Blast from the Past: Ultraviolet Investigations of Exoplanet Systems and their Habitability

Thursday, November 7, 2019 - 4:00pm
Phillips Auditorium

Roughly seventy-five billion low-mass stars (a.k.a. M dwarfs) in our galaxy host one or more small planets in the habitable zone (HZ). The stellar ultraviolet (UV) radiation from M dwarfs is strong and highly variable, and impacts planetary atmospheric loss, composition and habitability. In fact, superflares occur daily in their first ~100 Myr, and these effects are amplified by the extreme proximity of their HZs. Understanding the UV environments of M dwarf planets is crucial to understanding atmospheric composition and evolution, and providing context for measured exoplanet spectra. For HZ terrestrial planets, characterization of the UV provides a key parameter in a planet’s potential for habitability as well as for discriminating between biological and abiotic sources of observed biosignatures. Our efforts to study the stellar UV span past, present and future space telescopes: the Galaxy Evolution Explorer (GALEX), the Hubble Space Telescope (HST), and the upcoming NASA-funded Star-Planet Activity Research CubeSat (SPARCS), due for launch at the end of 2021. SPARCS will be a 6U CubeSat completely devoted to continuous photometric monitoring of M stars, measuring their variability, flare rates and evolution, while also being a pathfinder for much-needed future UV missions.

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