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Title: Radiation-driven warping of circumbinary disks around eccentric young star binaries

We study a warping instability of a geometrically thin, non-self-gravitating, circumbinary disk around young binary stars on an eccentric orbit. Such a disk is subject to both the tidal torques due to a time-dependent binary potential and the radiative torques due to radiation emitted from each star. The tilt angle between the circumbinary disk plane and the binary orbital plane is assumed to be very small. We find that there is a radius within/beyond which the circumbinary disk is unstable to radiation-driven warping, depending on the disk density and temperature gradient indices. This marginally stable warping radius is very sensitive to viscosity parameters, a fiducial disk radius and the temperature measured there, the stellar luminosity, and the disk surface density at a radius where the disk changes from optically thick to thin for the irradiation from the central stars. On the other hand, it is insensitive to the orbital eccentricity and binary irradiation parameter, which is a function of the binary mass ratio and luminosity of each star. Since the tidal torques can suppress the warping in the inner part of the circumbinary disk, the disk starts to be warped in the outer part. While the circumbinary disks are mostmore » likely to be subject to the radiation-driven warping on an AU to kilo-AU scale for binaries with young massive stars more luminous than 10{sup 4} L {sub ☉}, the radiation-driven warping does not work for those around young binaries with the luminosity comparable to the solar luminosity.« less
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Korea Astronomy and Space Science Institute, Daedeokdaero 776, Yuseong, Daejeon 305-348 (Korea, Republic of)
  2. Faculty of Engineering, Hokkai-Gakuen University, Toyohira-ku, Sapporo 062-8605 (Japan)
  3. Faculty of Management Information, Yamanashi Gakuin University, Kofu, Yamanashi 400-8575 (Japan)
Publication Date:
OSTI Identifier:
22370070
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 797; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BINARY STARS; COMPARATIVE EVALUATIONS; DENSITY; EMISSION; HYDRODYNAMICS; INSTABILITY; IRRADIATION; LUMINOSITY; MASERS; MASS; ORBITS; PROTOPLANETS; TEMPERATURE GRADIENTS; TIME DEPENDENCE