Endogenous CO2 ice mixture on the surface of Europa and no detection of plume activity

G L Villanueva; H B Hammel; S N Milam; S Faggi; V Kofman; L Roth; K P Hand; L Paganini; J Stansberry; J Spencer; S Protopapa; G Strazzulla; G Cruz-Mermy; C R Glein; R Cartwright; G Liuzzi

doi:10.1126/science.adg4270

Endogenous CO₂ ice mixture on the surface of Europa and no detection of plume activity

Science. 2023 Sep 22;381(6664):1305-1308. doi: 10.1126/science.adg4270. Epub 2023 Sep 21.

Authors

G L Villanueva¹, H B Hammel², S N Milam¹, S Faggi^{1

3}, V Kofman^{1

3}, L Roth⁴, K P Hand⁵, L Paganini⁶, J Stansberry⁷, J Spencer⁸, S Protopapa⁸, G Strazzulla⁹, G Cruz-Mermy¹⁰, C R Glein¹¹, R Cartwright¹², G Liuzzi¹³

Affiliations

¹ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
² Association of Universities for Research in Astronomy, Washington, DC 20004, USA.
³ American University, Washington, DC 20016, USA.
⁴ Royal Institute of Technology, Stockholm 104 50, Sweden.
⁵ Jet Propulsion Laboratory, Pasadena, CA 91109, USA.
⁶ NASA Headquarters, Washington, DC 20546, USA.
⁷ Space Telescope Science Institute, Baltimore, MD 21218, USA.
⁸ Southwest Research Institute, Boulder, CO 80302, USA.
⁹ Osservatorio Astrofisico di Catania, Istituto Nazionale di Astrofisica, 95123 Catania, Italy.
¹⁰ Universite Paris-Sarclay, 91190 Gif-sur-Yvette, France.
¹¹ Southwest Research Institute, San Antonio, TX 78238, USA.
¹² Carl Sagan Center for Research, Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA.
¹³ Università degli Studi della Basilicata, 85100 Potenza, Italy.

PMID: 37733858
DOI: 10.1126/science.adg4270

Abstract

Jupiter's moon Europa has a subsurface ocean beneath an icy crust. Conditions within the ocean are unknown, and it is unclear whether it is connected to the surface. We observed Europa with the James Webb Space Telescope (JWST) to search for active release of material by probing its surface and atmosphere. A search for plumes yielded no detection of water, carbon monoxide, methanol, ethane, or methane fluorescence emissions. Four spectral features of carbon dioxide (CO₂) ice were detected; their spectral shapes and distribution across Europa's surface indicate that the CO₂ is mixed with other compounds and concentrated in Tara Regio. The ¹³CO₂ absorption is consistent with an isotopic ratio of ¹²C/¹³C = 83 ± 19. We interpret these observations as indicating that carbon is sourced from within Europa.