相关论文: Very low metallicity massive star models: Pre-SN e…
We review general characteristics of massive stars, present the main observable constraints that stellar models should reproduce. We discuss the impact of massive star nucleosynthesis on the early phases of the chemical evolution of the…
(shortened) The first couple of stellar generations may have been massive, of order 100 Msun, and to have played a dominant role in galaxy formation and the chemical enrichment of the early Universe. Some fraction of these objects may have…
We present the first set of a new generation of models of massive stars of solar composition extending between 13 and 120 \msun, computed with and without the effects of rotation. We included two instabilities induced by rotation, namely…
We calculate new evolutionary models of rotating primordial very massive stars, with initial mass from $100\,M_{\odot}$ to $200\,M_{\odot}$, for two values of the initial metallicity ${Z=0}$ and ${Z=0.0002}$. For the first time in this mass…
At very low metallicity, the effects of differential rotation have a more important impact on the evolution of stars than at high metallicity. Rotational mixing leads to the production of great quantities of helium and of primary $^{14}$N…
Very massive stars (VMS) up to 200-300 $M_\odot$ have been found in the Local Universe. If they would lose little mass they produce intermediate-mass black holes or pair-instability supernovae (PISNe). Until now, VMS modellers have…
The first stars are assumed to be predominantly massive. Although, due to the low initial abundances of heavy elements the line-driven stellar winds are supposed to be inefficient in the first stars, these stars may loose a significant…
We examine the properties of Wolf--Rayet (WR) stars predicted by models of rotating stars taking account of the new mass loss rates for O--type stars and WR stars (Vink et al. \cite{Vink00}, \cite{Vink01}; Nugis & Lamers \cite{NuLa00}) and…
We present a dense model grid with tailored input chemical composition appropriate for the Large Magellanic Cloud. We use a one-dimensional hydrodynamic stellar evolution code, which accounts for rotation, transport of angular momentum by…
For $^{12}$C and $^{16}$O, rotating models predict in general enhanced yields. At high metallicity, the carbon and oxygen yields from the very high mass stars, which go through a WR phase, are little affected by rotation. For $^{14}$N,…
Stripped-envelope stars can be observed as Wolf-Rayet (WR) stars, or as less luminous hydrogen-poor stars with low mass loss rates and transparent winds. Both types are potential progenitors of Type I core-collapse supernovae (SNe). We use…
The nature of the first massive stars may be inferred by investigating the origin of the extremely metal-poor (EMP) stars, likely formed from the ejecta of one or a few previous massive stars. We investigate the rotational properties of…
Using the stellar evolution code---Modules for Experiments in Stellar Astrophysics (MESA), we investigate the evolution of massive stars with different rotational velocities and metallicities towards Wolf-Rayet stars. In our simulations,…
(abridged) Fast stellar rotation is currently the most promising mechanism for producing primary nitrogen in metal-poor massive stars. Chemical evolution models computed with the inclusion of the yields of fast rotating models at a…
Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this paper, we describe the strong…
We present extensive evolutionary models of stars with initial zero-metallicity, covering a large range of initial masses (i.e. 0.7 <= M <= 100 Msun). Calculations are carried out at constant mass, with updated input physics, and applying…
The chemical feedback from stellar winds in low metallicity (Z) environments is key for understanding the evolution of globular clusters and the early Universe. With disproportionate mass lost from the most massive stars (M > 100Msun), and…
Mass loss is a very important aspect of the life of massive stars. After briefly reviewing its importance, we discuss the impact of the recently proposed downward revision of mass loss rates due to clumping (difficulty to form Wolf-Rayet…
The Small Magellanic Cloud (SMC) hosts 12 known Wolf-Rayet (WR) stars, seven of which are apparently single. Their formation is a challenge for current stellar evolution models because line-driven winds are generally assumed to be quenched…
We study the spectroscopic appearance of very massive stars and their effect on the integrated light of starbursts at low metallicity (Z). We adopt two frameworks for the mass loss rates of VMS: in one case we assume no Z dependence, in the…