Star formation in rotating, magnetized molecular disks

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/163227· OSTI ID:5375280

Pudritz, R E

The discovery of dense, rotating molecular disks associated with protostars and bipolar outflows suggests that massive (M/sub d/approx.10/sup 1.5/ M/sub sun/) objects have not shed their excessive (happrox.10/sup 22/ cm/sup 2/ s/sup -1/) angular momentum by the time protostellar activity begins. This paper presents a theory for star formation in rotating disks in which accretion onto the protostellar core produces FUV radiation which heats the disk surfaces out to large radii. A hydromagnetic wind results in which heated gas is driven out along field lines which thread the disk and are aligned with the disk rotation axis. For accretion luminosities of 4 x 10/sup 37/ ergs s/sup -1/, a highly ionized flow inside 10/sup 15/ cm with M/sub ion/ up to 10/sup -6/ M/sub sun/ yr/sup -1/ is expected, and a much more massive, neutral component carrying M/sub w/ = 10/sup 22/ g s/sup -1/ from disk radii r>10/sup 15/ cm. Terminal wind speeds of 50 km s/sup -1/ are achieved in this bipolar outflow. The centrifugally driven wind removes angular momentum from the disk at rates high enough to brake it down to protostellar specific values in 10/sup 5/ yr. The wind drives an accretion rate through the disk at rates which are consistent with the accretion luminosity. This global analysis of star formation in a rotating, magnetized disk offers a unifying scheme for understanding both star formation and bipolar outflows. The disks are ''flywheels'' that store rotational energy which is released at a rate dictated self-consistently by the rate at which accretion onto the central protostellar core occurs. The disks in which massive stars form are predicted to be dense (10/sup 8/ cm/sup -3/) and have rotation speeds of 4 km s /sup -1/, scales of order 5 x 10/sup 16/ cm, masses of order 10/sup 2/ M/sub sun/, and axial ratios of 0.2.

• Research Organization: Astronomy Department and Space Sciences Laboratory, University of California, Berkeley
• OSTI ID: 5375280
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 293:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR MOMENTUM
ELECTROMAGNETIC RADIATION
FAR ULTRAVIOLET RADIATION
FLUID MECHANICS
HYDRODYNAMICS
INTERSTELLAR GRAINS
IONIZATION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
MOTION
PARTICLES
PROTOSTARS
RADIATIONS
ROTATION
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STELLAR ACTIVITY
STELLAR WINDS
TORQUE
ULTRAVIOLET RADIATION