Luminosity function of solar-neighborhood OB stars

The luminosity function of solar-neighborhood OB stars is derived from a sample of nearly 2600 such objects brighter than m(pg) = 10 via a method that makes use of varying completeness-to-distance estimates depending on the absolute magnitudes of the sample members and their (assumed) exponential density distribution perpendicular to the Galactic plane. The derived luminosity function is in good agreement with that published previously by Humphreys and McElroy over the range -7 < M-v < -4. The integrated Galactic plane density of OB stars within this range of absolute magnitudes is estimated at 9.1 x 10(-7) stars pc(-3), and the total number of OB stars within the solar circle is estimated at similar to 19,000. The predicted number of OB stars more massive than 20 solar masses within 2.5 kpc of the Sun, 636, is 50% greater than the value of 424 given earlier by Germany et al., indicating that their sample was not as complete as they had assumed.