Ahrer, Eva-Maria;
Stevenson, Kevin B;
Mansfield, Megan;
Moran, Sarah E;
Brande, Jonathan;
Morello, Giuseppe;
Murray, Catriona A;
... Zhang, Xi; + view all
(2023)
Early Release Science of the exoplanet WASP-39b with JWST NIRCam.
Nature
, 614
pp. 653-658.
10.1038/s41586-022-05590-4.
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Abstract
Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining the dominant chemical processes at work and, if in equilibrium, revealing planet formation histories. Transmission spectroscopye.g., 1,2 provides the necessary means by constraining the abundances of oxygen- and carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution, and high precision that, together, are not achievable with previous observatories. Now that JWST has commenced science operations, we are able to observe exoplanets at previously uncharted wavelengths and spectral resolutions. Here we report time-series observations of the transiting exoplanet WASP-39b using JWST's Near InfraRed Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength photometric light curves span 2.0 - 4.0 µm, exhibit minimal systematics, and reveal well-defined molecular absorption features in the planet's spectrum. Specifically, we detect gaseous H2O in the atmosphere and place an upper limit on the abundance of CH4. The otherwise prominent CO2 feature at 2.8 µm is largely masked by H2O. The best-fit chemical equilibrium models favour an atmospheric metallicity of 1-100× solar (i.e., an enrichment of elements heavier than helium relative to the Sun) and a sub-stellar carbon-to-oxygen (C/O) ratio. The inferred high metallicity and low C/O ratio may indicate significant accretion of solid materials during planet formatione.g., 3,4 or disequilibrium processes in the upper atmospheree.g., 5,6.
| Type: | Article |
|---|---|
| Title: | Early Release Science of the exoplanet WASP-39b with JWST NIRCam |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41586-022-05590-4 |
| Publisher version: | https://doi.org/10.1038/s41586-022-05590-4 |
| Language: | English |
| Additional information: | © 2023 Springer Nature Limited. This article is licensed under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10163396 |
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