C II abundances in early-type stars: solution to a notorious non-LTE problem

Abstract

We address a long-standing discrepancy between non-LTE analyses of the prominent C II 4267 and 6578/82 A multiplets in early-type stars. A comprehensive non-LTE model atom of C II is constructed based on critically selected atomic data. This model atom is used for an abundance study of six apparently slow-rotating main-sequence and giant early B-type stars. High-resolution and high-S/N spectra allow us to derive highly consistent abundances not only from the classical features but also from up to 18 further C II lines in the visual - including two so far unreported emission features equally well reproduced in non-LTE. These results require the stellar atmospheric parameters to be determined with care. A homogeneous (slightly) sub-solar present-day carbon abundance from young stars in the solar vicinity (in associations and in the field) of log C/H +12= 8.29+/-0.03 is indicated.

8 pages, 5 figures

Cited by in corpus (18)

• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• A cosmic abundance standard: chemical homogeneity of the solar neighbourhood and the ISM dust-phase composition
• The VLT-FLAMES survey of massive stars: Evolution of surface N abundances and effective temperature scales in the Galaxy and Magellanic Clouds
• Carbon Deficiency in Externally-Polluted White Dwarfs: Evidence for Accretion of Asteroids
• Quantitative studies of the optical and UV spectra of Galactic early B supergiants I. Fundamental parameters
• Abundance analysis of prime B-type targets for asteroseismology I. Nitrogen excess in slowly-rotating beta Cephei stars
• Hydrogen and helium line formation in OB dwarfs and giants. A hybrid non-LTE approach
• Neon Abundances in B-Stars of the Orion Association: Solving the Solar Model Problem?
• Runaway and hypervelocity stars in the Galactic halo: Binary rejuvenation and triple disruption
• Planetary nebulae abundances and stellar evolution
• Carbon abundances of early B-type stars in the solar vicinity. Non-LTE line-formation for C II/III/IV and self-consistent atmospheric parameters
• LMC origin of the hyper-velocity star HE 0437-5439. Beyond the supermassive black hole paradigm
• The Nature of the Hyper-Runaway Candidate HIP 60350
• Quantitative spectroscopy of Deneb
• HVS7: a chemically peculiar hyper-velocity star
• Low Metallicity Indicates that the Hypervelocity Star HE 0437-5439 was Ejected from the LMC
• Iron abundances of B-type post-Asymptotic Giant Branch stars in globular clusters: Barnard 29 in M 13 and ROA 5701 in omega Cen
• Mixing of CNO-cycled matter in massive stars