相关论文: Clues about the first stars from CEMP-no stars

The CEMP-no stars are long-lived small mass stars presenting a very low iron content and overabundances of carbon with no sign or only very weak signs for the presence of s- or r-elements. Although the origin of that abundance pattern is…

Context. CEMP-no stars are long-lived low-mass stars with a very low iron content, overabundances of carbon and no or minor signs for the presence of s- or r-elements. Although their origin is still a matter of debate, they are often…

(Abridged) The CEMP--no stars are "carbon-enhanced-metal-poor" stars that in principle show no evidence of s-- and r--elements from neutron captures. We try to understand the origin and nucleosynthetic site of their peculiar CNO, Ne--Na,…

We show that the peculiar surface abundance patterns of Carbon Enhanced Metal Poor (CEMP) stars has been inherited from material having been processed by H- and He-burning phases in a previous generation of stars (hereafter called the…

We propose and apply a new classification for the CEMP-no stars, which are "carbon-enhanced metal-poor" stars with no overabundance of s-elements and with [Fe/H] generally inferior or equal to -2.5. This classification is based on the…

An increasing fraction of carbon-enhanced metal-poor (CEMP) stars is found as their iron abundance, [Fe/H], decreases below [Fe/H] = -2.0. The CEMP-s stars have the highest absolute carbon abundances, [C/H], and are thought to owe their…

Metal-poor stars provide the fossil record of Galactic chemical evolution and the nucleosynthesis processes that took place at the earliest times in the history of our Galaxy. From detailed abundance studies of low mass, extremely…

We present a novel scenario for the formation of carbon-enhanced metal-poor (CEMP) stars. Carbon enhancement at low stellar metallicities is usually considered a consequence of faint or other exotic supernovae. An analytical estimate of…

We investigate anew the distribution of absolute carbon abundance, $A$(C) $= \log\,\epsilon $(C), for carbon-enhanced metal-poor (CEMP) stars in the halo of the Milky Way, based on high-resolution spectroscopic data for a total sample of…

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…

The first stars were likely more massive than those forming today and thus rapidly evolved, exploding as supernovae and enriching the surrounding gas with their chemical products. In the Local Group, the chemical signature of the first…

Carbon enhanced metal poor (CEMP) stars with low abundances of neutron capture elements (CEMP-no stars) are ubiquitous among metal poor stars in the Milky Way. Recent observations have uncovered their two subgroups that differ in the carbon…

The study of the long-dead early generations of massive stars is crucial in order to obtain a complete picture of the chemical evolution of the Universe, hence the origin of the elements. The nature of these stars can be inferred indirectly…

The elemental-abundance signatures of the very first stars are imprinted on the atmospheres of CEMP-no stars, as various evidence suggests they are bona-fide second-generation stars. It has recently been recognized that the CEMP-no stars…

The origin of carbon-enhanced metal-poor (CEMP) stars and their possible connections with the chemical elements produced by the first stellar generations is still highly debated. We briefly review observations of CEMP stars in different…

We use detailed nucleosynthesis calculations and a realistic prescription for the environment of the first stars to explore the first episodes of chemical enrichment that occurred during the dark ages. Based on these calculations, we…

The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely…

Carbon-enhanced metal-poor (CEMP) stars are the living fossils holding records of chemical enrichment from early generations of stars. In this work, we perform a set of numerical simulations of the enrichment from a supernova (SN) of a…

The origin of Carbon Enhanced Metal-Poor (CEMP-no) stars with low abundances of neutron-capture elements is still unclear. These stars are ubiquitous, found primarily in the Milky Way halo and ultra-faint dwarf galaxies (UFDs). To make a…

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…