Related papers: Pulsations as a mass-loss trigger in evolved hot s…
Massive stars can develop into tepid supergiants at several stages of their post main-sequence evolution, prior to core He-burning, on a blue loop, or close to the final supernova explosion. We discuss observational constraints on models of…
Some massive stars experience episodic and intense mass loss phases with fluctuations in the luminosity. Ejected material forms circumstellar matter around the star, and the subsequent core collapse results in a Type IIn supernova that is…
Eclipsing systems are essential objects for understanding the properties of stars and stellar systems. Eclipsing systems with pulsating components are furthermore advantageous because they provide accurate constraints on the component…
It is shown for the first time that the stripped helium stars with masses 2 to 7 solar mass which are formed in close binary systems in the so-called case B of mass-exchange and retained low-mass hydrogen-helium envelopes, experience…
First, we review the main physical effects to be considered in the building of evolutionary models of rotating stars on the Upper Main-Sequence (MS). The internal rotation law evolves as a result of contraction and expansion, meridional…
Discoveries of exoplanets orbiting evolved stars motivate critical examinations of the dynamics of $N$-body systems with mass loss. Multi-planet evolved systems are particularly complex because of the mutual interactions between the…
We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover…
The post main-sequence evolution of massive stars is very sensitive to many parameters of the stellar models. Key parameters are the mixing processes, the metallicity, the mass-loss rate and the effect of a close companion. We study how the…
Massive stars briefly pass through the yellow supergiant (YSG) phase as they evolve redward across the HR diagram and expand into red supergiants (RSGs). Higher-mass stars pass through the YSG phase again as they evolve blueward after…
Massive stars play a major role not only in stellar evolution but also galactic evolution theory. This is because of their dynamical interaction with binary companions, and because their strong winds and explosive deaths as supernovae…
The evolution of star clusters is determined by several internal and external processes. Here we focus on two dominant internal effects, namely energy exchange between stars through close encounters (two-body relaxation) and mass-loss of…
Massive stars and their supernovae are prominent sources of radioactive isotopes, the observations of which thus can help to improve our astrophysical models of those. Our understanding of stellar evolution and the final explosive endpoints…
Those massive stars that, during their deaths, give rise to gamma-ray bursts (GRBs) must be endowed with an unusually large amount of angular momentum in their inner regions, one to two orders of magnitude greater than the ones that make…
Winds from massive stars (> 8 solar masses) result in the formation of wind-blown "bubbles" around these stars. In this paper we study, via two-dimensional numerical hydrodynamic simulations, the onset and growth of turbulence during the…
Massive stars having a CO core of $\sim$40-60 M$_\odot$ experience pulsational pair-instability (PPI) after carbon-burning. This instability induces strong pulsations of the whole star and a part of outer envelope is ejected. We investigate…
We assume that the strong convection during core helium flash of low mass red giant branch (RBG) stars excite waves that propagate to the envelope, and find that the energy that these waves deposit in the envelope causes envelope expansion…
Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain,…
I discuss the role played by short-duration eruptive mass loss in the evolution of very massive stars. Giant eruptions of Luminous Blue Variables (LBVs) like the 19th century event of eta Carinae can remove large quantities of mass almost…
Stellar evolution models of massive stars are very sensitive to the adopted mass-loss scheme. The magnitude and evolution of mass-loss rates significantly affect the main sequence evolution, and the properties of post-main sequence objects,…
In the earliest phases of their evolution, stars gain mass through the acquisition of matter from their birth clouds. The widely accepted classical concept of early stellar evolution neglects the details of this accretion phase and assumes…