Spectroscopic study of CEMP-(s & r/s) stars
نویسندگان
چکیده
منابع مشابه
Spectroscopic orbits and variations of RS Oph
Aims. The aims of our study are to improve the orbital elements of the giant, and to derive the spectroscopic orbit for the white dwarf companion. Spectral variations related to the 2006 outburst are also studied. Methods. We performed an analysis of about seventy optical and near infrared spectra of RS Oph that were acquired between 1998 and June 2008. The spectroscopic orbits have been obtain...
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Context. Carbon-Enhanced Metal-Poor (CEMP) stars are known to be the direct witnesses of the nucleosynthesis of the first lowand intermediate-mass stars, because most have been polluted by a now-extinct AGB star. Aims. By considering the various CEMP subclasses separately, we try to derive, from the specific signatures imprinted on the abundances, parameters (such as metallicity, mass, temperat...
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Time-resolved spectra in the 410 700 nm range have been obtained to investigate 10 stars which are classified as suspected chemically peculiar stars in The General Catalogue of Ap and Am stars by Renson et al. (1991) or in the latest literature. Among the studied stars, HD20629 presents metal abundances which are significantly different from main sequence star values and it should be classified...
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We examine the metallicity distribution function (MDF) and fraction of carbon-enhanced metal-poor (CEMP) stars in a sample that includes 86 stars with [Fe/H] ≤ −3.0, based on high-resolution, high-S/N spectroscopy, of which some 32 objects lie below [Fe/H] = −3.5. After accounting for the completeness function, the “corrected” MDF does not exhibit the sudden drop at [Fe/H] = −3.6 that was found...
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Observations of five D-type symbiotics are presented: three oxygen Mira (He2-38, H2-38 and H1-36) and two carbon Mira symbiotics (AS 210 and SS 38). The observations in the spectral range between 3200Å and 7400Å show the presence of several emission lines in various states of excitation. A line list is provided with their suggested identifications. Several parameters were derived for each objec...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2021
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/202038258