A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve.

Autor: Kempton EM; Department of Astronomy, University of Maryland, College Park, MD, USA. ekempton@astro.umd.edu., Zhang M; Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA., Bean JL; Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA., Steinrueck ME; Max-Planck Institute for Astronomy, Heidelberg, Germany., Piette AAA; Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA., Parmentier V; Department of Physics, University of Oxford, Oxford, UK.; Lagrange Laboratory, University of the Côte d'Azur, Observatory of the Côte d'Azur, CNRS, Nice, France., Malsky I; Department of Astronomy, University of Michigan, Ann Arbor, MI, USA., Roman MT; School of Physics and Astronomy, University of Leicester, Leicester, UK., Rauscher E; Department of Astronomy, University of Michigan, Ann Arbor, MI, USA., Gao P; Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA., Bell TJ; BAER Institute, NASA Ames Research Center, Moffet Field, CA, USA., Xue Q; Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA., Taylor J; Department of Physics, University of Oxford, Oxford, UK.; Institut Trottier de Recherche sur les Exoplanètes and Department of Physics, University of Montréal, Montréal, Quebec, Canada., Savel AB; Department of Astronomy, University of Maryland, College Park, MD, USA.; Center for Computational Astrophysics, Flatiron Institute, New York, NY, USA., Arnold KE; Department of Astronomy, University of Maryland, College Park, MD, USA., Nixon MC; Department of Astronomy, University of Maryland, College Park, MD, USA., Stevenson KB; Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA., Mansfield M; Steward Observatory, University of Arizona, Tucson, AZ, USA., Kendrew S; European Space Agency, Space Telescope Science Institute, Baltimore, MD, USA., Zieba S; Max-Planck Institute for Astronomy, Heidelberg, Germany.; Leiden Observatory, Leiden University, Leiden, the Netherlands., Ducrot E; Paris Region Fellow, Marie Sklodowska-Curie Action, Paris, France.; AIM, CEA, CNRS, University of Paris-Saclay, University of Paris, Gif-sur-Yvette, France., Dyrek A; AIM, CEA, CNRS, University of Paris-Saclay, University of Paris, Gif-sur-Yvette, France., Lagage PO; AIM, CEA, CNRS, University of Paris-Saclay, University of Paris, Gif-sur-Yvette, France., Stassun KG; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA., Henry GW; Center of Excellence in Information Systems, Tennessee State University, Nashville, TN, USA., Barman T; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA., Lupu R; Eureka Scientific, Inc., Oakland, CA, USA., Malik M; Department of Astronomy, University of Maryland, College Park, MD, USA., Kataria T; NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA., Ih J; Department of Astronomy, University of Maryland, College Park, MD, USA., Fu G; Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA., Welbanks L; School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA., McGill P; Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA, USA.
Jazyk: angličtina
Zdroj: Nature [Nature] 2023 Aug; Vol. 620 (7972), pp. 67-71. Date of Electronic Publication: 2023 May 10.
DOI: 10.1038/s41586-023-06159-5
Abstrakt: 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 1 . Population statistics show that close-in planets in this size range bifurcate into two classes on the basis of their radii 2,3 . 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 4 . GJ 1214b is an archetype sub-Neptune that has been observed extensively using transmission spectroscopy to test this hypothesis 5-14 . 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 H 2 O 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.
(© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)
Databáze: MEDLINE
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