Efficiency of secular perturbations and tidal circularization in HEM

Characterize the efficiency of secular perturbations from wide binary companions or planetary companions in driving high-eccentricity tidal migration to very close orbits and quantify the subsequent tidal circularization process for giant planets.

Background

High-eccentricity tidal migration (HEM) can be initiated by secular perturbations from distant companions (stellar or planetary). While such perturbations are plausible triggers, their efficiency in producing very short-period giant planets, and the details of the ensuing tidal circularization, remain poorly constrained.

The authors situate TOI-6038 A b within this context, noting the lack of comprehensive understanding of how secular dynamics and tides jointly shape close-in giant planet populations, especially in systems with wide binary companions.

References

However, the efficiency of these perturbations in driving giant planets to very close orbits and the subsequent circularization process are not yet well understood.

— TOI-6038 A b: A dense sub-Saturn in the transition regime between the Neptunian ridge and savanna  (2501.02272 - Baliwal et al., 4 Jan 2025) in Introduction

The higher misaligned fraction among HJs with stellar companions could therefore reflect either direct EKL excitation or interactions between planets triggered by a companion. Our current data cannot distinguish these possibilities.

— Stellar companions sculpt hot Jupiter formation and spin-orbit evolution  (2609.19249 - Shariat et al., 16 Sep 2026) in Section 5.5, paragraph beginning “A stellar companion could also trigger”

Stellar companion eccentricities and mutual inclinations remain largely unknown, and future astrometric monitoring will be required to constrain their orbits and dynamical implications.

— Stellar companions sculpt hot Jupiter formation and spin-orbit evolution  (2609.19249 - Shariat et al., 16 Sep 2026) in Section 5.5, final paragraph

We leave a detailed analysis of the combined contribution of all environmentally enhanced channels for future work.

— Flyby-induced high-eccentricity migration and the prevalence of hot Jupiters in M67  (2608.24874 - Kontiainen et al., 25 Aug 2026) in Section 3.1, Occurrence Rate Estimates