Milky-Way.
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The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
Ian Hunter,Ines Brott,Norbert Langer,D. J. Lennon,Philip Dufton,Ian D. Howarth,Robert Ryans,Carrie Trundle,Chris Evans,A. de Koter,A. de Koter,Stephen Smartt +11 more
TL;DR: In this article, the spectral properties of early B-type stars in the Large Magellanic Cloud (LMC) were analyzed and compared to the spectra of the Small Magellan Cloud (SMC) metallicities.
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Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
TL;DR: For example, the authors showed that mass loss rates for standard metallicity-dependent winds of hot stars are lower by a factor of 2-3 compared with rates adopted in modern stellar evolution codes, due to the influence of clumping on observed diagnostics.
Journal ArticleDOI
Mass loss from hot massive stars
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