A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve
Author
Kempton, Eliza M.-R.Zhang, Michael

Bean, Jacob L.

Steinrueck, Maria E.
Piette, Anjali A. A.
Parmentier, Vivien
Malsky, Isaac
Roman, Michael T.
Rauscher, Emily
Gao, Peter
Bell, Taylor J.

Xue, Qiao
Taylor, Jake
Savel, Arjun B.
Arnold, Kenneth E.
Nixon, Matthew C.
Stevenson, Kevin B.
Mansfield, Megan
Kendrew, Sarah
Zieba, Sebastian
Ducrot, Elsa
Dyrek, Achrène
Lagage, Pierre-Olivier
Stassun, Keivan G.

Henry, Gregory W.
Barman, Travis
Lupu, Roxana
Malik, Matej
Kataria, Tiffany
Ih, Jegug
Fu, Guangwei
Welbanks, Luis
McGill, Peter
Affiliation
Lunar and Planetary Laboratory, University of ArizonaSteward Observatory, University of Arizona
Issue Date
2023-05-10
Metadata
Show full item recordPublisher
Springer Science and Business Media LLCCitation
Kempton, E.MR., Zhang, M., Bean, J.L. et al. A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve. Nature 620, 67–71 (2023). https://doi.org/10.1038/s41586-023-06159-5Journal
NatureRights
© The Author(s), under exclusive licence to Springer Nature Limited 2023.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
There are no planets intermediate in size between Earth and Neptune in our Solar System, yet these objects are found around a substantial fraction of other stars. Population statistics show that close-in planets in this size range bifurcate into two classes on the basis of their radii. It is proposed that the group with larger radii (referred to as `sub-Neptunes') is distinguished by having hydrogen-dominated atmospheres that are a few percent of the total mass of the planets. GJ 1214b is an archetype sub-Neptune that has been observed extensively using transmission spectroscopy to test this hypothesis. However, the measured spectra are featureless, and thus inconclusive, due to the presence of high-altitude aerosols in the planet's atmosphere. Here we report a spectroscopic thermal phase curve of GJ 1214b obtained with the James Webb Space Telescope (JWST) in the mid-infrared. The dayside and nightside spectra (average brightness temperatures of 553 ± 9 and 437 ± 19 K, respectively) each show more than 3σ evidence of absorption features, with H2O as the most likely cause in both. The measured global thermal emission implies that GJ 1214b's Bond albedo is 0.51 ± 0.06. Comparison between the spectroscopic phase curve data and three-dimensional models of GJ 1214b reveal a planet with a high metallicity atmosphere blanketed by a thick and highly reflective layer of clouds or haze.Note
6 month embargo; first published 10 May 2023ISSN
0028-0836EISSN
1476-4687PubMed ID
37164036Version
Final accepted manuscriptae974a485f413a2113503eed53cd6c53
10.1038/s41586-023-06159-5
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