Cute sequence of star formation stages

More detailed generic powerpoint from Seminar in Theoretical Astrophysics, "Greatest hits"

The radio picture from the SKA

During star formation, gravitational collapse forms a proto-star.

The released gravitational energy at first goes into

dissociating H_{2} and ionizing H and He.

Assume collapse from ∞ to the protostar radius, *R*_{p}:

*α GM*^{ 2}/*R*_{p} ≈
(*M*/*m*_{H})(*Xχ*_{H2} /2 +
*Xχ*_{H} + *Yχ*_{He} /4),

where *α* is a number of order unity depending on radiative losses.

Remember that for polytropes
Ω = −[3/(5 − *n*)] *GM*^{ 2}/*R*, and
for an ideal gas *n* = 1.5.

*R*_{p}/*R*_{s} ≈ 50
(*M*/*M*_{s}) /(1 − 0.2*X* )

Hayashi track:

*T*_{e} ≈ 2600 *μ*^{13/51}
(*M*/*M*_{s})^{7/51}
(*L*/*L*_{s})^{1/102} K.

Henyey track:

*L* ∝ *M*^{ 22/5}*T*_{e}^{4/5}.