In the realm of energy research, a team of scientists from the University of Bern, the University of Geneva, and the University of Nantes have turned their attention not to Earth’s energy systems, but to the fascinating TRAPPIST-1 planetary system. Their work, published in the journal Astronomy & Astrophysics, explores the role of tidal heating in these distant worlds and its potential implications for their energy budgets and habitability.
The researchers, led by Emeline Bolmont from the University of Bern, have developed a method to estimate the tidal heating profiles of the TRAPPIST-1 planets. Tidal heating is a process by which gravitational interactions between a planet and its host star or other celestial bodies generate heat within the planet. This phenomenon is well-known in our solar system, with Jupiter’s moon Io being a prime example of a tidally heated world.
The team’s approach leverages a known formulation for synchronously rotating planets on low-eccentricity orbits, focusing on how the internal structure of these planets influences their tidal heating profiles. They considered a range of internal structures, from volatile-poor planets with silicate-rock compositions to those with varying core sizes. For each structure, they calculated the degree-two gravitational Love number, a measure of a planet’s internal flexibility, and the corresponding tidal heating profiles.
The researchers found that the tidal heat flux for the innermost planets, TRAPPIST-1b and c, can exceed that of Io, with uncertainties primarily driven by the planets’ orbital eccentricities. These high fluxes may be detectable with the James Webb Space Telescope (JWST), providing an opportunity to test their predictions. For the outermost planets, TRAPPIST-1f to g, the tidal flux remains below Earth’s geothermal flux, suggesting that tidal heating is unlikely to be the dominant energy source.
However, for planets d and e, tidal heating likely dominates their heat budget. This could drive intense volcanic and tectonic activity, potentially enhancing their habitability prospects. The researchers note that their estimates are conservative, as they assume sub-solidus temperatures profiles that are decoupled from interior heat production. Therefore, the actual tidal heating could be even higher.
While this research may seem far removed from Earth’s energy sector, it offers valuable insights into the diverse energy sources that can shape planetary environments. Understanding these processes can help inform our search for habitable worlds and broaden our perspective on the energy dynamics that drive planetary systems. Moreover, the methods developed in this study could potentially be applied to better understand tidal heating in our own solar system, with implications for the energy budgets of moons like Europa and Enceladus, which are also of interest for their potential habitability.
This article is based on research available at arXiv.