Detecting Volcanism on Extrasolar Planets

TL;DR

This paper models volcanic eruptions on Earth-like exoplanets to determine if sulfur dioxide signatures from eruptions can be remotely detected, aiding the identification of active volcanism on transiting rocky exoplanets.

Contribution

It introduces a model for volcanic eruptions on exoplanets and analyzes the detectability of sulfur dioxide signatures in their spectra.

Findings

Sulfur dioxide from eruptions can be detected in secondary eclipse spectra.

Detection is more feasible for nearby stars with ground-based telescopes.

Close-in habitable zone planets have higher transit probabilities.

Abstract

The search for extrasolar rocky planets has already found the first transiting rocky super-Earth, Corot 7b, with a surface temperature that allows for magma oceans. Here we ask if we could distinguish rocky planets with recent major volcanism by remote observation. We develop a model for volcanic eruptions on an Earth-like exoplanet based on the present day Earth, derive the observable features in emergent and transmission spectra for multiple scenarios of gas distribution and cloudcover. We calculate the observation time needed to detect explosive volcanism on exoplanets in primary as well as secondary eclipse and discuss the likelihood of observing volcanism on transiting Earth to super-Earth sized exoplanets. We find that sulfur dioxide from large explosive eruptions does present a spectral signal that is remotely detectable especially for secondary eclipse measurements around the closest stars using ground based telescopes, and report the frequency and magnitude of the expected signatures. Transit probability of planet in the habitable zone decreases with distance to the host star, making small, close by host stars the best targets