Outline

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, 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 − 0.2X )

Hayashi track:
T_e ≈ 2600 μ^13/51 (M/M_s)^7/51 (L/L_s)^1/102 K.

Henyey track:
L ∝ M ^22/5T_e^4/5.