Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005aas...20716601y&link_type=abstract
American Astronomical Society Meeting 207, #166.01; Bulletin of the American Astronomical Society, Vol. 37, p.1425
Astronomy and Astrophysics
Astronomy
Scientific paper
The formation of planetesimals by gravitational instabilities (GI) of small solids is opposed by turbulent stirring. While traditional GI criteria such as the Roche density are difficult to satisfy, dissipation by gas drag modifies stability properties. The transfer of angular momentum from solids to gas allows dissipative GI at lower densities, higher velocity dispersions, and longer wavelengths. Collapse is slow compared to orbital times, and initially occurs in rings whose non-linear fragmentation determine planetesimal size. Turbulent stirring must still be weak enough that growth is faster than disk lifetimes or particle drift rates. This requires turbulent diffusivities, "alpha" < 10-6}-10{-3, depending on the disk model. Growth depends on the the strength of turbulence, the surface density of self-gravitating solids, and the strength of drag coupling (itself a function of gas density and particle size). Radial variations of the growth rate has implications for the formation of short period extrasolar planets and the outer edge of the primordial Kuiper Belt.
This material is based on work supported by NASA under grant NAG5-11664.
No associations
LandOfFree
Formation of Planetesimals by Dissipative Gravitational Instabilities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Formation of Planetesimals by Dissipative Gravitational Instabilities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Formation of Planetesimals by Dissipative Gravitational Instabilities will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1287761