Thursday, December 8, 2011

1112.1595 (Peter Plavchan et al.)

Stars Don't Eat Their Young Migrating Planets - Empirical Constraints On Planet Migration Halting Mechanisms    [PDF]

Peter Plavchan, Christopher Bilinski
The discovery of "hot Jupiters" very close to their parent stars confirmed that Jovian planets migrate inward via several potential mechanisms. We present empirical constraints on planet migration halting mechanisms. We compute model density functions of close-in exoplanets in the orbital semi-major axis -- stellar mass plane to represent planet migration that is halted via several mechanisms, including the interior 1:2 resonance with the magnetospheric disk truncation radius, the interior 1:2 resonance with the dust sublimation radius, and tidal dissipation. We also compute model density functions for a planet halting distance that has no dependence on stellar mass to represent migration via external perturbers. We fit these model density functions to empirical distributions of known exoplanets and Kepler candidates that orbit interior to 0.1 AU. Migration halting at the interior 1:2 orbital resonance with the magnetospheric disk truncation radius provides the best fit to the empirical distributions that we test. We can rule out migration halting via tidal dissipation and migration halting at the interior 1:2 resonance with the dust disk sublimation radius. Our results favor a weak dependence of the halting distance with stellar mass, and is consistent with the decline in exoplanet frequency towards smaller orbital radii found in the Kepler candidates sample.
View original: http://arxiv.org/abs/1112.1595

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