A spatial map of the atmospheric limb of a hot Jupiter

Abstract Planets are inherently three-dimensional objects shaped by their thermal structure and dynamics. Observations of transiting exoplanets have begun to uncover this three-dimensional nature, with JWST measuring their dayside atmosphere structure with eclipse mapping and exploring spectroscopic asymmetries in the limbs of planets during transit. Here we apply the novel transmission strings mapping method to the hot Jupiter WASP-17 b. With this method, we are not only able to extract hemispheric limb asymmetries from east-to-west, but can also map equator-to-pole variations around the transmitting atmosphere as a function of angle, spanning 0.6–12 μm. We find a clear transition in the thermal scale height around the limb of the atmosphere, with an approximately 650 K temperature difference between the morning ( $$85{8}_{-233}^{+434}\,{\mathrm{K}}$$ 85 8 − 233 + 434 K ) and evening $$1{,}52{2}_{-114}^{+116}\,{\mathrm{K}}$$ 1 , 52 2 − 114 + 116 K ). These results are consistent with both nightside emission and dayside eclipse mapping measurements, and represent a fully comprehensive set of observations for a transiting exoplanet. We are also able to constrain the abundances of H 2 O and CO 2 to constant values around the limb, providing observational constraints for results from global circulation models. The transmission string technique, combined with the outstanding observability of WASP-17 b, pushes the study of exoplanet atmospheres further into a three-dimensional understanding of hot Jupiter dynamics and chemistry.

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Publication Details

Journal
Nature Astronomy
Published
2026-10-14
DOI
https://doi.org/10.1038/s41550-026-02986-4
Citations
1
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
3.12

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article

A spatial map of the atmospheric limb of a hot Jupiter

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1 citations
Nature Astronomy
Stellar, planetary, and galactic studies
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article

A spatial map of the atmospheric limb of a hot Jupiter

David Grant, Jeff A. Valenti, Roeland P. van der Marel, Jayesh Goyal, Dana R. Louie, Mark Hammond, Amélie Gressier, Jingcheng Huang, Maura Lally, Nikole K. Lewis, Natalie H. Allen, Elijah Mullens, Jacob Lustig‐Yaeger, Cathal Maguire, Daniel T. Valentine, Tiffany Kataria, Lili Alderson, Kristin S. Sotzen, Hannah R. Wakeford, Ana Glidden, Avinash Verma
article en
1 citations

Abstract

Abstract Planets are inherently three-dimensional objects shaped by their thermal structure and dynamics. Observations of transiting exoplanets have begun to uncover this three-dimensional nature, with JWST measuring their dayside atmosphere structure with eclipse mapping and exploring spectroscopic asymmetries in the limbs of planets during transit. Here we apply the novel transmission strings mapping method to the hot Jupiter WASP-17 b. With this method, we are not only able to extract hemispheric limb asymmetries from east-to-west, but can also map equator-to-pole variations around the transmitting atmosphere as a function of angle, spanning 0.6–12 μm. We find a clear transition in the thermal scale height around the limb of the atmosphere, with an approximately 650 K temperature difference between the morning ( $$85{8}_{-233}^{+434}\,{\mathrm{K}}$$ 85 8 − 233 + 434 K ) and evening $$1{,}52{2}_{-114}^{+116}\,{\mathrm{K}}$$ 1 , 52 2 − 114 + 116 K ). These results are consistent with both nightside emission and dayside eclipse mapping measurements, and represent a fully comprehensive set of observations for a transiting exoplanet. We are also able to constrain the abundances of H 2 O and CO 2 to constant values around the limb, providing observational constraints for results from global circulation models. The transmission string technique, combined with the outstanding observability of WASP-17 b, pushes the study of exoplanet atmospheres further into a three-dimensional understanding of hot Jupiter dynamics and chemistry.

Nature Astronomy
Space Telescope Science Institute (US), Goddard Space Flight Center (US), Jet Propulsion Laboratory (US), Johns Hopkins University (US), National Institute of Science Education and Research (IN), Cornell University (US), Johns Hopkins University Applied Physics Laboratory (US), University of Bristol (GB), University of Oxford (GB), Montreal Clinical Research Institute (CA), Massachusetts Institute of Technology (US), Catholic University of America (US)
National Aeronautics and Space Administration, Space Telescope Science Institute, Government of the United Kingdom, UK Research and Innovation, HORIZON EUROPE Framework Programme, Engineering and Physical Sciences Research Council, Science and Technology Facilities Council
Openalex Percentile: Top 6%
Stellar, planetary, and galactic studies
3.12
DOIOpen Access PDFOpenAlex
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