New Estimates of the Solar-Neighborhood Massive-Stars Birthrate and the Galactic Supernova Rate

Abstract

The birthrate of stars of masses > 10 solar masses is estimated from a sample of just over 400 O3-B2 dwarfs within 1.5 kpc of the Sun and the result extrapolated to estimate the galactic supernova rate contributed by such stars. The solar-neighborhood galactic-plane massive star birthrate is estimated at 176 stars per cubic kpc per million years. Based on a model where the galactic stellar density distribution comprises a disk plus central hole like that of the dust infrared emission (Drimmel & Spergel 2001 ApJ 556, 181) the galactic supernova rate is estimated as probably not less than 1 nor more than 2 per century and the number of O3-B2 dwarfs within the solar circle as ~ 200,000.