Print Email Facebook Twitter Tidally heated exomoons around gas giants Title Tidally heated exomoons around gas giants Author Rovira Navarro, M. (TU Delft Astrodynamics & Space Missions; NIOZ Royal Netherlands Institute for Sea Research) van der Wal, W. (TU Delft Physical and Space Geodesy; TU Delft Astrodynamics & Space Missions) Steinke, T. (TU Delft Astrodynamics & Space Missions) Dirkx, D. (TU Delft Astrodynamics & Space Missions) Date 2021 Abstract Thousands of exoplanets have been discovered; however, the detection of exomoons remains elusive. Tidally heated exomoons have been proposed as candidate targets for observation; vigorous tidal dissipation can raise the moon's surface temperature, making direct imaging possible, and cause widespread volcanism that can have a signature in transits. We assess whether the required amounts of tidal dissipation can be attained and how long it can be sustained. In a first step, we look at the thermal state of a super-Io for different orbital configurations. We show that close-in exomoons with moderate (e ≈ eIo) to high (e ≈ 0.1) orbital eccentricities can feature surface heat fluxes 1-3 orders of magnitude higher than that of Io if heat transfer is dominated by heat piping or the moon has a magma ocean. In a second step, we investigate the longevity of a super-Io. The free eccentricity of an isolated close-in exomoon is quickly dampened due to tides; high orbital eccentricities can be maintained if the moon is in a mean-motion resonance with another moon and the planet is highly dissipative. However, this scenario leads to fast orbital migration. For a Mars-sized exomoon, we find that tides alone can raise the surface temperatures to more than 400 K for 10 million yr, and surface heat fluxes higher than that of Io can be maintained for billions of years. Such tidally active bodies are expected to feature more vigorous volcanic activity than Io. The material outgassed via volcanism might be detected in transits. To reference this document use: http://resolver.tudelft.nl/uuid:0dc1810b-5412-4535-af72-169005f268bc DOI https://doi.org/10.3847/PSJ/abf6cb Source Planetary Science Journal, 2 (3) Part of collection Institutional Repository Document type journal article Rights © 2021 M. Rovira Navarro, W. van der Wal, T. Steinke, D. Dirkx Files PDF Rovira_Navarro_2021_Plane ... _2_119.pdf 2.8 MB Close viewer /islandora/object/uuid:0dc1810b-5412-4535-af72-169005f268bc/datastream/OBJ/view