A Population of Very-Hot Super-Earths in Multiple-Planet Systems Should be Uncovered by Kepler

TL;DR

Simulations suggest that very-hot super-Earths in multiple-planet systems, especially around stars with low dissipation, should be detectable by Kepler, contributing significantly to the overall super-Earth population.

Contribution

This study introduces a simulation-based approach to predict the existence and detectability of very-hot super-Earths in Kepler data, highlighting their expected prevalence.

Findings

Orbital period distribution matches models with stellar Q_* between 10^6 and 10^7.

Very-hot super-Earths can survive tidal disruption for a significant part of stellar lifetimes.

Such super-Earths are likely common in multiple-planet systems around low-dissipation stars.

Abstract

We simulate a Kepler-like observation of a theoretical exoplanet population and we show that the observed orbital period distribution of the Kepler giant planet candidates is best matched by an average stellar specific dissipation function Q_* in the interval 10^6 ~< Q_* ~< 10^7. In that situation, the few super-Earths that are driven to orbital periods P < 1 day by dynamical interactions in multiple-planet systems will survive tidal disruption for a significant fraction of the main-sequence lifetimes of their stellar hosts. Consequently, though these very-hot super-Earths are not characteristic of the overall super-Earth population, their substantial transit probability implies that they should be significant contributors to the full super-Earth population uncovered by Kepler. As a result, the CoRoT-7 system may be the first representative of a population of very-hot super-Earths that we suggest should be found in multiple-planet systems preferentially orbiting the least-dissipative stellar hosts in the Kepler sample.