In:
The Astronomical Journal, American Astronomical Society, Vol. 163, No. 1 ( 2022-01-01), p. 7-
Abstract:
Here we present a thermal emission spectrum of WASP-79b, obtained via Hubble Space Telescope Wide Field Camera 3 G141 observations as part of the PanCET program. As we did not observe the ingress or egress of WASP-79b’s secondary eclipse, we consider two scenarios: a fixed mid-eclipse time based on the expected occurrence time, and a mid-eclipse time as a free parameter. In both scenarios, we can measure thermal emission from WASP-79b from 1.1 to 1.7 μ m at 2.4 σ confidence consistent with a 1900 K brightness temperature for the planet. We combine our observations with Spitzer dayside photometry (3.6 and 4.5 μ m) and compare these observations to a grid of atmospheric forward models that span a range of metallicities, carbon-to-oxygen ratios, and recirculation factors. Given the strength of the planetary emission and the precision of our measurements, we found a wide range of forward models to be consistent with our data. The best-match equilibrium model suggests that WASP-79b’s dayside has a solar metallicity and carbon-to-oxygen ratio, alongside a recirculation factor of 0.75. Models including significant H − opacity provide the best match to WASP-79b’s emission spectrum near 1.58 μ m. However, models featuring high-temperature cloud species—formed via vigorous vertical mixing and low sedimentation efficiencies—with little day-to-night energy transport also match WASP-79b’s emission spectrum. Given the broad range of equilibrium chemistry, disequilibrium chemistry, and cloudy atmospheric models consistent with our observations of WASP-79b’s dayside emission, further observations will be necessary to constrain WASP-79b’s dayside atmospheric properties.
Type of Medium:
Online Resource
ISSN:
0004-6256
,
1538-3881
DOI:
10.3847/1538-3881/ac2f4a
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2022
detail.hit.zdb_id:
2207625-6
detail.hit.zdb_id:
2003104-X
SSG:
16,12
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