Does Competitive Accretion Require a Cluster Environment?
Abstract
In the ``competitive accretion" picture, the high-mass end of the stellar initial mass function (IMF) results from continuing accretion onto the central star from a gas reservoir. Most simulations to date have been conducted assuming formation in a cluster gravitational potential. In this contribution we report a set of numerical simulations aimed at addressing the applicability of competitive accretion in an initially non-clustered environment. We conducted SPH simulations of gas accretion onto sink particles that are placed randomly in a flat geometry with a uniform surface density. We considered three test cases: one with initially equal mass sinks and uniform background density, another starting with equal mass sinks and nonuniform density, and the third starting with uniform density and varying clump masses. We studied the mass accretion history and the resulting mass distribution of the clumps. In all three cases, the IMF begins with or quickly develops a symmetric log normal distribution but later develops a power law that flattens and approaches the Salpeter slope. Higher mass sinks form preferentially in small compact groups of sinks. Our results suggest that competitive accretion could work well in a wider variety of circumstances than previously discussed.
- Publication:
-
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21541415H