An Etymological Dictionary of Astronomy and Astrophysics

The → accretion of mass by a star (assumed as point particle) moving at a steady speed through an infinite, uniform gas cloud.
It is directly proportional to the star mass (M) and the medium density (ρ) and inversely proportional to the relative star/gas velocity (v). In its classical expression:
4πρ(G M)² / v³, where G is the → gravitational constant. See Bondi & Hoyle (1944, MNRAS 104, 273) and Bondi (1952, MNRAS 112, 195). For a recent treatment of accretion in a turbulent medium see Krumholtz et al. 2006 (ApJ 638, 369).

See also: Named after Hermann Bondi (1919-2005), an Anglo-Austrian mathematician and cosmologist and Fred Hoyle (1915-2001), British mathematician and astronomer best known as the foremost proponent and defender of the steady-state theory of the universe; → accretion.