Tidal decay and circularization of the orbits of short-period planets

TL;DR

This paper investigates how tidal forces influence the long-term evolution of short-period planetary orbits, focusing on decay and circularization through numerical and analytical methods.

Contribution

It introduces a comprehensive analysis of tidal effects on orbital evolution, including the critical eccentricity where stellar tides dominate over planetary tides.

Findings

Stellar tides become dominant at high eccentricities.

Orbital decay and circularization timescales vary with planetary and stellar properties.

Critical eccentricity thresholds for tidal dominance are identified.

Abstract

We analyze the long-term tidal evolution of a single-planet system through the use of numerical simulations and averaged equations giving the variations of semi-major axis and eccentricity of the relative orbit. For different types of planets, we compute the variations due to the planetary and stellar tides. Then, we calculate the critical value of the eccentricity for which the stellar tide becomes dominant over the planetary tide. The timescales for orbital decay and circularization are also discussed and compared.