Analysis of C II resonance lines in some main sequence early-type stars.

Abstract

An analysis of C II resonance lines at 1335 Å in eight main-sequence stars of spectral types A0 to B3 is performed using IUE archival data released for general use. In order to interpret the observed spectra, both LTE and non-LTE line profiles were computed. In stars with low rotational velocities (Vega, π Cet, τ Her and ι Her) the authors obtained logarithmic carbon abundances log N(C/H) = -3.55 to -3.45 in non-LTE case. LTE analysis indicates lower carbon abundances by about 0.1 dex. Substantial differences are found among the fast rotating stars. In 28 Vul the authors obtain log N(C/H) = -3.52±0.20, whereas ψ²Aqr, α Leo and 7 Cep have log N(C/H) = -4.90±0.20, -4,32±0.20 and -4.02±0.20, respectively.