The search for signs of life in the atmospheres of terrestrial planets orbiting other stars is an exciting quest that is a key priority in both the Astro2020 and Planetary Science Decadal Surveys.  Terrestrial exoplanets, including those in a star’s habitable zone, are now being observed with the JWST space telescope to search for the presence of atmospheres. If found, these atmospheres will be studied to understand their composition and evolution, and the planet’s potential habitability.  These atmospheric observations will also enable the first searches for biosignatures, the impacts of life on a global planetary environment, such as gases released by metabolic processes. However, all biosignatures must be interpreted in the context of their planetary and stellar environment, to rule out planetary processes such as volcanism and photochemistry that may enhance, destroy or even mimic biosignatures.  In the near-term and due to observational considerations, our astrobiological studies will focus exclusively on the atmospheres of M dwarf exoplanets, which, due to the coevolution with their more active star, may undergo a very different evolutionary path to Earth’s.  In the longer term, the NASA flagship large-aperture space-based telescope, the Habitable Worlds Observatory, will use direct imaging techniques to obtain reflected light from planets orbiting a broader swath of host stars, to study their atmospheres and surfaces.  In this talk I will focus on  the work the VPL team are doing to understand terrestrial exoplanet evolution, habitability and biosignatures, and to predict what can be gleaned from observations of terrestrial exoplanets.  I will describe recent JWST results, and the potential capabilities for atmosphere and biosignature searches using JWST, and place these opportunities in the context of what might be possible with space-based telescopes in the next two decades.


Speaker: Dr. Victoria Meadows, UW-Astronomy, and UW Astrobiology Program Director
Host: Yasuhito Sekine, ELSI.


Date: Thu. 18 Apr. 16:00-17:00 JST


Venue: Mishima Hall, ELSI