**31st Annual Meeting of the DPS, October 1999**

*Session 10. Planet Formation Posters*

Poster Group I, Monday-Wednesday, October 11, 1999, , Kursaal Center
[Previous] |
[Session 10] |
[Next]

## [10.06] Tidal Interaction between a Planet and a Three-Dimensional Gas Disk

*H. Tanaka (Tokyo Inst. of Tech./SwRI), T. Takeuchi (Stockholm Observatory)*

Linear calculations of the tidal interaction between a
planet and a three-dimensional gas disk has been done to
obtain the tidal torque exerted on the planet and the radial
migration speed of a planet. A rapid migration (~10^{5}
orbit periods) of a planet due to the tidal torque is one of
the serious problems in the theory of planet formation. Most
of the previous studies on the disk-planet interaction
assumed that the disk is infinitely thin (e.g., Ward 1986,
Icarus 67, 164-180; Korycansky & Pollack 1993, Icarus 102,
105-165). But, this assumption would not be valid because a
torque on a planet is exerted mainly by the gas located
within a disk scale-height from the planet. Generally, the
inner disk exerts the positive torque on a planet while the
outer one exerts the negative torque. The sum of these
positive and negative torques leads to the net tidal torque
on the planet. Thus, the three-dimensional effect can
significantly change the net torque and the migration speed.

Recently, the three-dimensional calculations of the
disk-planet tidal interaction were done by some authors
(e.g., Takeuchi & Miyama 1998, Publ.\ Astron.\ Soc.\ Japan
50,141-148; Miyoshi et al. 1999, ApJ 516, 451-464). But they
could not obtain the net torque on a planet, since they
adopted a local approximation. In our calculation, keeping
terms neglected in their calculations, we enabled to obtain
the net tidal torque. Our obtained torque by 3D disk is
about 30% of that by 2D disk for the minimum-mass solar
nebula model. In spite of this reduction due to the
three-dimensional effect, the net torque (or the migration
speed) is still large. The migration problem in planet
formation is still unsolved.

[Previous] |
[Session 10] |
[Next]