Identification of carbon dioxide in an exoplanet atmosphere
Creators: name: The JWST Transiting Exoplanet Community Early Release Science Team
name: Ahrer, Eva-Maria
name: Alderson, Lili
name: Batalha, Natalie M.
name: Batalha, Natasha E.
name: Bean, Jacob L.
name: Beatty, Thomas G.
name: Bell, Taylor J.
name: Benneke, Björn
name: Berta-Thompson, Zachory K.
name: Carter, Aarynn L.
name: Crossfield, Ian J. M.
name: Espinoza, Néstor
name: Feinstein, Adina D.
name: Fortney, Jonathan J.
name: Gibson, Neale P.
name: Goyal, Jayesh M.
name: Kempton, Eliza M. -R.
name: Kirk, James
name: Kreidberg, Laura
name: López-Morales, Mercedes
name: Line, Michael R.
name: Lothringer, Joshua D.
name: Moran, Sarah E.
name: Mukherjee, Sagnick
name: Ohno, Kazumasa
name: Parmentier, Vivien
name: Piaulet, Caroline
name: Rustamkulov, Zafar
name: Schlawin, Everett
name: Sing, David K.
name: Stevenson, Kevin B.
name: Wakeford, Hannah R.
name: Allen, Natalie H.
name: Birkmann, Stephan M.
name: Brande, Jonathan
name: Crouzet, Nicolas
name: Cubillos, Patricio E.
name: Damiano, Mario
name: Désert, Jean-Michel
name: Gao, Peter
name: Harrington, Joseph
name: Hu, Renyu
name: Kendrew, Sarah
name: Knutson, Heather A.
name: Lagage, Pierre-Olivier
name: Leconte, Jérémy
name: Lendl, Monika
name: MacDonald, Ryan J.
name: May, E. M.
name: Miguel, Yamila
name: Molaverdikhani, Karan
name: Moses, Julianne I.
name: Murray, Catriona Anne
name: Nehring, Molly
name: Nikolov, Nikolay K.
name: de la Roche, D. J. M. Petit dit
name: Radica, Michael
name: Roy, Pierre-Alexis
name: Stassun, Keivan G.
name: Taylor, Jake
name: Waalkes, William C.
name: Wachiraphan, Patcharapol
name: Welbanks, Luis
name: Wheatley, Peter J.
name: Aggarwal, Keshav
name: Alam, Munazza K.
name: Banerjee, Agnibha
name: Barstow, Joanna K.
name: Blecic, Jasmina
name: Casewell, S. L.
name: Changeat, Quentin
name: Chubb, K. L.
name: Colón, Knicole D.
name: Coulombe, Louis-Philippe
name: Daylan, Tansu
name: de Val-Borro, Miguel
name: Decin, Leen
name: Santos, Leonardo A. Dos
name: Flagg, Laura
name: France, Kevin
name: Fu, Guangwei
name: Muñoz, A. García
name: Gizis, John E.
name: Glidden, Ana
name: Grant, David
name: Heng, Kevin
name: Henning, Thomas
name: Hong, Yu-Cian
name: Inglis, Julie
name: Iro, Nicolas
name: Kataria, Tiffany
name: Komacek, Thaddeus D.
name: Krick, Jessica E.
name: Lee, Elspeth K. H.
name: Lewis, Nikole K.
name: Lillo-Box, Jorge
name: Lustig-Yaeger, Jacob
name: Mancini, Luigi
name: Mandell, Avi M.
name: Mansfield, Megan
name: Marley, Mark S.
name: Mikal-Evans, Thomas
name: Morello, Giuseppe
name: Nixon, Matthew C.
name: Ceballos, Kevin Ortiz
name: Piette, Anjali A. A.
name: Powell, Diana
name: Rackham, Benjamin V.
name: Ramos-Rosado, Lakeisha
name: Rauscher, Emily
name: Redfield, Seth
name: Rogers, Laura K.
name: Roman, Michael T.
name: Roudier, Gael M.
name: Scarsdale, Nicholas
name: Shkolnik, Evgenya L.
name: Southworth, John
name: Spake, Jessica J.
name: Steinrueck, Maria E
name: Tan, Xianyu
name: Teske, Johanna K.
name: Tremblin, Pascal
name: Tsai, Shang-Min
name: Tucker, Gregory S.
name: Turner, Jake D.
name: Valenti, Jeff A.
name: Venot, Olivia
name: Waldmann, Ingo P.
name: Wallack, Nicole L.
name: Zhang, Xi
name: Zieba, Sebastian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Carbon dioxide (CO2) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO2 is an indicator of the metal enrichment (i.e., elements heavier than helium, also called "metallicity"), and thus formation processes of the primary atmospheres of hot gas giants. It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets. Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO2 but have not yielded definitive detections due to the lack of unambiguous spectroscopic identification. Here we present the detection of CO2 in the atmosphere of the gas giant exoplanet WASP-39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science Program (ERS). The data used in this study span 3.0 to 5.5 μm in wavelength and show a prominent CO2 absorption feature at 4.3 μm (26σ significance). The overall spectrum is well matched by one-dimensional, 10x solar metallicity models that assume radiative-convective-thermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide, and hydrogen sulfide in addition to CO2, but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0 μm that is not reproduced by these models.
description: 27 pages, 6 figures, Accepted for publication in Nature, data and models available at https://doi.10.5281/zenodo.6959427