Threedimensional dynamics of protostellar evolution.
Abstract
A threedimensional finitedifference numerical technique is outlined for selfgravitating rotating gaseous systems. The full nonlinear timedependent equations describing a rotating selfgravitating fluid are solved in rotating cylindrical coordinates, and the timedependent adiabatic collapse of gravitationally bound rotating protostellar clouds is analyzed for specified uniform and nonuniform initial conditions. It is found that uniform clouds can form axisymmetric rotating toroidal configurations, that nonuniform clouds can collapse to axisymmetric ellipsoids if the thermal pressure is high, and that the collapsing cloud is unstable to perturbations for low thermal pressures. The ensuing fragmentation of unstable protostellar clouds is examined by studying the response of selfgravitating equilibrium toroids to nonaxisymmetric perturbations. The results show that the detailed evolution of a fragmenting toroid depends on a nondimensional function of the initial entropy, as well as the total mass in the toroid, the rotational angular velocity, and the number of perturbation wavelengths around the circumference of the toroid.
 Publication:

The Astrophysical Journal
 Pub Date:
 November 1978
 DOI:
 10.1086/156568
 Bibcode:
 1978ApJ...225.1005C
 Keywords:

 Finite Difference Theory;
 Protostars;
 Stellar Evolution;
 Stellar Models;
 Chandrasekhar Equation;
 Dynamic Models;
 Gravitational Collapse;
 Rotating Matter;
 Toroids;
 Astrophysics;
 Collapse:Protostellar Clouds;
 Hydrodynamics:Star Formation