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

Journal Article · Tue Sep 01 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/702/1/567; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21333814

Vaidya, Bhargav ^[1]; Fendt, Christian; Beuther, Henrik ^[2]

---

1. Member of the International Max Planck Research School for Astronomy and Cosmic Physics at University of Heidelberg, IMPRS-HD, Germany. (Germany)
2. Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

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 {alpha}. The most essential finding is a very high temperature of the inner disk. For e.g., a 10 M{sub sun} protostar with an accretion rate of {approx}10{sup -4} M{sub sun} yr{sup -1}, the disk midplane temperature may reach almost 10{sup 5} K. The disk luminosity in this case is about 10{sup 4} L{sub sun} 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 {alpha} {<=} 1. However, disk stability to fragmentation due to thermal effects and gravitational instability would require a lower {alpha} value. For {alpha} = 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.

• OSTI ID: 21333814
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 702; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
DUSTS
EQUATIONS
GRAVITATIONAL INSTABILITY
HYDRODYNAMICS
LUMINOSITY
MASS
OPACITY
PROTOSTARS
RADIATION PRESSURE
STARS
STEADY-STATE CONDITIONS
SUBLIMATION
TURBULENCE