The new findings, presented in a pair of independent studies in the journal Science, provide fresh insights into the poorly known composition of the moon’s ocean beneath its crust of solid water ice.
The JWST’s observations have shown that carbon dioxide on Europa originates from within its icy body’s subsurface ocean.
Future missions planned to this moon would assess its potential habitability, depending on its chemistry, including the abundance of biologically essential elements like carbon.
While until now research has found the presence of solid carbon dioxide ice on Europa’s surface, it has remained unclear how the CO2 originated.
Researchers, including those from Cornell University in the US, have sought to determine whether the CO2 was delivered to the moon’s surface by meteorite impacts or if it was produced on the surface through interactions with Jupiter’s sphere of magnetic field around it.
They said determining the source of the CO2 would help draw constraints on the chemistry of Europa’s internal ocean.
In two new studies, scientists analysed data on infrared radiation of CO2 from Europa’s surface obtained using JWST.
One study mapped the distribution of CO2 on Europa and found its highest abundance is located in a nearly 1,800-square-kilometre region called Tara Regio. The region is dominated by “chaos terrain” or geologically disrupted resurfaced materials.
The amount of CO2 identified within this region – which has some of the youngest terrain on Europa’s surface – indicates it was derived from an internal source of carbon.
Based on this finding, scientists said this CO2 was formed within Europa’s subsurface ocean and brought to the surface on a geologically recent timescale.
This suggests the moon’s subsurface ocean contains carbon, one of the essential ingredients known for the formation of life.
The other study also found that the CO2 on Europa’s surface is sourced from within and mixed with other compounds.
While researchers could not distinguish whether this was a non-living or living source, the results in both studies complement each other and reinforce the conclusion that Europa’s subsurface ocean contains abundant carbon.