Cornell scientists are pioneering a library of spectral signatures based on basalt rock samples to help analyze the composition of rocky exoplanets and detect potential signs of water. Led by Esteban Gazel, professor of engineering at Cornell, and Emily First, assistant professor at Macalester College, the research focuses on studying basalts, which are formed from mantle melts and are prevalent across planetary bodies, including Earth, Mars, and the Moon. Since basalts can indicate geologic history, analyzing their spectral characteristics could help scientists interpret surface conditions on exoplanets and assess the likelihood of water presence.

To build this spectral library, researchers measured the emissivity of 15 basaltic samples, establishing signatures the James Webb Space Telescope (JWST) could detect in the mid-infrared range. These spectra can reveal whether basalts on exoplanets have interacted with water, which transforms them into hydrated minerals like amphibole or serpentine. Such minerals are distinguishable in the infrared spectrum, potentially offering evidence of past or present water.

As a testbed, the research team modeled spectral data for the super-Earth exoplanet LHS 3844b, located 48 light-years away, using tools initially designed for studying icy moons. This model helps simulate how various basaltic surfaces might appear to the JWST. However, the focus wasn’t specifically on LHS 3844b but on building a framework to apply across a range of rocky exoplanets. Gazel’s team hopes this library will aid in interpreting JWST data, providing insights into planetary surfaces and conditions, such as mineralogy and chemical composition, which could ultimately reveal traces of water beyond our solar system.

This research represents a significant step in moving from single data points to complex, multi-component analyses, allowing for a deeper understanding of rocky exoplanets’ geological diversity and habitability.