Spectroscopic analysis of the suspected AM star 15 Vulpeculae.

Abstract

The suspected Am star 15 Vul is characterized using the ATLAS-6 model-atmosphere program of Kurucz (1979) and spectrograms (resolution 10 and 4 A/mm) obtained with the coudespectrograph of the 1.88-m reflector at Okayama Astrophysical Observatory during September and October 1981; comparison stars are 28 And and 9 Aur. The data and calculated abundances are presented in graphs and tables. The Am-like anomaly of 15 Vul is shown to be more like that of Delta Del than of a typical Ap or Am star, while its H-R-diagram location suggests it was once a main-sequence Ap star. It is proposed that an existing deep Am-like anomaly surfaced by convective mixing after surface convection had disrupted a surface Ap-like anomaly.