A catalogue of galactic O stars and the ionization of the low density interstellar medium by runaway stars.
A catalogue of 664 galactic 0 stars is presented. For each object the following characteristics are presented: mv, B - V, spectral type, distance, radial velocity, radial component of the peculiar velocity, possible multiplicity of the object, whether the 0 star is inside or outside the faintest H II regions detectable on the Palomar Sky Survey prints and identification of the H II region where the star is projected. From this catalogue the luminosity function for 0 stars is computed. The hydrogen ionizing radiation from 0 stars not imbedded in H II regions is 1.3 x 10^-14 photons cm-3 s-1, and is very similar to that obtained by Torres-Peimbert, Lazcano-Araujo and Peimbert (1974) Out of 386 0 stars with known radial component of the peculiar velocities, Vnr, we have found 72 stars with |vnr| ≥ 30 km s-1; only 19 of them had been proposed previously as runaway candidates. On the other hand, 22 runaway candidates proposed by other authors have |vnr| < 30 km s-1 It is estimated that 20 to 30% of the total number of 0 stars are runaways. It is found that the mean distance to the galactic plane for 0 stars outside dense H II regions is 108 pc, for 0 stars inside H II regions, 54 pc, and for runaway candidates, 108 pc. The mean of the radial component of the peculiar velocities for stars inside dense H II regions is 14.6 km s-1, while for those outside it is 22.9 km s-1 It is found that while, for the whole sample, 53% of the stars are inside H II regions, of the runaway candidates only 33 % are inside. A brief discussion of the association between O stars and dense H II regions is given.
Revista Mexicana de Astronomia y Astrofisica
- Pub Date:
- November 1974