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The VLT-FLAMES survey of massive stars : rotation and nitrogen enrichment as the key to understanding massive star evolution
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hunter, I. P. Brott, I. Lennon, David J. Langer, Norbert Dufton, Philip L. Trundle, Carrie Smartt, S. J. Koter, Alex De Evans, Christopher J. Ryans, Robert S. I. |
| Abstract | Rotation has become an important element in evolutionary models of massive stars, specifically via the prediction of rotational mixing. Here, we study a sample of stars, including rapid rotators, to constrain such models and use nitrogen enrichments as a probe of the mixing process. Chemical compositions (C, N, O, Mg and Si) have been estimated for 135 early B-type stars in the Large Magellanic Cloud with projected rotational velocities up to ∼300 km s −1 using a non-LTE tlusty model atmosphere grid. Evolutionary models, including rota-tional mixing, have been generated attempting to reproduce these observations by adjusting the overshooting and rotational mixing parameters and produce reasonable agreement with 60% of our core hydrogen burning sample. We find (excluding known binaries) a significant population of highly nitrogen enriched intrinsic slow rotators (v sin i 50 km s −1) incompatible with our models (∼20% of the sample). Furthermore, while we find fast rotators with enrichments in agreement with the models, the observation of evolved (log g < 3.7dex) fast ro-tators that are relatively unenriched (a further ∼20% of the sample) challenges the concept of rotational mixing. We also find that 70% of our blue supergiant sample cannot have evolved directly from the hydrogen burning main-sequence. We are left with a picture where invoking binarity and perhaps fossil magnetic fields are required to understand the surface properties of a population of massive main sequence stars. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0711.2267v2.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Compaq LTE Composition FOSSIL Field electron emission GUCY2C protein, human Gene Ontology Term Enrichment Hydrogen Iron Magellanic Catalogue of Stars Projections and Predictions Silicon Stars, Celestial Virtual Link Trunking |
| Content Type | Text |
| Resource Type | Article |
