Detalles de publicación
PP 016003
OB stars at the lowest Local Group metallicity. GTC-OSIRIS observations of Sextans A
(1)Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain, (2)Departamento de Astrofísica, Universidad de la Laguna, Tenerife, Spain, (3)Centro de Astrobiología, CSIC/INTA, Madrid, Spain
Massive stars play an important role in the chemical and dynamical evolution of the Universe. The first metal-poor stars may have started the reionization of the Universe. To understand these early epochs it is necessary to know the behavior and the physical properties of massive stars in very metal-poor environments. We focus on the massive stellar content of the metal-poor irregular galaxy Sextans A. Our aim is to find and classify OB stars in Sextans A, to later determine accurate stellar parameters of these blue massive stars in this low metallicity region (Z∼0.1Z⊙).
Using UBV photometry, the reddening-free index Q and GALEX imaging, we built a list of blue massive star candidates in Sextans A. We obtained low resolution (R ∼ 1000) GTC-OSIRIS spectra for a fraction of them and carried out spectral classification. The observations were successful and have produced the first atlas of OB-type stars in Sextans. From the whole sample of 18 observed stars, 12 were classified as early OB-types, including 5 O-stars. Preliminary stellar parameters were derived for the O-type sub-sample.
Using UBV photometry, the reddening-free index Q and GALEX imaging, we built a list of blue massive star candidates in Sextans A. We obtained low resolution (R ∼ 1000) GTC-OSIRIS spectra for a fraction of them and carried out spectral classification. The observations were successful and have produced the first atlas of OB-type stars in Sextans. From the whole sample of 18 observed stars, 12 were classified as early OB-types, including 5 O-stars. Preliminary stellar parameters were derived for the O-type sub-sample.