Presentation #309.04 in the session Exoplanet-Star Interactions.
Lava planets are a class of rocky exoplanets that orbit very close to their star where their molten surfaces are hot enough to vaporize rocks. This results in a thin mineral vapour atmosphere that may be detectable due to lava planets’ high signal-to-noise ratio. The extreme atmosphere on a lava planet is expected to be non-global which makes it difficult for general circulation models to handle. Much of the atmospheric modelling on lava planets either fundamentally focus on radiative transfer or hydrodynamics. For this work, we couple the two processes to simulate the flow and observability of the silicate atmosphere on lava planet K2-141b. Because SiO has very strong UV spectral features, we find that UV radiative heating and cooling interact to keep atmospheric temperature nearly constant horizontally. A strong negative lapse rate induced by UV absorption at high altitudes greatly increases wind speeds which in turn, cools the overall atmosphere. We use our results to simulate transit and emission spectroscopy. At transit, the biggest spectral features lie in the UV band, but the atmosphere is too thin to produce a signal detectable with current or near-term instruments. Simulated emission spectra at eclipse are more promising and show strong signals detectable with Spitzer and the James Webb Space Telescope.