Bhargav Vaidya et al. 2009 ApJ 702 567 doi:10.1088/0004-637X/702/1/567
Bhargav Vaidya1, Christian Fendt and Henrik Beuther
Show affiliationsWe investigate the structure of accretion disks around massive protostar applying steady state models of thin disks. The thin disk equations are solved with proper opacities for dust and gas taking into account the huge temperature variation along the disk. We explore a wide parameter range concerning stellar mass, accretion rate, and viscosity parameter α. The most essential finding is a very high temperature of the inner disk. For e.g., a 10 M ☉ protostar with an accretion rate of ~10–4 M ☉ yr–1, the disk midplane temperature may reach almost 105 K. The disk luminosity in this case is about 104 L ☉ and, thus, potentially higher than that of a massive protostar. We motivate our disk model with similar hot disks around compact stars. We calculate a dust sublimation radius by turbulent disk self-heating of more than 10 AU, a radius, which is 3 times larger than that caused by stellar irradiation. We discuss implications of this result on the flashlight effect and the consequences for the radiation pressure of the central star. In deference to disks around low-mass protostars, our models suggest rather high values for the disk turbulence parameter α ≤ 1. However, disk stability to fragmentation due to thermal effects and gravitational instability would require a lower α value. For α = 0.1, we find stable disks out to 80 AU. Essentially, our model allows us to compare the outer disk to some of the observed massive protostellar disk sources, and from that, extrapolate the disk structure close to the star which is yet impossible to observe.
accretion, accretion disks; hydrodynamics; methods: analytical; stars: formation; turbulence
Issue 1 (2009 September 1)
Received 2009 April 27, accepted for publication 2009 June 29
Published 2009 August 13
Bhargav Vaidya et al. 2009 ApJ 702 567
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