Understanding A-type supergiants - II. Atmospheric parameters and rotational velocities of galactic A-type supergiants

Abstract

We present the second paper of a series whose aim is to perform a global study of Galactic A-supergiants. Very little work has been carried out to determine the stellar parameters of these stars. This is illustrated with a brief review of some previous works. In this paper we analyze the determination of absolute magnitudes, spectral types and atmospheric parameters using the most recent Kurucz LTE blanketed model atmospheres and we discuss the applicability of the calibrations, such as the Schmidt-Kaler's (1982) calibration. Rotation is also an important parameter in A-supergiants but their rotational velocities are poorly known. We have calculated projected rotational velocities from the Fourier analysis of the observed Mg II (4481 Angstrom) line.