A<i>FUSE</i>SURVEY OF THE ROTATION RATES OF VERY MASSIVE STARS IN THE SMALL AND LARGE MAGELLANIC CLOUDS

Penny, Laura R.; Gies, Douglas R.

doi:10.1088/0004-637x/700/1/844

Cited by 70 publications

(72 citation statements)

References 54 publications

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“…Fast rotation has the effect of lengthening WR lifetimes, manifest predominantly in the eWNL phase, thus reducing NW C /NW N (Meynet & Maeder 2005). However, it is not expected that all massive stars are formed rotating as quickly (v rot i = 300 km s −1 ) as those generated in these models (Penny & Gies 2009). Figure 8 shows the number ratio of early to late WN stars in each Galactic metallicity zone, as well as in the LMC and SMC.…”

Section: Comparison To Evolutionary Predictionsmentioning

confidence: 99%

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Rosslowe

Crowther

2015

Monthly Notices of the Royal Astronomical Society

123

143

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We construct revised near-infrared absolute magnitude calibrations for 126 Galactic Wolf-Rayet (WR) stars at known distances, based in part upon recent large scale spectroscopic surveys. Application to 246 WR stars located in the field, permits us to map their Galactic distribution. As anticipated, WR stars generally lie in the thin disk (∼40 pc half width at half maximum) between Galactocentric radii 3.5-10 kpc, in accordance with other star formation tracers. We highlight 12 WR stars located at vertical distances of 300 pc from the midplane. Analysis of the radial variation in WR subtypes exposes a ubiquitously higher N W C /N W N ratio than predicted by stellar evolutionary models accounting for stellar rotation. Models for non-rotating stars or accounting for close binary evolution are more consistent with observations. We consolidate information acquired about the known WR content of the Milky Way to build a simple model of the complete population. We derive observable quantities over a range of wavelengths, allowing us to estimate a total number of 1200 +300 −100 Galactic WR stars, implying an average duration of ∼ 0.25 Myr for the WR phase at the current Milky Way star formation rate. Of relevance to future spectroscopic surveys, we use this model WR population to predict follow-up spectroscopy to K S ≃ 13 mag will be necessary to identify 95% of Galactic WR stars. We anticipate that ESA's Gaia mission will make few additional WR star discoveries via low-resolution spectroscopy, though will significantly refine existing distance determinations. Appendix A provides a complete inventory of 322 Galactic WR stars discovered since the VIIth catalogue (313 including Annex), including a revised nomenclature scheme.

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Section: Comparison To Evolutionary Predictionsmentioning

confidence: 99%

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Rosslowe

Crowther

2015

Monthly Notices of the Royal Astronomical Society

123

143

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“…As convincingly argued in Hirschi (2006), higher rotational velocities at lower metallicities are a consequence of angular momentum conservation, since less metallic stars are hotter and more compact than their higher metallicity counterparts. This theoretical argument seems to be supported by observations of rotating Be stars in the Magellanic Clouds and the Milky Way (Martayan et al 2007), although the observational situation is far from settled yet (see Penny & Gies 2009). …”

Section: Wind Composition Of Rotating Massive Starsmentioning

confidence: 83%

Production and evolution of Li, Be, and B isotopes in the Galaxy

Prantzos

2012

A&A

166

159

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Context. We reassess the problem of the production and evolution of the light elements Li, Be and B and of their isotopes in the Milky Way in the light of new observational and theoretical developments. Aims. The main novelty is the introduction of a new scheme for the origin of Galactic cosmic rays (GCR), which for the first time enables a self-consistent calculation of their composition during galactic evolution. Methods. The scheme accounts for key features of the present-day GCR source composition, it is based on the wind yields of the Geneva models of rotating, mass-losing stars and it is fully coupled to a detailed galactic chemical evolution code. Results. We find that the adopted GCR source composition accounts naturally for the observations of primary Be and helps understanding why Be follows Fe more closely than O. We find that GCR produce ∼70% of the solar 11 B/ 10 B isotopic ratio; the remaining 30% of 11 B presumably result from ν-nucleosynthesis in massive star explosions. We find that GCR and primordial nucleosynthesis can produce at most ∼30% of solar Li. At least half of the solar Li has to originate in low-mass stellar sources (red giants, asymptotic giant branch stars, or novae), but the required average yields of those sources are found to be much higher than obtained in current models of stellar nucleosynthesis. We also present radial profiles of LiBeB elemental and isotopic abundances in the Milky Way disc. We argue that the shape of those profiles -and the late evolution of LiBeB in general -reveals important features of the production of those light elements through primary and secondary processes.

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“…1,ab): υ sin i measurements in the Galaxy and in the Magellanic Clouds indicate that these are rapidly rotating stars, with a mean projected velocity of about 130 km.s −1 for B-type stars (Bragança et al 2012, Hunter et al 2008b, Mokiem et al 2006, Abt et al 2002, and about 110 km.s −1 for O-type stars (Penny 1996, Penny & Gies 2009). Some stars in the On subtype (with nitrogen enrichment) can reach projected velocities of about 420 km.s −1 (Walborn et al 2011) but the number of these very rapid rotators is actually limited.…”

Section: Measurements Of Stellar Rotationmentioning

confidence: 93%

Influence of Rotation on Stellar Evolution

Palacios

2013

EAS Publications Series

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Abstract. The Sun has been known to rotate for more than 4 centuries, and evidence is also available through direct measurements, that almost all stars rotate. In this lecture, I will propose a review of the different physical processes associated to rotation that are expected to impact the evolution of stars. I will describe in detail the way these physical processes are introduced in 1D stellar evolution codes and how their introduction in the modelling has impacted our understanding of the internal structure, nucleosynthesis and global evolution of stars.

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AFUSESURVEY OF THE ROTATION RATES OF VERY MASSIVE STARS IN THE SMALL AND LARGE MAGELLANIC CLOUDS

Cited by 70 publications

References 54 publications

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Production and evolution of Li, Be, and B isotopes in the Galaxy

Influence of Rotation on Stellar Evolution

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