Principal Investigator: Caroline Morley
PI Institution: University of Texas at Austin
Investigators
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Title: Can Dust in Outflows Obscure Exoplanet Transmission Spectra?
Cycle: 27
Abstract
Planets lose mass over the course of their lives, shaping the observed population. The Hubble Space Telescope has been our premier tool for observing this process in action over the past fifteen years, using UV spectroscopy targeting escaping hydrogen and, more recently, IR spectroscopy targeting escaping helium. We have now observed atmospheric escape from over half a dozen planets. HST has studied many of these planets extensively using transmission spectroscopy during transit, revealing that most of these planets, from hot Jupiters, to warm Neptunes, to low-gravity 'super puffs', have muted transmission spectra compared to cloud-free model atmospheres. Wang and Dai (2019) recently proposed that these two observations--atmospheric escape and muted spectra--could be intrinsically linked for very low-gravity planets, with dust entrained in outflows obscuring observed spectra. We propose to use theoretical simulations of mass loss, exospheric transmission spectra, and cloud/haze formation and destruction to investigate this proposed mechanism. We will apply these new models to a broad range of planets, including 3 hot Jupiters, 3 warm Neptunes, and 2 super puffs. Each planet we consider has an observed transmission spectrum with HST; the Jupiters and Neptunes have detected H or He exospheres; and the super puffs are expected to be in the process of losing their envelopes. Using these simulations, we seek to investigate whether this dusty outflow mechanism well above the hydrostatic atmosphere is obscuring our views of exoplanets during transit, muting their features. If so, this has broad implications for past and future exoplanet observations with HST and JWST.