Carbon abundance in beta Persei and lambda Tauri.

Abstract

A carbon abundance analysis of two Algol-type stars is performed using IUE archival data released for general use. The primaries of Beta Per and Lambda Tau show carbon abundances equal to log N(C/H) = -3.87 + or - 0.20 and 3.88 + or - 0.20, respectively. The results should be compared with the cosmic value of -3.48 given by Allen (1973). A C-deficiency favors the generally accepted evolutionary status of Algol-type stars. The conversion of C to N by the CNO cycle is expected in stellar interiors and products of this nucleosynthesis may be exposed now in the atmospheres of stars, due to a large-scale transfer of mass between the components. However, the observed carbon abundances in Beta Per and Lambda Tau are markedly larger than those expected. A suggestion is made that a large-scale mixing of matter occurs in these stars.