PG 0009+036: a rapidly rotating normal B star in the galactic halo.

Abstract

We present the spectroscopic analysis of a rapidly rotating main sequence B star at high galactic latitude. From optical and ultraviolet spectra of PG 0009+036 we find for the atmospherical parameters T_eff_=14500K, logg=3.9, and a rotational velocity of vsini=320km/s. The effects of rotation on the fundamental parameters of the star are discussed and a mass of 4.8-5.8M_sun_ is derived. PG 0009+036 is located 5.0-5.4kpc below the galactic plane at a distance of 5.9-6.4kpc. The star is most likely born in the disk and afterwards ejected into the halo.