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

摘要

This paper is the rst of a series whose aim is\udto perform a systematic study of A-type supergiant atmospheres\udand winds. Here we present a spectral atlas of 41\udA-supergiants observed by us in high and medium resolution\udin the visible and ultraviolet. The atlas consists of\udpro les of the H , H , H\ud, H , H , Ca II (H and K), Na I\ud(D1 and D2), Mg II4481, Mg II [uv1] and Fe II [uv1, uv2,\uduv3, uv62, uv63, uv161] lines for 41 stars with spectral\udtypes ranging from B9 to A9 and luminosity classes Ia,\udIab and Ib, and provides the basic data for a thoughtful\udstudy of these stars. The overall characteristics of the sample\udas well as the data reduction procedures are described.\udWe also present some examples of spectral variability.