Understanding A-type supergiants - I. Ultraviolet and visible spectral atlas of A-type supergiants

Abstract

This paper is the first of a series whose aim is to perform a systematic study of A-type supergiant atmospheres and winds. Here we present a spectral atlas of 41 A-supergiants observed by us in high and medium resolution in the visible asd ultraviolet. The atlas consists of profiles of the H alpha, H beta, H gamma, H delta, H epsilon, Ca II (H and K), Na I (D1 and D2), Mg II4481, Mg II [uv1] and Fe II [uv1, uv2; uv3, uv62, uv63, uv161] lines for 41 stars with spectral types ranging from B9 to A9 and luminosity classes Ia, Iab and Ib, and provides the basic data for a thoughtful study of these stars. The overall characteristics of the sample as well as the data reduction procedures are described. We also present some examples of spectral variability.