Combining observational techniques to constrain convection in evolved massive star models

C. Georgy, H. Saio, G. Meynet

Research output: Contribution to journalArticle

Abstract

Recent stellar evolution computations indicate that massive stars in the range ~ 20-30 M are located in the blue supergiant (BSG) region of the Hertzsprung-Russell diagram at two different stages of their life: immediately after the main sequence (MS, group 1) and during a blueward evolution after the red supergiant phase (group 2). From the observation of the pulsationnal properties of a subgroup of variable BSGs (α Cyg variables), one can deduce that these stars belongs to group 2. It is however difficult to simultaneously fit the observed surface abundances and gravity for these stars, and this allows to constrain the physical processes of chemical species transport in massive stars. We will show here that the surface abundances are extremely sensitive to the physics of convection, particularly the location of the intermediate convective shell that appears at the ignition of the hydrogen shell burning after the MS. Our results show that the use of the Ledoux criterion to determine the convective regions in the stellar models leads to a better fit of the surface abundances for α Cyg variables than the Schwarzschild one.

Original languageEnglish
Pages (from-to)47-51
Number of pages5
JournalProceedings of the International Astronomical Union
Volume9
DOIs
Publication statusPublished - 2014 Jan 1

Keywords

  • abundances-stars: early-type-stars: evolution-stars: mass loss-stars: oscillations

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science

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