Quick search Find article
Quick search
Find article

ACCRETION DISKS AROUND MASSIVE STARS: HYDRODYNAMIC STRUCTURE, STABILITY, AND DUST SUBLIMATION

FREE ISSUE

Bhargav Vaidya1, Christian Fendt and Henrik Beuther

Show affiliations


We 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.


Keywords

accretion, accretion disks; hydrodynamics; methods: analytical; stars: formation; turbulence


Dates

Issue 1 (2009 September 1)

Received 2009 April 27, accepted for publication 2009 June 29

Published 2009 August 13



View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.