相关论文: Chemical Evolution of CNO abundances

A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus…

The detailed composition of most metal-poor halo stars has been found to be very uniform. However, a fraction of 20-70% (increasing with decreasing metallicity) exhibit dramatic enhancements in their abundances of carbon - the so-called…

Context. Carbon, nitrogen, and oxygen are the most abundant elements throughout the universe, after hydrogen and helium. Studying these elements in low-metallicity stars can provide crucial information on the chemical composition in the…

In this paper we emphasize the close connection between the chemical and spectrophotometric evolution of stellar systems: Chemical yields from stars correspond to a precise fraction of their emitted light. We translate this concept…

Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant…

The high metallicity of the intra-cluster medium (ICM) is generally interpreted on the base of the galactic wind scenario for elliptical galaxies. In this framework, we develop a toy-model to follow the chemical evolution of the ICM,…

We present new sets of chemical yields from low- and intermediate-mass stars with 0.8 Msun <= M <= Mup ~ 5 Msun, and three choices of the metallicity, Z=0.02, Z=0.008, and Z=0.004 (Marigo 2000, in preparation). These are then compared with…

In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models…

Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g. stellar radiation, winds or explosions, or by their environment. While the metallicity depletion…

Intermediate mass stars occupy the mass range between 0.8-8 solar masses. In this review, evolutionary models of these stars from numerous sources are compared in terms of their input physics and predicted yields. In particular, the results…

We have developed a grid of chemical evolution models applied to dwarf isolated galaxies, using \cite{gav05} yields. The input data enclose different star formation efficiencies, galaxy mass and collapse time values. The result is a wide…

Abundance patterns of the elements C, N, and O are sensitive probes of stellar nucleosynthesis processes and, in addition, O abundances are an important input for stellar age determinations. Understanding the nature of the observed…

The studies focused on the Thermally-Pulsing Asymptotic Giant Branch phase experienced by low- and intermediate-mass stars are extremely important in many astrophysical contexts. In particular, a detailed computation of their chemical…

The supernovae SN II & Ib/c make major stellar nucleosynthetic contributions to the inventories of the stable nuclides during the chemical evolution of the galaxy. A case study is performed here with the help of recently developed numerical…

We present a comprehensive study of the evolution of the abundances of intermediate mass elements, from C to Zn, in the Milky Way halo and in the local disk. We use a consistent model to describe the evolution of those two galactic…

Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun's composition, that of stars in the solar neighbourhood, and of the estimated "pristine" compositions for stellar systems. The…

We present a dual-infall galactic chemical evolution model which uses a new set of stellar yields calculated by Limongi et al (2001) to constrain the amount of iron-peak elements ejected by massive stars. The age-metallicity relation,…

Rotating massive stars at $Z=10^{-8}$ and $10^{-5}$ lose a great part of their initial mass through stellar winds. The chemical composition of the rotationally enhanced winds of very low $Z$ stars is very peculiar. The winds show large CNO…

Chemical abundances provide important clues to the evolution of galaxies. Ionized nebulae are one of the main sources of chemical abundance measurements, especially in external galaxies. Studies of H II regions have shown that the overall…

We use state-of-the-art chemical models to track the cosmic evolution of the CNO isotopes in the interstellar medium (ISM) of galaxies, yielding powerful constraints on their stellar initial mass function (IMF). We re-assess the relative…