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

Editor’s summaryEuropa, an icy moon of Jupiter, has a subsurface ocean beneath a crust of water ice. Solid carbon dioxide (CO2) has previously been observed on its surface, but the source was unknown. Two teams analyzed infrared spectroscopy of Europa from the James Webb Space Telescope to investigate the CO2 source. Trumbo and Brown found that the CO2 is concentrated in a region with geology that indicates transport of material to the surface from within the moon, and they discuss the implications for the composition of Europa’s internal ocean. Villanueva et al. also identified an internal origin of the CO2 and measured its 12C/13C isotope ratio. They searched for plumes of volatile material breaching the surface but found a lower activity than earlier observations. Together, these studies demonstrate that there is a source of carbon within Europa, probably in its ocean. —Keith T. Smith