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Identification of carbon dioxide in an exoplanet atmosphere

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posted on 2024-01-24, 19:02 authored by Eva-Maria Ahrer, Lili Alderson, Natalie M Batalha, Natasha E Batalha, Jacob L Bean, Thomas G Beatty, Taylor J Bell, Bjorn Benneke, Zachory K Berta-Thompson, Aarynn L Carter, Ian JM Crossfield, Nestor Espinoza, Adina D Feinstein, Jonathan J Fortney, Neale P Gibson, Jayesh M Goyal, Eliza M-R Kempton, James Kirk, Laura Kreidberg, Mercedes Lopez-Morales, Michael R Line, Joshua D Lothringer, Sarah E Moran, Sagnick Mukherjee, Kazumasa Ohno, Vivien Parmentier, Caroline Piaulet, Zafar Rustamkulov, Everett Schlawin, David K Sing, Kevin B Stevenson, Hannah R Wakeford, Natalie H Allen, Stephan M Birkmann, Jonathan Brande, Nicolas Crouzet, Patricio E Cubillos, Mario Damiano, Jean-Michel Desert, Peter Gao, Joseph Harrington, Renyu Hu, Sarah Kendrew, Heather A Knutson, Pierre-Olivier Lagage, Jeremy Leconte, Monika Lendl, Ryan J MacDonald, EM May, Yamila Miguel, Karan Molaverdikhani, Julianne Moses, Catriona Anne Murray, Molly Nehring, Nikolay K Nikolov, DJM Petit Dit de la Roche, Michael Radica, Pierre-Alexis Roy, Keivan G Stassun, Jake Taylor, William C Waalkes, Patcharapol Wachiraphan, Luis Welbanks, Peter J Wheatley, Keshav Aggarwal, Munazza K Alam, Agnibha Banerjee, Joanna K Barstow, Jasmina Blecic, SL Casewell, Quentin Changeat, KL Chubb, Knicole D Colon, Louis-Philippe Coulombe, Tansu Daylan, Miguel De Val-Borro, Leen Decin, Leonardo A Dos Santos, Laura Flagg, Kevin France, Guangwei Fu, A Garcia Munoz, John E Gizis, Ana Glidden, David Grant, Kevin Heng, Thomas Henning, Yu-Cian Hong, Julie Inglis, Nicolas Iro, Tiffany Kataria, Thaddeus D Komacek, Jessica E Krick, Elspeth KH Lee, Nikole K Lewis, Jorge Lillo-Box, Jacob Lustig-Yaeger, Luigi Mancini, Avi M Mandell, Megan Mansfield, Mark S Marley, Thomas Mikal-Evans, Giuseppe Morello, Matthew C Nixon, Kevin Ortiz Ceballos, Anjali AA Piette, Diana Powell, Benjamin Rackham, Lakeisha Ramos-Rosado, Emily Rauscher, Seth Redfield, Laura K Rogers, Michael T Roman, Gael M Roudier, Nicholas Scarsdale, Evgenya L Shkolnik, John Southworth, Jessica J Spake, Maria E Steinrueck, Xianyu Tan, Johanna K Teske, Pascal Tremblin, Shang-Min Tsai, Gregory S Tucker, Jake D Turner, Jeff A Valenti, Olivia Venot, Ingo P Waldmann, Nicole L Wallack, Xi Zhang, Sebastian Zieba, JWST Transiting Exoplanet Community Early Release Science Team

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 (that is, elements heavier than helium, also called ‘metallicity’)1–3, and thus the formation processes of the primary atmospheres of hot gas giants4–6. It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets7–9. 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 owing to the lack of unambiguous spectroscopic identification10–12. 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 programme13,14. The data used in this study span 3.0–5.5 micrometres in wavelength and show a prominent CO2 absorption feature at 4.3 micrometres (26-sigma significance). The overall spectrum is well matched by one-dimensional, ten-times 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 micrometres that is not reproduced by these models.


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School of Physics & Astronomy, University of Leicester


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