相关论文: Stellar yields in CNO from rotating stellar models
High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy…
The effects of rotation on stellar evolution are particularly important at low metallicity, when mass loss by stellar winds diminishes and the surface enrichment due to rotational mixing becomes relatively more pronounced than at high…
Context. Rotation is known to affect the nucleosynthesis of light elements in massive stars, mainly by rotation-induced mixing. In particular, rotation boosts the primary nitrogen production. Models of rotating stars are able to reproduce…
The most massive stars provide an essential source of recycled material for young clusters and galaxies. While very massive stars (VMS, M>100M) are relatively rare compared to O stars, they lose disproportionately large amounts of mass…
Calculations that demonstrate the influence of three key nuclear reaction rates on the evolution of Asymptotic Giant Branch stars have been carried out. We study the case of a star with an initial mass of 2Msun and a metallicity of Z=0.01,…
High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy…
The main objective of the present work is to ckeck if the star formation efficiency plays a relevant role in the evolution of the relative abundance N/O. We analyze the evolution of the nitrogen-to-oxygen ratio as predicted by a set of…
Grids of models of massive stars ($M \ge$ 20 $M_\odot$) with rotation are computed for metallicities $Z$ ranging from that of the Small Magellanic Cloud (SMC) to that of the Galactic Centre. The hydrostatic effects of rotation, the…
Employing the the stellar evolution code (Modules for Experiments in Stellar Astrophysics), we calculate yields of heavy elements from massive stars via stellar wind and core-collapse supernovae (CCSN) ejecta to interstellar medium (ISM).…
We employ analytical and numerical chemical evolution models to study observed trends in abundance ratios involving carbon, nitrogen, and oxygen. Several sets of published stellar yields for both intermediate-mass and massive stars are…
The effects of rotation on low-metallicity stellar models are twofold: first, the models reach break-up during main sequence and may lose mass by mechanical process; second, strong internal mixing brings freshly synthesized elements towards…
Compression of the stellar winds from rapidly rotating hot stars is described by the wind compression model. However, it was also shown that rapid rotation leads to rotational distortion of the stellar surface, resulting in the appearance…
After summarizing the most important features of current stellar yields of CNO elements (including recent results concerning rotating and mass losing stars) I discuss how these yields may help to interpret relevant observations in the local…
We analyze the behavior of N/O and C/O abundance ratios as a function of metallicity as gauged by O/H in large, extant Galactic and extragalactic H II region abundance samples. Numerical chemical evolution models are computed using…
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 review some important observed properties of massive stars. Then we discuss how mass loss and rotation affect their evolution and help in giving better fits to observational constraints. Consequences for nucleosynthesis at different…
The Geneva evolutionary code has been modified to study the advanced stages (Ne, O, Si burnings) of rotating massive stars. Here we present the results of four 20 solar mass stars at solar metallicity with initial rotational velocities of…
Mass loss plays a dominant role in the evolution of massive stars at solar metallicity. After discussing different mass loss mechanisms and their metallicity dependence, we present the possibility of strong mass loss at very low…
The present paper discusses the main physical effects produced by stellar rotation on presupernovae, as well as observations which confirm these effects and their consequences for presupernova models. Rotation critically influences the mass…
After a review of the many effects of metallicity on the evolution of rotating and non-rotating stars, we discuss the consequences of a high metallicity on massive star populations and on stellar nucleosynthesis. The most striking effect of…