ASTRONOMY & ASTROPHYSICS JUNE I 1999, PAGE 351 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 137, 351–362 (1999) Understanding A-type supergiants I. Ultraviolet and visible spectral atlas? of A-type supergiants,?? E. Verdugo1,A.Talavera2,andA.I.G´omez de Castro3 1 ISO Data Centre, P.O. Box 50727, E-28080-Madrid, Spain e-mail:
[email protected] 2 LAEFF/INTA, P.O. Box 50727, E-28080-Madrid, Spain e-mail: ati@laeff.esa.es 3 Instituto de Astronom´ıa y Geodesia (CSIC-UCM), Fac. cc. Matem´aticas, Universidad Complutense, Av. Complutense s/n, E-28040-Madrid, Spain e-mail:
[email protected] Received October 14, 1997; accepted April 12, 1999 Abstract. This paper is the first of a series whose aim is number and the quality of the observational studies of stel- to perform a systematic study of A-type supergiant atmo- lar winds. At the same time the theory of stellar winds has spheres and winds. Here we present a spectral atlas of 41 been improved dramatically. However most of this work A-supergiants observed by us in high and medium reso- has been limited to O and B stars. To date, very few stud- lution in the visible and ultraviolet. The atlas consists of ies have been devoted to A-type supergiants. These stars profiles of the Hα,Hβ,Hγ,Hδ,H,CaII (H and K), Na I occupy a region of the HR diagram where evolution is (D1 and D2), Mg II4481,MgII [uv1] and Fe II [uv1, uv2, rapid and therefore they are few in number.