SIMBAD references

2015A&A...580A..32M - Astronomy and Astrophysics, volume 580A, 32-32 (2015/8-1)

The first stars: a classification of CEMP-no stars.

MAEDER A. and MEYNET G.

Abstract (from CDS):

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 ≤-2.5. This classification is based on the changes in abundances for the elements and isotopes involved in the CNO, Ne-Na, and Mg-Al nuclear cycles. These abundances change very much owing to successive back and forth mixing motions between the He- and H-burning regions in massive stars (the ``source stars'' responsible for the chemical enrichment of the CEMP-no stars). The wide variety of the ratios [C/Fe], 12C/13C, [N/Fe], [O/Fe], [Na/Fe], [Mg/Fe], [Al/Fe], [Sr/Fe], and [Ba/Fe], which are the main characteristics making the CEMP-no and low-s stars so peculiar, is described well in terms of the proposed nucleosynthetic classification. We note that the [(C+N+O)/Fe] ratios significantly increase for lower values of [Fe/H]. The classification of CEMP-no stars and the behavior of [(C+N+O)/Fe] support the presence, in the first stellar generations of the Galaxy, of fast-rotating massive stars experiencing strong mixing and mass loss (spinstars). This result has an impact on the early chemical and spectral evolution of the Galaxy.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: Population III - stars: massive - stars: low-mass - stars: evolution - Galaxy: evolution

CDS comments: Segue 1-7 is SDSS J100814.44+160501.1 in SIMBAD. 53327-2044-515 is SDSS J014036.22+234458.1 in SIMBAD.

Simbad objects: 48

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2020.09.21-08:00:25

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