Tidal Heating of Exomoons in Resonance and Implications for Detection

Abstract

The habitability of exoplanets can be strongly influenced by the presence of an exomoon, and in some cases the exomoon itself could be a possible place for life to develop. For moons outside of the habitable zone, significant tidal heating may raise their surface temperature enough to be considered habitable. Tidal heating of a moon depends on numerous factors such as eccentricity, semimajor axis, size of parent planet, and presence of additional moons. In this work, we explore the degree of tidal heating possible for multi-moon systems in resonance using a combination of semi-analytic and numerical models. This demonstrates that even for a moon with zero initial eccentricity, when it moves into resonance with an outer moon, it can generate significant eccentricity and associated tidal heating. Depending on the mass ratio of the two moons, this resonance can either be short-lived ($\le 200$ Myr) or continue to be driven by the tidal migration of the moons. This tidal heating can also assist in making the exomoons easier to discover, and we explore two scenarios: secondary eclipses and outgassing of volcanic species. We then consider hypothetical moons orbiting known planetary systems to identify which will be beast suited for finding exomoons with these methods. We conclude with a discussion of current and future instrumentation and missions to better understand how practical it will be to make exomoon discoveries in these ways.

15 pages, 14 figures, updated with minor changes to match version accepted for publication in AJ

References in corpus (8)

• The James Webb Space Telescope
• Detection of Thermal Emission from an Extrasolar Planet
• Tidal Heating of Terrestrial Extra-Solar Planets and Implications for their Habitability
• Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey II: Free-Floating Planet Detection Rates
• The potential for tidally heated icy and temperate moons around exoplanets
• In-flight photometry extraction of PLATO targets: Optimal apertures for detecting extrasolar planets
• Consequences of dynamically unstable moons in extrasolar systems
• Global Chemistry and Thermal Structure Models for the Hot Jupiter WASP-43b and Predictions for JWST

Cited by in corpus (3)

• Precise Transit Photometry Using TESS: Updated Physical Properties for 28 Exoplanets Around Bright Stars
• The "Drake equation" of exomoons -- a cascade of formation, stability and detection
• Life in the dark: Potential urability of moons of rogue planets