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Related papers: Caveats about measuring carbon abundances in stars…

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Context. Carbon, oxygen and nitrogen (CNO) are key elements in stellar formation and evolution, and their abundances should also have a significant impact on planetary formation and evolution. Aims. We present a detailed spectroscopic…

We present carbon and strontium abundances for 100 metal-poor stars measured from R$\sim $7000 spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory. Using spectral synthesis of the G-band region, we have…

Astrophysics · Physics 2009-11-13 David K. Lai , Jennifer A. Johnson , Michael Bolte , Sara Lucatello

[ABRIDGED]We study the carbon abundances with a twofold objective. On the one hand, we want to evaluate the behaviour of carbon in the context of Galactic chemical evolution. On the other hand, we focus on the possible dependence of carbon…

Solar and Stellar Astrophysics · Physics 2021-12-01 E. Delgado Mena , V. Adibekyan , N. C. Santos , M. Tsantaki , J. I. González Hernández , S. G. Sousa , S. Bertrán de Lis

We develop and test a method for the estimation of metallicities ([Fe/H]) and carbon abundance ratios ([C/Fe]) for carbon-enhanced metal-poor (CEMP) stars, based on application of artificial neural networks, regressions, and synthesis…

Among stars in Galactic globular clusters the carbon abundance tends to decrease with increasing luminosity on the upper red giant branch, particularly within the lowest metallicity clusters. While such a phenomena is not predicted by…

Solar and Stellar Astrophysics · Physics 2019-04-08 Jeffrey M. Gerber , Michael M. Briley , Graeme H. Smith

The X-shooter Spectral Library (XSL) is a large empirical stellar library used as a benchmark for the development of stellar population models. The inclusion of $\alpha$-elements abundances is crucial to disentangling the chemical evolution…

Astrophysics of Galaxies · Physics 2023-04-19 Pablo Santos-Peral , Patricia Sánchez-Blázquez , Alexandre Vazdekis , Pedro A. Palicio

Spectral indices are useful tools for quantifying the strengths of features in moderate-resolution spectra and relating them to intrinsic stellar parameters. This paper focuses on the 4300AA CH G-band, a classic example of a feature…

Astrophysics · Physics 2009-11-13 Sarah L. Martell , Graeme H. Smith , Michael M. Briley

We describe a method for the determination of stellar [C/Fe] abundance ratios using low-resolution (R = 2000) stellar spectra from the SDSS and SEGUE. By means of a star-by-star comparison with a set of SDSS/SEGUE spectra with available…

The correlation between host star iron abundance and the exoplanet occurrence rate is well-established and arrived at in several studies. Similar correlations may be present for the most abundant elements, such as carbon and oxygen, which…

Earth and Planetary Astrophysics · Physics 2022-10-13 Athira Unni , Mayank Narang , Thirupathi Sivarani , Manoj Puravankara , Ravinder K Banyal , Arun Surya , S. P. Rajaguru , C. Swastik

The determination of chemical abundances constitutes a fundamental requirement for obtaining a complete picture of a star. Particularly in massive stars, CNO abundances are of prime interest, due to the nuclear CNO-cycle and various mixing…

Solar and Stellar Astrophysics · Physics 2018-07-04 Luiz P. Carneiro , J. Puls , T. L. Hoffmann

We present a method to determine nitrogen abundance ratios with respect to iron ([N/Fe]) from molecular CN-band features observed in low-resolution ($R \sim$ 2000) stellar spectra obtained by the Sloan Digital Sky Survey (SDSS) and the…

Astrophysics of Galaxies · Physics 2022-05-25 Changmin Kim , Young Sun Lee , Timothy C. Beers , Thomas Masseron

A non-LTE analysis of C I lines at 1.068-1.069 micron was carried out for selected 46 halo/disk stars covering a wide metallicity range (-3.7 <[Fe/H]< +0.3), based on the spectral data collected with IRCS+AO188 of the Subaru Telescope, in…

Solar and Stellar Astrophysics · Physics 2015-06-15 Yoichi Takeda , Masahide Takada-Hidai

Precise determinations of the chemical composition in early B-type stars consitute fundamental observational constraints on stellar and galactochemical evolution. Carbon is one of the most abundant metals in the Universe but analyses in…

Astrophysics · Physics 2009-11-13 M. F. Nieva , N. Przybilla

Abundances of C, O, and Fe are determined for F and G main-sequence stars in the solar neighborhood in order to study trends and systematic differences in the C/Fe, O/Fe, and C/O ratios for stellar populations. Carbon abundances are…

Solar and Stellar Astrophysics · Physics 2014-09-05 P. E. Nissen , Y. Q. Chen , L. Carigi , W. J. Schuster , G. Zhao

Carbon and oxygen abundances in F and G main-sequence stars ranging in metallicity from [Fe/H] = -1.6 to +0.5 are determined from a non-LTE analysis of CI and OI atomic lines in high-resolution spectra. Both C and O are good tracers of…

Astrophysics of Galaxies · Physics 2015-06-16 Poul E. Nissen , William J. Schuster

Abundance analysis of carbon has been performed in a sample of 80 late F and early G type dwarf stars in the metallicity range -1.06 < [Fe/H] < 0.26 using the forbidden [C I] line at 8727 A. This line is presumably less sensitive to…

Astrophysics · Physics 2011-05-23 B. Gustafsson , T. Karlsson , E. Olsson , B. Edvardsson , N. Ryde

Photospheric C, N, and O abundances of 118 solar-analog stars were determined by applying the synthetic-fitting analysis to their spectra in the blue or near-UV region comprising lines of CH, NH, and OH molecules, with an aim of clarifying…

Solar and Stellar Astrophysics · Physics 2023-02-01 Yoichi Takeda

Stellar spectra derived from current multiple-object fiber-fed spectroscopic radial-velocity surveys, of the type feasible with, among other examples, AUTOFIB, 2dF, HYDRA, NESSIE, and the Sloan survey, differ significantly from those…

Astrophysics · Physics 2007-05-23 J. Bryn Jones , Rosemary F. G. Wyse , Gerard Gilmore

We present the results of an observational study of the efficiency of deep mixing in globular cluster red giants as a function of stellar metallicity. We determine [C/Fe] abundances based on low-resolution spectra taken with the Kast…

Astrophysics · Physics 2009-11-13 Sarah L. Martell , Graeme H. Smith , Michael M. Briley

The spectral lines of the CH molecule are a key carbon (C) abundance diagnostic in FGKM-type stars. These lines are detectable in metal-rich and, in contrast to atomic C lines, also in metal-poor late-type stars. However, only 3D LTE…

Solar and Stellar Astrophysics · Physics 2026-02-04 Richard Hoppe , Maria Bergemann , Philipp Eitner , Momo Ellwarth , Åke Nordlund , Jorrit Leenaarts , Bertrand Plez , Aldo Serenelli
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