An Etymological Dictionary of Astronomy and Astrophysics

A scenario for → massive star formation whereby developing → protostars in their natal → molecular clouds compete with each other to gather mass. The protostars → accrete mass with a rate which depends on their location within the protocluster. They use the same reservoir of gas to grow. Therefore those protostars nearest the center, where the potential well is deep, and gas densities are higher, have the highest → accretion rates. The competitive accretion model explains the observational fact that the most massive stars are generally found in cluster cores. It accounts also for the distribution of stellar masses. In this model the accretion process depends on the content of the cluster. In clusters where gas dominates the potential (e.g. at initial stages of cluster formation),
the accretion process is better modeled by using the → tidal radius as the accretion radius. In contrast, when the stars dominate the cluster potential and are virialized, the accretion is better modeled by → Bondi-Hoyle accretion (Bonnell et al. 1997, MNRAS 285, 201; 2001, MNRAS 323, 785).

See also: → competitive; → accretion; → model.