Volcanic Exoplanet Surfaces

Abstract

ABSTRACT Recent measurements of the reflection of the surface of a lava world provides an unprecedented opportunity to investigate different stages of rocky planet evolution. The spectral features of the surfaces of rocky exoplanets give insights into their evolution and inner workings. However, no data base exists yet that contains spectral reflectivity and emission of a wide range of potential volcanic exoplanet surface materials. Here, we first synthesized 16 possible exoplanet surfaces, spanning a wide range of chemical compositions based on potential mantle material of volcanic exoplanets guided by the metallicity of different host stars. Then, we measured their infrared reflection spectrum (2.5–28 μm), from which we obtained their emission spectra, and established the link between the composition and a strong spectral feature at 8 μm, the Christiansen feature (CF). Our analysis suggests a new multicomponent composition relationship with the CF as well as a correlation with the silica content of the exoplanet mantle. We also report the mineralogies of these materials, as possibilities for volcanic worlds. This data base is a tool to aid in the interpretation of future spectra of volcanic and lava worlds that will be collected by the James Webb Space Telescope and other missions.