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Gravitational instability in two-phase disks and the origin of the moon

Thompson, Christopher and Stevenson, David J. (1988) Gravitational instability in two-phase disks and the origin of the moon. Astrophysical Journal, 333 . pp. 452-481. ISSN 0004-637X. doi:10.1086/166760.

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Two-phase disks may be gravitationally unstable at temperatures or surface densities at which a disk composed of either single phase would be highly stable. It is argued that two-phase disks can achieve a marginally unstable state (in addition to a highly unstable state that leads to fragmentation), limited by the ability of the photosphere to radiate the energy dissipated in the disk. A self-consistent prescription for the viscosity induced by the slow instabilities is provided. Two-phase disks are more centrally condensed than single-phase disks, and their secular cooling time may be comparable to their spreading time. A circumterrestrial disk of sufficient mass to form the moon provides a detailed example of all the preceding points. Its stability, structure, and dynamical evolution are investigated, and it is concluded that its spreading time is short (about ~100 yr); the moon is formed molten, or partially molten; the moon's initial orbit lies in the earth's equatorial plane; and only a small fraction of the disk mass is lost in a wind, although this may represent a substantial fraction of volatiles. Most of these conclusions are independent of how the disk was formed, e.g., from a giant impact.

Item Type:Article
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Stevenson, David J.0000-0001-9432-7159
Additional Information:© 1988 The American Astronomical Society. Received 1986 August 28; accepted 1988 March 22. We acknowledge conversations with P. Goldreich and W. Ward. This work was initiated while C. T. held a Caltech Summer Undergraduate Research Fellowship; we are grateful to the SURF program for its support. D. J. S. acknowledges support from NASA grant NAGW 185.
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Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Subject Keywords:Moon - planets; formation
Record Number:CaltechAUTHORS:20130621-152608690
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39035
Deposited On:21 Jun 2013 22:51
Last Modified:09 Nov 2021 23:42

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