Venus as an analogue for exoplanet observations

Next-generation instruments will provide the first opportunity to characterize temperate rocky exoplanets orbiting Sun-like stars. Because the surface conditions of rocky exoplanets are much more difficult to constrain than their bulk parameters, these observations will be very challenging. Furthermore, there is a broad range of possible climates for such exoplanets due to difficult-to-constrain parameters like atmosphere mass and composition, surface composition, water abundance, rotation, and obliquity. For example, Venus and Earth have similar bulk parameters but very different climate regimes. Therefore, characterizing a temperate rocky exoplanet means being able to distinguish between Venus-like and Earth-like climates from the planet’s spectrum. I will compare synthetic reflected light spectra of Venus constructed from climate simulations and empirical data. I will discuss the sensitivity of these spectra to model, instrument, and observation parameters, and the conditions required to identify an exoplanet as Venus-like or Earth-like.