Star Formation and Bipolar Flows

Observations of molecular outflows from regions of star formation show that they cannot be radiatively driven ((Ṁv) mol ≥ 10 2 – 10 3 (L./c)). The thrust observed to be associated with the smaller scale ionized outflows is also incapable of driving the molecular gas ((Ṁv) ion ≃ (L./c), Persson et al 1984). The results may be explained if bipolar flows are hydromagnetic winds from molecular disks around protostars. These winds carry off disk rotational energy (observed as the mechanical energy of the outflows) and angular momentum (observed when rotation of the outflowing gas is found), which drives an accretion flow through it and onto the protostellar core (Pudritz 1985, Pudritz and Norman 1983, 1986). Therefore star formation and bipolar outflows occur simultaneously when magnetized, rotating disks are the source of activity.