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Author Hasegawa, Yasuhiro ♦ Flock, Mario ♦ Turner, Neal J. ♦ Okuzumi, Satoshi
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCRETION DISKS ♦ ANGULAR MOMENTUM ♦ CONFIGURATION ♦ COSMIC DUST ♦ DISTRIBUTION ♦ MAGNETIC FIELDS ♦ MAGNETIC FLUX ♦ MAGNETOHYDRODYNAMICS ♦ PLASMA ♦ PROTOPLANETS ♦ RADIANT HEAT TRANSFER ♦ SIMULATION ♦ SPATIAL RESOLUTION ♦ STARS ♦ STELLAR WINDS ♦ TURBULENCE
Abstract The mechanism of angular momentum transport in protoplanetary disks is fundamental to understanding the distributions of gas and dust in the disks. The unprecedented ALMA observations taken toward HL Tau at high spatial resolution and subsequent radiative transfer modeling reveal that a high degree of dust settling is currently achieved in the outer part of the HL Tau disk. Previous observations, however, suggest a high disk accretion rate onto the central star. This configuration is not necessarily intuitive in the framework of the conventional viscous disk model, since efficient accretion generally requires a high level of turbulence, which can suppress dust settling considerably. We develop a simplified, semi-analytical disk model to examine under what condition these two properties can be realized in a single model. Recent, non-ideal MHD simulations are utilized to realistically model the angular momentum transport both radially via MHD turbulence and vertically via magnetically induced disk winds. We find that the HL Tau disk configuration can be reproduced well when disk winds are properly taken into account. While the resulting disk properties are likely consistent with other observational results, such an ideal situation can be established only if the plasma β at the disk midplane is β {sub 0} ≃ 2 × 10{sup 4} under the assumption of steady accretion. Equivalently, the vertical magnetic flux at 100 au is about 0.2 mG. More detailed modeling is needed to fully identify the origin of the disk accretion and quantitatively examine plausible mechanisms behind the observed gap structures in the HL Tau disk.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-08-10
Publisher Place United States
Journal Astrophysical Journal
Volume Number 845
Issue Number 1


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