Accretion centers induced in a molecular cloud core after a penetrating collision

Abstract

The aim of this paper is to present a set of numerical simulations of a penetrating collision, in which a small gas core (the bullet) penetrates a larger gas core (the target). In the target core, the gravitational collapse is supposed to be ongoing before the collision. Each colliding core has a uniform density profile and rigid body rotation; besides the mass and size of the target core have been chosen to represent the observed molecular cloud core L1544. We modified the Lagrangian code Gagdet2 to identify when a gas particle can become an accretion center, and to inherit the mass and momentum of all the very close neighboring particles. Three collision models are here considered for pre-collision velocities v/c0= 2.5, 5.0, and 10 Mach. The outcome of these collision models are presented only for two different values of the bullet’s radius, that is for R0/ 4, and R0/2 where R0 is the radius of the target core. Such collision models reveal how accretion centers are formed, with a spatial distribution that strongly depends on the pre-collision velocity. We thus show hereby that penetrating collisions may have a major and favorable influence in the star formation process.