Exoplanets on highly eccentric orbits offer unique insights into how planetary atmospheres respond to extreme variations in stellar forcing. By measuring the reradiation of heat near the planet's closest approach to its host star (periapse passage), we can obtain a direct measure of the radiative timescales that remain ambiguous for planets on circular orbits. We propose to observe with HST/WFC3 a partial-orbit spectroscopic phase curve of the highly-eccentric transiting exoplanet, HAT-P-2b. These observations, which build on our recent, successful demonstration of HST phase curve observations, will start before transit, continue through periapse passage, and end after secondary eclipse. The wavelength range offered by the WFC3 instrument probes deeper, previously-uncharted atmospheric pressure levels where dynamical processes become relevant in shaping the observed spatial and temporal flux variations. Phase curve observations through periapse passage are the key to constraining the timescales of planetary response. Our investigation will disentangle the contributions of radiative, dynamical, and chemical processes at work in strongly irradiated atmospheres, enabling it to become a model for the broader class of hot Jupiters.
|Effective start/end date||12/1/20 → 11/30/23|
- National Aeronautics Space Administration (NASA): $14,979.00