Scientists using the ground-based IRAM radio telescope have observed a gas cloud around Saturn’s moon Enceladus from which they detected the signature of methanol, an organic molecule.
The discovery marks the first time any ground-based telescope has identified molecules from Enceladus.
According to Emily Drabek-Maunder of Cardiff University in Wales and fellow researchers based at Cardiff, Imperial College in London, and the Open University, the methanol is produced in the moon’s plumes in chemical reactions that occur after the plumes are ejected into space.
This means they are not produced by microbial life on Enceladus’ surface.
Scientists believe the plumes originate in Enceladus’ subsurface ocean, breaking through cracks in the moon’s icy surface before venting into space.
Methanol has been detected in the plumes by NASA’s Cassini spacecraft, which flew directly into them.
For this latest study, the research team used the 30-meter Institut de Radioastronomie Millimetrique (IRAM) radio telescope in Pico Veleta, Spain.
“This finding shows that detections of molecules at Enceladus are possible using ground-based facilities,” Drabek-Maunder said.
“However, to understand the complex chemistry in these subsurface oceans, we will need further direct observations by future spacecraft flying through Enceladus’ plumes.”
Material from Enceladus’ plumes travels as far as Saturn’s second outermost E ring.
Jane Greaves, also of Cardiff University, said the finding surprised the researchers, as methanol was not the primary molecule for which they were searching.
Members of the research team believe the methanol has two possible origins. One possibility is that it originated in a cloud of gas that came off Enceladus and subsequently became trapped in Saturn’s magnetic field.
The second theory is that a gas cloud ejected from Enceladus has spread into Saturn’s E ring.
A significantly larger amount of methanol has been detected in the cloud than was found by Cassini in the plumes.
Findings of the study were presented by the researchers at the UK National Astronomy meeting on July 3.