Accretion Centers Induced in a Molecular Cloud Core After a Penetrating Collision - Selected Topics of Computational and Experimental Fluid Mechanics - page 478

Accretion Centers Induced in a Molecular
Cloud Core After a Penetrating Collision

G. Arreaga-García and J. Klapp

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 Gagdet 2 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 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 R 0 /

/ c 0 = 2 . 5, 5 .

2 where R 0 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.

4, and R 0 /

1 Introduction

Gas cloud collisions may play an important role in the star formation process by
altering the physical processes in the involved clouds, including their gravitational