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Exploring the Habitability and Biosignatures of Extrasolar Terrestrial Planets

This interdisciplinary team will build on the existing models and tools developed by the NAI’s Virtual Planetary Laboratory (VPL) to further explore the potential diversity of other worlds, and to inform strategies for extrasolar terrestrial planet characterization. The VPL will explore the evolution and limits of terrestrial planet habitability and continue work to identify planetary biosignatures for a range of planetary masses, environmental compositions and metabolisms. Ultimately, this group seeks to determine the likely detectability of these planetary characteristics in disk-averaged planetary spectra.

We will expand the VPL to incorporate a time dependent, 3-dimensional description of terrestrial planet environments by synthesizing an existing paleoclimate General Circulation Model (GCM) with the VPL’s existing planetary spectral modeling capability. Our sophisticated radiative transfer model will be upgraded to improve its speed, and incorporated into the GCM. This tool will be used to simulate terrestrial planets, including those with masses significantly larger than Earth’s, and to explore the evolution of planetary environments over different time-scales, or around highly variable stars. To assess the detectability of biosignatures in the spectra of these synthetic environments, the radiative transfer model will generate spatially-resolved, high resolution spectra of the stellar radiation reflected by these objects, and the thermal radiation that they emit. Astronomical instrument simulator experiments will be used to assess the detectability of planetary characteristics in disk-averaged spectra.

The VPL will continue to synthesize expertise in observational and theoretical astronomy, Earth science, planetary science, chemistry, geology and biology to address key objectives in the Astrobiology Roadmap and the Universe Roadmap. Finally, the VPL is directly relevant to the NASA Vision for Space Exploration, as it directly informs and supports our charge to conduct advanced telescope searches for Earth-like planets and habitable environments around other stars.