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

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 and ultraviolet. The atlas consists of profiles of the Hα , Hβ , Hγ , Hdelta , Hepsilon , 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. Figures 1-3 are only available in electronic form at the http://www.edpsciences.com} of A-type supergiants\fnmsep\thanks{Based on observations made with the INT and JKT telescopes operated on the island of La Palma by the RGO in the Spanish Observatorio del Roque de Los Muchachos of the Instituto de Astrofisica de Canarias, with the 2.2~m telescope at Calar Alto Observatory, Spain, with the Bernard Lyot 2~m telescope at Pic Du Midi Observatory, France and observations collected at the European Southern Observatory at La Silla, Chile.