9. Star formation

Cute sequence of star formation stages

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

The radio picture from the SKA

Binary Star Formation

During star formation, gravitational collapse forms a proto-star.
The released gravitational energy at first goes into
dissociating H2 and ionizing H and He.

Bate movies

Assume collapse from ∞ to the protostar radius, Rp:

α GM 2/Rp ≈ (M/mH)(H2 /2 + H + 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.

Rp/Rs ≈ 50 (M/Ms) /(1 − 0.2X )

Hayashi track:
Te ≈ 2600 μ13/51 (M/Ms)7/51 (L/Ls)1/102 K.

Henyey track:
LM 22/5Te4/5.