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Astron. Astrophys. 346, 819-830 (1999)

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Understanding A-type supergiants

II. Atmospheric parameters and rotational velocities of Galactic A-type supergiants *

E. Verdugo 1, A. Talavera 2 and A.I. Gómez de Castro 3

1 ISO Data Centre, P.O. Box 50727, E-28080 Madrid, Spain (everdugo@iso.vilspa.esa.es)
2 LAEFF/INTA, P.O. Box 50727, E-28080 Madrid, Spain (ati@laeff.esa.es)
3 Instituto de Astronomía y Geodesia (CSIC-UCM), Fac. cc. Matemáticas, Universidad Complutense, Av. Complutense s/n, E-28040 Madrid, Spain (aig@orion.mat.ucm.es)

Received 14 October 1997 / Accepted 12 April 1999


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 Å) line.

Key words: stars: atmospheres – stars: fundamental parameters – stars: mass-loss – stars: supergiants

* 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 2.2m telescope at Calar Alto Observatory, Spain, with the Bernard Lyot 2m telescope at Pic Du Midi Observatory, France and observations collected at the European Southern Observatory at La Silla, Chile

Send offprint requests to: E. Verdugo

© European Southern Observatory (ESO) 1999

Online publication: June 17, 1999