相关论文: Pre-supernova mixing in CEMP-no source stars

During galaxy-galaxy interactions, massive gas clouds can be injected into the intergalactic medium which in turn become gravitationally bound, collapse and form stars, star clusters or even dwarf galaxies. The objects resulting from this…

We calculate nucleosynthesis in Population (Pop) III supernovae (SNe) and compare the yields with various abundance patterns of extremely metal-poor (EMP) stars. We assume that the observed EMP stars are the second generation stars, which…

Most of relatively warm, unevolved metal-poor stars ($T_{\rm eff}\gtrsim 5800\,\mathrm{K}$ and $[{\rm Fe/H}]\lesssim -1.5$) exhibit almost constant lithium abundances, irrespective of metallicity or effective temperature, and thus form the…

We present a comprehensive multi-wavelength study of 5 poststarburst galaxies with $M_\ast > 10^{11} M_\odot$ at $z\sim 0.7$, examining their stars, gas, and current and past star-formation activities. Using optical images from the Subaru…

Mixing processes such as convection, overshooting and rotational mixing have long been known to affect the evolutionary properties of low-mass stars. While modeling a 1.2 Msun star, we encountered a semiconvective region outside the fully…

Evolved low-mass stars of a wide range of metallicity bear signatures of a non-standard mixing event in their surface abundances of Li, C, and N, and in their 12C/13C ratio. A Na overabundance has also been reported in some giants of open…

The fraction of binary systems in various stellar populations of the Galaxy and the distribution of their orbital parameters are important but not well-determined factors in studies of star formation, stellar evolution, and Galactic…

We present a detailed abundance analysis of 23 elements for a newly discovered carbon-enhanced metal-poor (CEMP) star, HE 0414-0343, from the Chemical Abundances of Stars in the Halo (CASH) Project. Its spectroscopic stellar parameters are…

(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…

(Abridged) Aims. To investigate the first stages of the process of high-mass star formation, we selected a sample of massive clumps previously observed with the SEST at 1.2 mm and with the ATNF ATCA at 1.3 cm. We want to characterize the…

We present models for the slow neutron-capture process (s process) in asymptotic giant branch (AGB) stars of metallicity [Fe/H]=-2.3 and masses 0.9 Msun to 6 Msun. We encountered different regimes of neutron-capture nucleosynthesis…

We review the main properties of solar metallicity massive stars in the range 11-120 Msun. The influence of the mass loss on the hydrostatic burning stages as well as the final explosion is discussed in some detail. We find that the minimum…

We investigate the evolution of the surface properties of models for rotating massive stars, i.e., their luminosities, effective temperatures, surface rotational velocities, and surface abundances of all isotopes, from the zero age main…

We present preliminary results of stellar structure and nucleosynthesis calculations for some early stars. The study (still in progress) seeks to explore the expected chemical signatures of second generation low- and intermediate-mass stars…

The observed abundance diversities among the CEMP stars can shed light on the formation and evolution of elements in the early Galaxy. In this work, we present results obtained from a detailed abundance analysis of a sample of seven…

We present late-time HST images of the site of supernova (SN) 2009ip taken almost 3 yr after its bright 2012 luminosity peak. SN 2009ip is now slightly fainter in broad filters than the progenitor candidate detected by HST in 1999. The…

Tentative evidence that the properties of evolved stars with planets may be different from what we know for MS hosts has been recently reported. We aim to test whether evolved stars with planets show any chemical peculiarity that could be…

Some useful developments in the model physics are briefly presented, followed by model results on chemical enrichments and WR stars. We discuss the expected rotation velocities of WR stars. We emphasize that the (C+O)/He ratio is a better…

We present a detailed study of the evolution of massive stars of masses 15, 20, 25 and 30 $\msun$ assuming solar-like initial chemical composition. The stellar sequences were evolved through the advanced burning phases up to the end of core…

Metal-poor stars are key for studying the formation and evolution of the Galaxy. Evidence of the early mergers that built up the Galaxy remains in the distributions of abundances, kinematics, and orbital parameters of its stars. Several…