# On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

## TL;DR

This study explores how secular high-eccentricity migration in stellar triple systems can form hot Jupiters, finding a modest increase in efficiency over binary systems and similar orbital characteristics.

## Contribution

It demonstrates that stellar triples can produce hot Jupiters more efficiently than binaries, with specific orbital configurations influencing formation likelihood.

## Key findings

- Higher HJ formation efficiency in triples than binaries
- Formed HJs have similar properties to those in binaries
- No significant warm Jupiters formed in simulations

## Abstract

Hot Jupiters (HJs) are Jupiter-like planets orbiting their host star in tight orbits of a few days. They are commonly believed not to have formed in situ, requiring inwards migration towards the host star. One of the proposed migration scenarios is secular high-eccentricity or high-$e$ migration, in which the orbit of the planet is perturbed to high eccentricity by secular processes, triggering strong tidal evolution and orbital migration. Previous theoretical studies have considered secular excitation in stellar binaries. Recently, a number of HJs have been observed in stellar triple systems. In the latter, the secular dynamics are much richer compared to stellar binaries, and HJs could potentially be formed more efficiently. Here, we investigate this possibility by modeling the secular dynamical and tidal evolution of planets in two hierarchical configurations in stellar triple systems. We find that the HJ formation efficiency is higher compared to stellar binaries, but only by at most a few tens of per cent. The orbital properties of the HJs formed in the simulations are very similar to HJs formed in stellar binaries, and similarly to studies of the latter we find no significant number of warm Jupiters. HJs are only formed in our simulations for triples with specific orbital configurations, and our constraints are approximately consistent with current observations. In future, this allows to rule out high-$e$ migration in stellar triples if a HJ is detected in a triple grossly violating these constraints.