Latitudinal Asymmetry in the Dayside Atmosphere of WASP-43b

DOI
Publisher DOI
Abstract
We present two-dimensional near-infrared temperature maps of the canonical hot Jupiter WASP-43b using a phase-curve observation with JWST NIRSpec/G395H. From the white-light planetary transit, we improve constraints on the planet's orbital parameters and measure a planet-to-star radius ratio of
. Using the white-light phase curve, we measure a longitude of maximum brightness of
east of the substellar point and a phase-curve offset of
. We also find a ≈4σ detection of a latitudinal hotspot offset of
, the first significant detection of a nonequatorial hotspot in an exoplanet atmosphere. We show that this detection is robust to variations within planetary parameter uncertainties, but only if the transit is used to improve constraints, showing the importance of transit observations to eclipse mapping. Maps retrieved from the NRS1 and NRS2 detectors are similar, with hotspot locations consistent between the two detectors at the 1σ level. Our JWST data show brighter (hotter) nightsides and a dimmer (colder) dayside at the shorter wavelengths relative to fits to Spitzer 3.6 and 4.5 μm phase curves. Through comparison between our phase curves and a set of general circulation models, we find evidence for clouds on the nightside and atmospheric drag or high metallicity reducing the eastward hotspot offset.
Date Issued
2024-07-01
Publication Type
Article
Language(s)
en
Author(s)
Challener, Ryan C.
Rustamkulov, Zafar
Lewis, Nikole
Sing, David K.
Birkmann, Stephan M.
Crouzet, Nicolas
Espinoza, Néstor
Manjavacas, Elena
Oliveros-Gomez, Natalia
Valenti, Jeff A.
Yang, Jingxuan
Additional Credits
Journal
The Astrophysical Journal Letters
Publisher
American Astronomical Society
ISSN
2041-8205
2041-8213
Access(Rights)
open.access
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