HR: 10:20h
AN: P51F-01    [PDF]
TI: Time and Length Scales for Planetary and Satellite Gas Disk Clearing
AU: * Estrada, P R
EM: estrada@cosmic.arc.nasa.gov
AF: NASA Ames, MS 245-3, Moffett Field, CA 94035
AU: Mosqueira, I
EM: mosqueir@cosmic.arc.nasa.gov
AF: NASA Ames/SETI Institute, MS 245-3, Moffett Field, CA 94035
AB: Observationally, the maximum ages of T Tauri stars that show evidence for disks is $\sim 10^6-10^7$ years (Strom et al. 1989). On the other hand, a time of $10^6-10^7$ years is needed for giant planet formation through core accretion depending on gas opacity (Pollack et al. 1996; Hubickyj, private communication). One approach to satisfy these constraints involves matching the planetary formation timescale to the unrelated timescale of disk clearing due to turbulent viscosity. In this model, the above agreement of timescales is a coincidence. In contrast, Goodman and Rafikov (2001) considered the possibility that the acoustic waves launched by small (a few Earth mass) planets introduce an effective viscosity that clears the disk in the required timescale. However, such objects are likely to drift in an be lost due to Type I migration (Ward 1997) before the gas disk (where most of the angular momentum of the system is stored) evolves. Mosqueira and Estrada (2003b) (in the context of satellites, but the same argument would apply to planets; see Mosqueira and Estrada, this conference) advanced a related mechanism involving those objects large enough to stall and open a gap in the disk (Rafikov 2002). Here we investigate the possibility that the tidal torque of planets and giant planet satellites clears the gas disk in which they formed in timescales of $\sim 10^6$ years and $\sim 10^5$ years respectively. Also, such a gas clearing mechanism may only be effective to a distance possibly connected with the region where solids are stranded following gas dissipation ($\sim 40$ AU at the edge of the Kuiper belt for the solar system, and the region where regular satellites are found for satellite systems), i.e., outside this region gas would linger and rocky bodies formed there would be removed by gas drag or tidal torques. This work was supported by the National Research Council and a NASA PGG grant.
DE: 6200 PLANETOLOGY: SOLAR SYSTEM OBJECTS (New field)
DE: 6218 Jovian satellites
DE: 6220 Jupiter
DE: 6280 Saturnian satellites
DE: 6299 General or miscellaneous
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting