Early Release Science of the Exoplanet WASP-39b with JWST NIRSpec G395H.

• DOI: 10.17863/cam.94225
• Publication Date: 2023-01-09
• Authors: Alderson, Lili; Wakeford, Hannah R.; Alam, Munazza K.; Batalha, Natasha E.; Lothringer, Joshu...; Adams Redai, Jeá I.; Barat, Saugata; Brande, Jonathan; Damiano, Mario; Daylan, Tansu; Espinoza, Néstor; Flagg, Laura S.; Goyal, Jayesh M.; Grant, David; Hu, Renyu; Inglis, Julie; Lee, Elspeth K.H.; Mikal-Evans, Thomas; Ramos-Rosado, Lak...; Roy, Pierre Alexis; Wallack, Nicole L.; Batalha, Natalie M.; Bean, Jacob L.; Benneke, Björn; Berta-Thompson, Z...; Carter, Aarynn L.; Changeat, Quentin; Colón, Knicole D.; Crossfield, Ian J.M.; Désert, Jean Michel; Foreman-Mackey, D...; Gibson, Neale P.; Kreidberg, Laura; Line, Michael R.; López-Morales, Me...; Molaverdikhani, K...; Moran, Sarah E.; Morello, Giuseppe; Moses, Julianne I.; Mukherjee, Sagnick; Schlawin, Everett A.; Sing, David K.; Stevenson, Kevin B.; Taylor, Jake; Aggarwal, Keshav; Ahrer, Eva Maria; Allen, Natalie H.; Barstow, Joanna K.; Bell, Taylor J.; Blecic, Jasmina; Casewell, Sarah L.; Chubb, Katy L.; Crouzet, Nicolas; Cubillos, Patrici...; Decin, Leen; Feinstein, Adina D.; Fortney, Joanthan J.; Harrington, Joseph; Heng, Kevin; Iro, Nicolas; Kempton, Eliza Mi...; Kirk, James; Knutson, Heather A.; Krick, Jessica E.; Leconte, Jérémy; Lendl, Monika A.; Macdonald, Ryan J.; Mancini, Luigi; Mansfield, Megan; May, Erin M.; Mayne, Nathan J.; Miguel, Yamila; Nikolov, Nikolay K.; Ohno, Kazumasa; Palle, Enric; Parmentier, Vivien; Petit Dit de la R...; Piaulet, Caroline; Powell, Diana K.; Rackham, Benjamin V.; Redfield, Seth L.; Rogers, Laura K.; Rustamkulov, Zafar; Tan, Xianyu; Tremblin, Pascal; Tsai, Shangmin; Turner, Jake D.; de Val-Borro, Miguel; Venot, Olivia; Welbanks, Luis; Wheatley, Peter J.; Zhang, Xi
• Keywords: 550; Extraterrestrial Environment; [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]; Planets; [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]; 5109 Space Sciences; 01 natural sciences; [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; QB Astronomy; 103004 Astrophysics; QC; QB; Earth and Planetary Astrophysics (astro-ph.EP); Multidisciplinary; Exoplanets; 520 Astronomy; article; 3rd-DAS; /639/33/34/862; 103004 Astrophysik; 520; Saturn; Astrophysics - Solar and Stellar Astrophysics; 5101 Astronomical Sciences; /639/33/34/2810; Astrophysics - Instrumentation and Methods for Astrophysics; 51 Physical Sciences; 530 Physics; FOS: Physical sciences; Settore FIS/05 - ASTRONOMIA E ASTROFISICA; Astronomical instrumentation; Article; /140; 0103 physical sciences; Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); MCC; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Atmosphere; 500; 500 Science; Oxygen; QC Physics; 13. Climate action; 627; Astrophysics - Earth and Planetary Astrophysics

AbstractMeasuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems1,2. Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based3–5 and high-resolution ground-based6–8 facilities. Here we report the medium-resolution (R ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref. 9), obtained with the Near Infrared Spectrograph (NIRSpec) G395H grating of JWST. Our observations achieve 1.46 times photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO2 (28.5σ) and H2O (21.5σ), and identify SO2 as the source of absorption at 4.1 μm (4.8σ). Best-fit atmospheric models range between 3 and 10 times solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO2, underscore the importance of characterizing the chemistry in exoplanet atmospheres and showcase NIRSpec G395H as an excellent mode for time-series observations over this critical wavelength range10.