Seventy-five billion m dwarfs in our galaxy host at least one small planet in the habitable zone (HZ). The stellar ultraviolet (UV) radiation from m dwarfs is strong and highly variable, and impacts…

This is a $3,185,938.39 grant awarded by the National Aeronautics and Space Administration (NASA) to Arizona State University (ASU), a U.S. state university, for the STAR-PLANET ACTIVITY RESEARCH CUBESAT (SPARCS) mission. The SPARCS mission will monitor 25 M-dwarf stars in the far-ultraviolet and near-ultraviolet spectrums from a 6U CubeSat platform. This data will be crucial for understanding the potential habitability of planets orbiting low-mass stars, which are the most common planet hosts. The grant will also support the training of undergraduate and graduate students as well as post-doctoral scholars. No set-aside designation was used for this award. This grant supports NASA's goal of identifying potentially habitable environments and will provide key context for interpreting future observations of potentially habitable exoplanets by the James Webb Space Telescope and future large telescopes.

Seventy-five billion m dwarfs in our galaxy host at least one small planet 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. These effects are amplified by the extreme proximity of their HZS (0.1 0.4 AU). Jwst will characterize HZ m dwarf planets and attempt the first spectroscopic search for life beyond the solar system. Knowing the UV environments of m dwarf planets will be crucial to understanding their atmospheric composition and a key parameter in discriminating between biological and abiotic sources for observed biosignatures. The UV flux emitted during the super-luminous premain sequence phase of m STARS drives water loss and photochemical O2 buildup for terrestrial planets within the HZ. This phase can persist for up to a billion years for the lowest mass m STARS. Afterwards, UV-driven photochemistry during the main sequence phase strongly affects a planet s atmosphere, could limit the planet s potential for habitability, and may confuse studies of habitability by creating false chemical biosignatures. Our proposed cubesat observatory will be the first mission to provide the time-dependent spectral slope, intensity and evolution of m dwarf stellar UV radiation. These measurements are crucial to interpreting observations of planetary atmospheres around low-mass STARS. Mission: the star-planet activity research cubesat (sparcs) will be a 6U cubesat devoted to monitoring 25 m STARS in two UV bands: sparcs far-UV (s- FUV: 153 171 NM) and sparcs near-UV (s-NUV: 260 300 NM). For each target, sparcs will observe continuously between one and three complete stellar rotations (4 45 days) over a mission lifetime of 2 years. A UV characterization survey of m dwarfs, the most common of planet hosts, is a perfect experiment for a cubesat: -- UV astronomy cannot be done from the ground because of earth s atmospheric absorption. -- photometry of nearby sources is an efficient use of a small aperture. -- unlike the HST, whose time is shared among many instruments and programs, a cubesat can provide dedicated space-based long-term monitoring in the UV. Technology: sparcs will advance UV detector technology by flying high quantum efficiency (QE), UV-optimized detectors developed at JPL. These delta-doped detectors have a long history of deployment demonstrating greater than 5X the sensitivity of the detectors used by galex. Sparcs will pave the way for their application in missions like luvoir or habex. Education: the sparcs research program will train future scientists and mission leaders by mentoring five undergraduate students, three graduate students, and two post-doctoral scholars throughout all aspects of the mission, including engineering, science, data management and outreach. Relevance to NASA: the sparcs mission will address NASA s goals of identifying the characteristics and distribution of potentially habitable environments, including HZ planet hosts like proxima and trappist-1. Sparcs will also be capable of targetof- opportunity UV observations of NASA s tess yield of rocky planets in m dwarf HZS, some of the first HZ planets to be spectroscopically characterized by jwst. Sparcs can provide the needed UV context for the interpretation of transmission and emission spectra of these potentially habitable planets. Further into the future, sparcs results will inform the target strategy for the enormous telescopic investments in exoplanet science of luvoir or habex. Sparcs technology will fill a GAP in NASA s capabilities to observe low-mass stellar/planetary systems in the FUV and NUV. HST s UV capabilities will not last much later than 2019, with future opportunities (e.g., luvoir) not arriving until sometime after 2035. The detector technology of this cubesat will play a crucial role in these and interim UV-capable missions.