JWST-TST DREAMS: Nonuniform Dayside Emission for WASP-17b from MIRI/LRS

Abstract We present the first spectroscopic characterization of the dayside atmosphere of WASP-17b in the mid-infrared using a single JWST MIRI/LRS eclipse observation. From forward-model fits to the 5–12 μ m emission spectrum, we tightly constrain the heat redistribution factor of WASP-17b to be 0.92 ± 0.02 at the pressures probed by this data, indicative of inefficient global heat redistribution. We also marginally detect a supersolar abundance of water, consistent with previous findings for WASP-17b, but note our weak constraints on this parameter. These results reflect the thermodynamically rich but chemically poor information content of MIRI/LRS emission data for high-temperature hot Jupiters. Using the eclipse mapping method, which utilizes the signals that the spatial emission profile of an exoplanet imprints on the eclipse light curve during ingress/egress due to its partial occultation by the host star, we also construct the first eclipse map of WASP-17b, allowing us to diagnose its multidimensional atmospheric dynamics for the first time. We find a day–night temperature contrast of order 1000 K at the pressures probed by this data, consistent with our derived heat redistribution factor, along with an eastward longitudinal hotspot offset of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>18.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>11.1</mml:mn> <mml:mo>◦</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> , indicative of the presence of an equatorial jet induced by day–night thermal forcing being the dominant redistributor of heat from the substellar point. These dynamics are consistent with general circulation model predictions for WASP-17b. This work is part of a series of studies by the JWST Telescope Scientist Team, in which we use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy.

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Publication Details

Journal
The Astronomical Journal
Published
2024-08-21
DOI
https://doi.org/10.3847/1538-3881/ad5c61
Citations
10
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
3.32

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article

JWST-TST DREAMS: Nonuniform Dayside Emission for WASP-17b from MIRI/LRS

Natasha E. Batalha, David Grant, Jeff A. Valenti, Roeland P. van der Marel et al.
10 citations
The Astronomical Journal
Stellar, planetary, and galactic studies
3.32
article

JWST-TST DREAMS: Nonuniform Dayside Emission for WASP-17b from MIRI/LRS

Natasha E. Batalha, David Grant, Jeff A. Valenti, Roeland P. van der Marel, Jayesh Goyal, Dana R. Louie, Amélie Gressier, Jingcheng Huang, Erin May, Kevin B. Stevenson, Nikole K. Lewis, Natalie H. Allen, Elijah Mullens, Sara Seager, Marshall D. Perrin, Ryan J. MacDonald, Néstor Espinoza, Ryan C. Challener, Zifan Lin, Daniel T. Valentine, Lili Alderson, Douglas Long, C. M. Mountain, Hannah R. Wakeford, Mark Clampin, Ana Glidden
article en
10 citations

Abstract

Abstract We present the first spectroscopic characterization of the dayside atmosphere of WASP-17b in the mid-infrared using a single JWST MIRI/LRS eclipse observation. From forward-model fits to the 5–12 μ m emission spectrum, we tightly constrain the heat redistribution factor of WASP-17b to be 0.92 ± 0.02 at the pressures probed by this data, indicative of inefficient global heat redistribution. We also marginally detect a supersolar abundance of water, consistent with previous findings for WASP-17b, but note our weak constraints on this parameter. These results reflect the thermodynamically rich but chemically poor information content of MIRI/LRS emission data for high-temperature hot Jupiters. Using the eclipse mapping method, which utilizes the signals that the spatial emission profile of an exoplanet imprints on the eclipse light curve during ingress/egress due to its partial occultation by the host star, we also construct the first eclipse map of WASP-17b, allowing us to diagnose its multidimensional atmospheric dynamics for the first time. We find a day–night temperature contrast of order 1000 K at the pressures probed by this data, consistent with our derived heat redistribution factor, along with an eastward longitudinal hotspot offset of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>18.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>11.1</mml:mn> <mml:mo>◦</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> , indicative of the presence of an equatorial jet induced by day–night thermal forcing being the dominant redistributor of heat from the substellar point. These dynamics are consistent with general circulation model predictions for WASP-17b. This work is part of a series of studies by the JWST Telescope Scientist Team, in which we use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy.

The Astronomical JournalVol. 168(3)
Ames Research Center (US), Space Telescope Science Institute (US), Goddard Space Flight Center (US), Association of Universities for Research in Astronomy (US), Johns Hopkins University (US), National Institute of Science Education and Research (IN), University of America (US), Cornell University (US), University of Michigan (US), Johns Hopkins University Applied Physics Laboratory (US), University of Bristol (GB), Université Bourgogne Franche-Comté (FR), American Institute of Aeronautics and Astronautics (US), 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, University of Bristol, Nuclear Safety and Security Commission, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Eurostars
Openalex Percentile: Top 8%
Stellar, planetary, and galactic studies
3.32
DOIOpen Access PDFOpenAlex
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