The Influence of the Decay of OB Associations on the Evolution of Dwarf Galaxies

Abstract

It is commonly believed that most of the stars born in associations decaying with characteristic velocities of stars ~10 km/s. For dwarf galaxies the decay can lead to ejection of stars from the galaxy. The effect is studied for spheroidal and disk dwarf galaxies, and is shown to have substantional observational consequences for disk galaxies with escape velocities up to 20 km/s, or dynamical masses up to 10^8 M_sol. The ejection of stars can (i) reduce the abundances of the products of Type Ia supernovae and, to a lesser degree, Type II supernovae, in disk stars, (ii) chemically enrich the galactic halo and intergalactic medium, (iii) lead to the loss of 50% of the stellar mass in galaxies with masses ~10^7 M_sol and the loss of all stars in system with masses 10^5 M_sol, (iv) increase the mass-to-luminosity ratio of the galaxies.