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P7.1: Afrin Badhan, Mahmuda
Mahmuda Afrin Badhan (University of Maryland College Park)
Eric T. Wolf (University of Colorado Boulder)
Ravi Kumar Kopparapu (NASA Goddard Space Flight Center)
Eliza M.-R. Kempton (University of Maryland College Park)
Giada Arney (NASA Goddard Space Flight Center)
Shawn Domagal-Goldman (NASA Goddard Space Flight Center), Drake Deming (University of Maryland College Park)


Theme: Software for Solar Systems Astronomy
Title: STELLAR ACTIVITY EFFECTS ON MOIST HABITABLE TERRESTRIAL ATMOSPHERES AROUND M DWARFS

The first habitable zone (HZ) exoplanets to have their atmospheres characterized will likely be tidally-locked planets orbiting nearby M dwarfs. Future transit spectroscopy of such planets is part of the community’s plan in assessing their habitability. 3D climate modeling has shown tidally-locked HZ terrestrial planets, at the inner HZ of M dwarfs, may possess significantly enhanced water vapor content in the lower atmosphere compared to the 24 hour analog. For model M dwarfs with T 3000K in particular, such inner HZ planets have been shown to retain the moist atmosphere for low Earth-like instellation levels. This is promising for both habitability as well as our ability to spectrally detect this with the upcoming James Webb Space Telescope. However, while strong vertical mixing is expected to loft the water vapor high enough into the atmosphere, M dwarfs are typically high XUV environment. To assess whether the water vapor destruction continuously driven by such stellar UV activity levels would affect detectability, we run 1-D photochemical models of these atmospheres under varying stellar UV activity. To remain in the moist greenhouse regime as established in Kopparapu et al. 2017, we take the 3D model simulated abundances and temperature profiles for a N2-H2O dominated planet around a 3300K M dwarf. We also explore additional chemical complexity by introducing new species to our atmosphere. We find that as long as the atmosphere is well-mixed at 1 mbar and higher pressures, UV activity has no impact on our H2O detectability. We also find that even the highest UV scenario does not produce spectrally significant O3 for JWST.

Link to PDF (may not be available yet): P7-1.pdf