Constraining Tidal Dissipation in Stars from The Destruction Rates of Exoplanets

TL;DR

This study uses the distribution of exoplanets in circular orbits to constrain stellar tidal dissipation efficiency, finding that the tidal quality factor Q* is likely above 10^7, indicating less efficient dissipation than previously thought.

Contribution

It provides new constraints on the stellar tidal quality factor Q* using exoplanet orbital data, highlighting differences from binary star systems.

Findings

Q* is likely greater than 10^7 at 99% confidence

Current exoplanet data is inconsistent with Q*<10^7

Different dissipation mechanisms may operate in star-star versus star-planet systems

Abstract

We use the distribution of extrasolar planets in circular orbits around stars with surface convective zones detected by ground based transit searches to constrain how efficiently tides raised by the planet are dissipated on the parent star. We parameterize this efficiency as a tidal quality factor (Q*). We conclude that the population of currently known planets is inconsistent with Q*<10^7 at the 99% level. Previous studies show that values of Q* between 10^5 and 10^7 are required in order to explain the orbital circularization of main sequence low mass binary stars in clusters, suggesting that different dissipation mechanisms might be acting in the two cases, most likely due to the very different tidal forcing frequencies relative to the stellar rotation frequency occurring for star--star versus planet--star systems.