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| Paper: |
Stellar Evolution in the Upper HR Diagram |
| Volume: |
425, Hot and Cool: Bridging Gaps in Massive Star Evolution |
| Page: |
13 |
| Authors: |
Hirschi, R.; Meynet, G.; Maeder, A.; Ekström, S.; Georgy, C. |
| Abstract: |
Massive stars evolve through many different stages (O-type, blue, yellow and red supergiant, luminous blue variable and Wolf-Rayet stars) during their lifetime and produce various types of supernovae (type II, Ib, Ic, IIn, gamma-ray bursts). The goal of this paper is to review the evolution of massive stars in the Hertzsprung-Russell (HR) diagram from a theoretical point of view in order to explain the link between the different stages (O-type to Wolf-Rayet stars) in which massive stars are observed. After recalling the general picture of the evolution of massive stars in the HR diagram, we describe how physical ingredients (mass loss, rotation, magnetic fields) affect the evolution of stars in the HR diagram. We then compare models to observations, in particular ratios of stars in different stages (red to blue supergiants, Wolf-Rayet to O-type stars, type II to type Ib,c supernova). Taking into account the metallicity dependence of mass-loss rates in all stages as well as including the effects of rotation significantly improves the reproduction of observations by models. We also discuss the evolution of GRB progenitors and the possibility of stars dying in the LBV stage and producing SNIIn, which has recently been suggested by observations. |
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