2019ApJ...887..244T -
Astrophys. J., 887, 244-244 (2019/December-3)
Exploring the grain properties in the disk of HL Tau with an evolutionary model.
TAPIA C., LIZANO S., SIERRA A., CARRASCO-GONZALEZ C. and BAYONA-BOBADILLA E.
Abstract (from CDS):
We model the ALMA and Very Large Array (VLA) millimeter radial profiles of the disk around HL Tau to constrain the properties of the dust grains. We adopt the disk evolutionary models of Lynden-Bell & Pringle and calculate their temperature and density structure and emission. These disks are heated by the internal viscosity and irradiated by the central star and a warm envelope. We consider a dust size distribution n(a) da ∝ a–3.5 da, and vary the maximum grain size in the atmosphere and the midplane, amax = 100 µm, 1 mm, and 1 cm. We also include dust settling and vary the dust-to-gas mass ratio from 1 to 9 times the ISM value. We find that the models that can fit the observed level of emission along the profiles at all wavelengths have an atmosphere with a maximum grain size amax = 100 µm, and a midplane with amax = 1 cm. The disk substructure, with a deficit of emission in the gaps, can be due to dust properties in these regions that are different from those in the rings. We test an opacity effect (different amax) and a dust mass deficit (smaller dust-to-gas mass ratio) in the gaps. We find that the emission profiles are better reproduced by models with a dust deficit in the gaps, although a combined effect is also possible. These models have a global dust-to-gas mass ratio twice the ISM value, needed to reach the level of emission of the 7.8 mm VLA profile.
Abstract Copyright:
© 2019. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Stellar accretion disks - Protoplanetary disks - Young stellar objects - T Tauri stars - Radiative transfer equation
Simbad objects:
1
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