Can information theory provide insights into whether exoplanets are habitable? In a recent peer-reviewed study, a team led by AER Senior Research Associate Sara Vannah applied information theory to a range of simulated exoplanet transmission spectra as a diagnostic tool to search for potential signatures of life on Earth-analog planets. They tested the algorithms on three epochs of evolution for Earth-like planets orbiting a range of host stars. The James Webb Space Telescope and upcoming ground- and space-based missions promise to achieve sufficient high-resolution data that information theory can be applied to assess habitability. Their approach provides a framework and a tool for observers to assess whether an exoplanet shows signs of habitability.
Figure: The Jensen-Shannon divergence density (𝛿𝐽𝑆,𝜈), a measure of the difference in information content between two spectra, can be used to search for signatures of life in exoplanet atmospheres. Here, we show the 𝛿𝐽𝑆,𝜈 comparing a series of simulated Earth-like planets orbiting different host stars to a model of modern Earth. Each row represents Earth-like planets orbiting a different spectral class of host star; each column shows a different wavelength band with higher magnification in the near-infrared to better show the absorption features in that range.
Citation: An Information Theory Approach to Identifying Signs of Life on Transiting Planets
S. Vannah, M. Gleiser, L. Kaltenegger
Monthly Notices of the Royal Astronomical Society: Letters, 528(1), L4-L9, 2024.