Stars

Astronomy

Accretion (finance)

Astrophysics

Hydrostatic equilibrium

Star formation

Protostar

Gravitational collapse

Physics

The Astrophysical Journal

We carry out radiation hydrodynamic calculations to study physical processes in the formation of a 1 M☉ protostar. Following our previous work, calculations pursue the whole evolution from the beginning of the first collapse to the end of the main accretion phase. The adiabatic core formed after the initial collapse (i.e., the first core) experiences further gravitational collapse triggered by dissociation of molecular hydrogen, which leads to the formation of the second core, i.e., the birth of a protostar. The protostar grows in mass as accreting the infalling material from the circumstellar envelope, while the protostar keeps its radius at ~4 R☉ during the main accretion phase. These typical features in the evolution are in good agreement with previous studies. We consider two different initial conditions for the density distribution: homogeneous and hydrostatic cloud cores with the same central density of 1.415 × 10-19 g cm-3 . The homogeneous core has the total mass of 1 M☉ while the hydrostatic core has...

A Radiation Hydrodynamic Model for Protostellar Collapse. II. The Second Collapse and the Birth of a Protostar