## Northern Kentucky University

# Dynamics of Molecular Clouds

## Institution

Northern Kentucky University

## Faculty Advisor/ Mentor

Lisa Holden

## Abstract

Star formation is a complex process and constitutes one of the basic problems of astrophysics. Most stars in our galaxy form within large cloud-like structures of molecular gas. Through the fragmentation of these large clouds, dense cores of gas form that ultimately collapse into single stars. We concentrated on analyzing the gravitational collapse that occurs in molecular cloud cores just prior to star formation. It had been shown that the collapse of the core is characterized by the rate at which mass falls onto the central object which in turn related observationally to the total luminosity of the system. Previous studies had focused on calculating the mass infall rate for sphericallyshaped cores under a variety of conditions. Motivated by observations, we sought to extend this body of literature by considering the gravitational collapse of cylindricallyshaped cores. The gravitational collapse of the cores we considered is described by a set of partial differential equations for self-gravitating fluids. These equations allowed for a self-similar analysis, enabling us to reduce the system to a set of ordinary differential equations. Initial conditions were obtained through an asymptotic analysis of the system and the ordinary differential equations were then solved using standard numerical techniques. We present the results of our analysis and compare our results to those obtained previously for spherically-shaped cores.

Dynamics of Molecular Clouds

Star formation is a complex process and constitutes one of the basic problems of astrophysics. Most stars in our galaxy form within large cloud-like structures of molecular gas. Through the fragmentation of these large clouds, dense cores of gas form that ultimately collapse into single stars. We concentrated on analyzing the gravitational collapse that occurs in molecular cloud cores just prior to star formation. It had been shown that the collapse of the core is characterized by the rate at which mass falls onto the central object which in turn related observationally to the total luminosity of the system. Previous studies had focused on calculating the mass infall rate for sphericallyshaped cores under a variety of conditions. Motivated by observations, we sought to extend this body of literature by considering the gravitational collapse of cylindricallyshaped cores. The gravitational collapse of the cores we considered is described by a set of partial differential equations for self-gravitating fluids. These equations allowed for a self-similar analysis, enabling us to reduce the system to a set of ordinary differential equations. Initial conditions were obtained through an asymptotic analysis of the system and the ordinary differential equations were then solved using standard numerical techniques. We present the results of our analysis and compare our results to those obtained previously for spherically-shaped cores.