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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