skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Dynamics of circumstellar disks. III. The case of GG Tau A

Abstract

Here, we present two-dimensional hydrodynamic simulations using the Smoothed Particle Hydrodynamic code, VINE, to model a self-gravitating binary system. We model configurations in which a circumbinary torus+disk surrounds a pair of stars in orbit around each other and a circumstellar disk surrounds each star, similar to that observed for the GG Tau A system. We assume that the disks cool as blackbodies, using rates determined independently at each location in the disk by the time dependent temperature of the photosphere there. We assume heating due to hydrodynamical processes and to radiation from the two stars, using rates approximated from a measure of the radiation intercepted by the disk at its photosphere.

Authors:
ORCiD logo [1];  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. di Padova, Padova (Italia)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1329905
Report Number(s):
LA-UR-16-23283
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 827; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; accretion; accretion disks; binaries: general; protoplanetary disks; stars: formation; stars: variables: T Tauri; Herbig Ae/Be

Citation Formats

Nelson, Andrew F., and Marzari, Francesco. Dynamics of circumstellar disks. III. The case of GG Tau A. United States: N. p., 2016. Web. doi:10.3847/0004-637X/827/2/93.
Nelson, Andrew F., & Marzari, Francesco. Dynamics of circumstellar disks. III. The case of GG Tau A. United States. doi:10.3847/0004-637X/827/2/93.
Nelson, Andrew F., and Marzari, Francesco. 2016. "Dynamics of circumstellar disks. III. The case of GG Tau A". United States. doi:10.3847/0004-637X/827/2/93. https://www.osti.gov/servlets/purl/1329905.
@article{osti_1329905,
title = {Dynamics of circumstellar disks. III. The case of GG Tau A},
author = {Nelson, Andrew F. and Marzari, Francesco},
abstractNote = {Here, we present two-dimensional hydrodynamic simulations using the Smoothed Particle Hydrodynamic code, VINE, to model a self-gravitating binary system. We model configurations in which a circumbinary torus+disk surrounds a pair of stars in orbit around each other and a circumstellar disk surrounds each star, similar to that observed for the GG Tau A system. We assume that the disks cool as blackbodies, using rates determined independently at each location in the disk by the time dependent temperature of the photosphere there. We assume heating due to hydrodynamical processes and to radiation from the two stars, using rates approximated from a measure of the radiation intercepted by the disk at its photosphere.},
doi = {10.3847/0004-637X/827/2/93},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 827,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 4works
Citation information provided by
Web of Science

Save / Share:
  • Photoevaporation by stellar ionizing radiation is believed to play an important role in the dispersal of disks around young stars. The mass-loss model for dust-free disks developed by Hollenbach et al. is currently regarded as the conventional one and has been used in a wide variety of studies. However, the rate in this model was derived using the crude so-called 1+1D approximation of ionizing radiation transfer, which assumes that diffuse radiation propagates in a direction vertical to the disk. In this study, we revisit the photoevaporation of dust-free disks by solving the two-dimensional axisymmetric radiative transfer for steady-state disks. Unlikemore » that solved by the conventional model, we determine that direct stellar radiation is more important than the diffuse field at the disk surface. The radial density distribution at the ionization boundary is represented by a single power law with index -3/2 in contrast to the conventional double power law. For this distribution, the photoevaporation rate from the entire disk can be written as a function of the ionizing photon emissivity {Phi}{sub EUV} from the central star and the disk outer radius r{sub d} as follows: M-dot{sub PE} = 5.4 x 10{sup -5} ({Phi}{sub EUV}/10{sup 49} s{sup -1}){sup 1/2} (r{sub d}/1000 AU){sup 1/2} M{sub Sun} yr{sup -1}. This new rate depends on the outer disk radius rather than on the gravitational radius as in the conventional model, because of the enhanced contribution to the mass loss from the outer disk annuli. In addition, we discuss its applications to present-day as well as primordial star formation.« less
  • Circumstellar particle disks appear to be a common phenomenon; however, their properties vary greatly. Models of the evolution of such systems focus on internal mechanisms such as interparticle collisions and Poynting-Robertson drag. Herein it is shown that 'sandblasting' by interstellar dust can be an important and even dominant contributor to the evolution of circumstellar particle disks. Stars spend up to about 3 percent of their main-sequence lifetimes within atomic clouds. Among an IRAS sample of 21 nearby main-sequence A stars, beta Pictoris has the brightest disk; it also possesses the smallest random velocity and therefore the slowest predicted erosion rate.more » 35 refs.« less
  • A survey using data from the International Ultraviolet Explorer (IUE) of previously known B and A shell stars with IRAS detections has resulted in the identification of three stars, HD 93563, Sigma Her, and 51 Oph, which have spectral signatures of infalling circumstellar plasma similar to Beta Pic. Two of these systems have infrared flux distributions indicating the presence of circumstellar dust disks, while the other, HD 93563, has an infrared excess consistent with free-free emission from the plasma envelope. With the identification of three such systems, it is clear that infalling circumstellar plasma is more common than previously anticipatedmore » among late-type B shell stars. The absence of dust in one system, HD 93563, suggests that infalling plasma in these stars, and possibly also in Beta Pic itself, may not be due to either erosion of a dust disk or to high cometary bombardment rates, but may instead be linked to stellar activity. 37 refs.« less
  • Results are presented from a survey for 1.3 mm radiation toward 86 stars in the Taurus-Auriga dark clouds, including classical T Tauri stars, stars in T associations, and a few weak emission-line stars or naked T Tauri stars. The results show that 42 percent of the stars have detectable emission from small particles. The aggregate particle masses are found to be between 0.00001 and 0.01 solar mass, suggesting total disk masses between 0.001 and 1 solar mass. For several source between 1.3 and 2.7 mm, the spectral indices indicate that the particle emissivities are weaker functions of frequency, compared tomore » the usual case of interstellar grains. Particle growth via adhesion in the dense disks is proposed to explain this result. The results show that disks more massive than the minimum mass of the protosolar system commonly accompany the birth of solar-mass stars, indicating that planetary systems are probably common in the Galaxy. 59 refs.« less
  • Recent theoretical advances in our understanding of the dynamics of circumstellar accretion disks are reviewed. Of particular importance are developments regarding angular momentum transport processes in disks. It has recently been shown through direct numerical simulation that vertical convection results in inward transport, and thus is unlikely to serve as a source of anomalous viscosity. More importantly, these results have been generalized to demonstrate that any form of hydrodynamic turbulence in which velocity fluctuations do not extract both energy and angular momentum from the mean shear flow will be associated with inward angular momentum transport. In fact, the analysis predictsmore » that nonlinear shear instabilities are absent in Keplerian disks, a result which has been confirmed through direct numerical simulation. The important role that MHD turbulence driven by the Balbus-Hawley (BH) instability plays in outward angular momentum transport is emphasized, especially regarding the implications for the production of MHD winds from disks. A detailed understanding of the dynamical interaction between an accretion disk and the magnetosphere of the central object will be crucial to understanding accretion from disks in general.« less