On the Formation of Hot Jupiters in Stellar Binaries

TL;DR

This paper investigates how the eccentric Kozai-Lidov mechanism in stellar binaries can produce Hot Jupiters, showing it accounts for about 30% of observed HJs and predicting many planets with specific orbital characteristics.

Contribution

It demonstrates that the EKL mechanism significantly enhances HJ formation efficiency in stellar binaries, aligning with observed spin-orbit angle distributions.

Findings

EKL mechanism increases HJ formation efficiency.

Approximately 30% of observed HJs can originate from this process.

Predicted existence of Jupiter-like planets with eccentric, inclined orbits at several AU.

Abstract

We study the production of Hot Jupiters (HJs) in stellar binaries. We show that the "eccentric Kozai-Lidov" (EKL) mechanism can play a key role in the dynamical evolution of a star-planet-star triple system. We run a large set of Monte Carlo simulations including the secular evolution of the orbits, general relativistic precession, and tides, and we determine the semi-major axis, eccentricity, inclination and spin-orbit angle distributions of the HJs that are produced. We explore the effect of different tidal friction parameters on the results. We find that the efficiency of forming HJs when taking the EKL mechanism into account is higher then previously estimated. Accounting for the frequency of stellar binaries, we find that this production mechanism can account for about 30% of the observed HJ population. Current observations of spin-orbit angles are consistent with this mechanism producing \sim 30% of all HJs, and up to 100% of the misaligned systems. Based on the properties of binaries without a HJ in our simulations, we predict the existence of many Jupiter-like planets with moderately eccentric and inclined orbits and semi-major axes of several AU.