Carbon abundance and the N/C ratio in atmospheres of A-, F- and G-type supergiants and bright giants

@article{Lyubimkov2015CarbonAA,
  title={Carbon abundance and the N/C ratio in atmospheres of A-, F- and G-type supergiants and bright giants},
  author={L S Lyubimkov and David L. Lambert and Sergey A. Korotin and Tamara M. Rachkovskaya and Dmitry B. Poklad},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2015},
  volume={446},
  pages={3447-3460}
}
Based on our prior accurate determination of fundamental parameters for 36 Galactic A-, F- and G-type supergiants and bright giants (luminosity classes I and II), we undertook a non-LTE analysis of the carbon abundance in their atmospheres. It is shown that the non-LTE corrections to the C abundances derived from C I lines are negative and increase with the effective temperature Teff; the corrections are especially significant for the infrared C I lines with wavelengths 9060-9660 \AA. The… 
Analysis of the Non-LTE Lithium Abundance for a Large Sample of F-, G-, and K-Giants and Supergiants
A five-dimensional interpolation method and corresponding computer program are developed for using published calculations to determine the non-LTE correction ∆NLTE to the lithium abundance logε(Li)
The N/O Ratio in Early B-Type Main Sequence Stars as an Indicator of Their Evolution
It is shown that, in the case of early B-type main-sequence stars, of the three ratios N/C, C/O, and N/O which are regarded as indicators of stellar evolution, the ratio N/O is more reliable since it
Chemical diversity among A–B stars with low rotational velocities: non-LTE abundance analysis
We present accurate element abundance patterns based on the non-local thermodynamic equilibrium (non-LTE, NLTE) line formation for 14 chemical elements from He to Nd for a sample of nine A9 to B3
Three Nearby K-Giants with Planets: Accurate Determination of Basic Parameters, Including an Analysis of Metallicity Based on Fe I Lines
Fundamental parameters are determined for three bright, nearby K-giants, {\beta} Gem (K0 III), {\mu} Leo (K2 III), and {\alpha} Tau (K5 III). It is notable that around all three stars the giant
Atmospheric parameters and nitrogen abundances to investigate the role of binarity and the width of the main sequence
Context. Model atmosphere analyses have been previously undertaken for both Galactic and extragalactic B-type supergiants. By contrast, little attention has been given to a comparison of the
The Red Giants EK Eri and OU And as Probable Descendents of Ap-stars: A Search for Abundance Anomalies
The red giants EK Eri and OU And, with magnetic fields B max =99 and 41 G, respectively, which presumably are descendents of magnetic Ap-stars, are studied. Their fundamental parameters are found and
The CEMP star SDSS J0222–0313: the first evidence of proton ingestion in very low-metallicity AGB stars?
Context. Carbon-enhanced metal-poor (CEMP) stars are common objects in the metal-poor regime. The lower the metallicity we look at, the larger the fraction of CEMP stars with respect to metal-poor
High-resolution abundance analysis of HD 140283
HD 140283 is a reference subgiant that is metal poor and confirmed to be a very old star. The abundances of this type of old star can constrain the nature and nucleosynthesis processes that occurred
Lithium in Stellar Atmospheres: Observations and Theory
Of all the light elements, lithium is the most sensitive indicator of stellar evolution. This review discusses current data on the abundance of lithium in the atmospheres of A-, F-, G-, and K-stars
Light Chemical Elements in Stars: Mysteries and Unsolved Problems
The first eight elements of the periodic table are discussed: H, He, Li, Be, B, C, N, and O. They are referred to as key elements, given their important role in stellar evolution. It is noteworthy
...
...

References

SHOWING 1-10 OF 37 REFERENCES
Nitrogen enrichment in atmospheres of A- and F-type supergiants
Using new accurate fundamental parameters of 30 Galactic A and F supergiants, namely their effective temperatures T eff and surface gravities log g, we implemented a non-LTE analysis of the nitrogen
Carbon, nitrogen and oxygen abundances in atmospheres of the 5–11 M⊙ B-type main-sequence stars
Fundamental parameters and the carbon, nitrogen and oxygen abundances are determined for 22 B-type stars with distances up to 600 pc and slow rotation (vsini up to 66 km/s). The stars are selected
Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood
The following parameters are determined for 63 Galactic supergiants in the solar neighbourhood: effective temperature T eff ; surface gravity log g; iron abundance log ∈(Fe); microturbulent parameter
Lithium abundance in atmospheres of F- and G-type supergiants and bright giants
Lithium in the atmosphere of a F or G supergiant reflects the initial Li abundance and the internal history of the star. During evolution of a star from the main sequence (MS) to the supergiant
PARAMETERS AND ABUNDANCES IN LUMINOUS STARS
Parameters and abundances for 451 stars of spectral types F, G, and K of luminosity classes I and II have been derived. Absolute magnitudes and E(B – V) have been derived for the warmer stars in
Photospheric CNO Abundances of Solar-Type Stars
We determined the C, N, and O abundances of 160 nearby F, G, and K dwarfs and subgiants by using spectra obtained with the HIDES spectrograph at Okayama Astrophysical Observatory, with the purposes
Possible Overionization of C II, N II, and O II Ions in the Atmospheres of Early B- and Late O-Type Stars
The reliability of C, N, and O abundances determined from lines of C II, N II, and O II in the main-sequence (MS) early B- and late O-type stars is examined. This analysis is based on a fact of
Kinetic equilibrium of iron in the atmospheres of cool stars - III. The ionization equilibrium of selected reference stars
Non-LTE line formation calculations of Fei are performed for a small number of reference stars to investigate and quantify the eciency of neutral hydrogen collisions. Using the atomic model that was
Magellanic Clouds elemental abundances from F supergiants: Revisited results for the Large Magellanic Cloud
With an improved method of the LTE abundance analysis for most elements (Kovtyukh & Andrievsky 1999), the abundances have been re-investigated in nine F supergiants of the Large Magellanic Cloud. The
The non-LTE line formation of neutral carbon in late-type stars
Aims. We investigate the non-Local Thermodynamic Equilibrium (non-LTE) line formation of neutral carbon in late-type stars in order to remove some of the potential systematic errors in stellar
...
...