English

Steady-state planet migration by the Kozai-Lidov mechanism in stellar binaries

Earth and Planetary Astrophysics 2015-01-15 v2

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: (i) tidal dissipation at high eccentricities is at least 150\sim 150 times more efficient than the upper limit inferred from the Jupiter-Io interaction; (ii) highly eccentric planets get tidally disrupted at distances 0.015\gtrsim 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%\sim 20\% of the observed HJs. Almost no intermediate-period (semi-major axis 0.12\sim0.1-2 AU) planets are formed by this mechanism - migrating planets spend most of their lifetimes undergoing KL oscillations at large orbital separations (>2>2 AU) or as Hot Jupiters.

Keywords

Cite

@article{arxiv.1405.0280,
  title  = {Steady-state planet migration by the Kozai-Lidov mechanism in stellar binaries},
  author = {Cristobal Petrovich},
  journal= {arXiv preprint arXiv:1405.0280},
  year   = {2015}
}

Comments

29 pages, 11 figures. ApJ, in press; accepted November 3, 2014. Section 6.3 added showing the effect of the host star's spin period