Steady-state Planet Migration by the Kozai-Lidov Mechanism in Stellar Binaries
Abstract
We study the steady-state orbital distributions of giant planets migrating through the combination of the Kozai-Lidov (KL) mechanism due to a stellar companion and friction due to tides raised on the planet by the host star. We run a large set of Monte Carlo simulations that describe the secular evolution of a star-planet-star triple system including the effects from general relativistic precession, stellar and planetary spin evolution, and tides. Our simulations show that KL migration produces Hot Jupiters (HJs) with semi-major axes that are generally smaller than in the observations and they can only explain the observations if the following are both true: (1) tidal dissipation at high eccentricities is at least ~150 times more efficient than the upper limit inferred from the Jupiter-Io interaction; (2) highly eccentric planets get tidally disrupted at distances >~ 0.015 AU. Based on the occurrence rate and semi-major axis distribution of HJs, we find that KL migration in stellar binaries can produce at most ~20% of the observed HJs. Almost no intermediate-period (semi-major axis ~0.1 -2 AU) planets are formed by this mechanism—migrating planets spend most of their lifetimes undergoing KL oscillations at large orbital separations (>2 AU) or as HJs.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2015
- DOI:
- 10.1088/0004-637X/799/1/27
- arXiv:
- arXiv:1405.0280
- Bibcode:
- 2015ApJ...799...27P
- Keywords:
-
- binaries: general;
- planetary systems;
- planets and satellites: dynamical evolution and stability;
- planets and satellites: formation;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 29 pages, 11 figures. ApJ, in press