W. J. Maciel -
Abstract #114
A SURVEY OF EARLY-TYPE STARS BASED ON THE 2MASS DATABASE
R. Ortiz, M. Malacarne, R. Wilhelm, R. D. D. Costa, S. Rossi, W. J. Maciel, A. F. M. Costa
Astron. J. 134, 1183-1194 (2007) We report results of a spectroscopic survey of blue stars near the south galactic pole, selected according to their colour indices in the 2MASS database. The main scope of this work is to determine the nature of the objects that comprise the sample. Some characteristics of the Hbeta, Halpha and Hdelta lines which are sensitive to temperature and gravity have been measured and were eventually compared with a grid of model atmospheres to obtain Teff and log(g). In some cases the data allowed a unique, reliable classification of the star. Among the 44 stars studied, 5 objects are reliably classified as subdwarfs, 12 as A-type stars, and 3 as field horizontal-branch (FHB) stars. The remaining objects are either A or FHB stars, but additional observations are necessary to distinguish between these two types. Neither degenerate nor low-gravity stars (post-AGB) have been identified in the sample.
