Towering plume of water escaping from Saturn’s moon

Two Southwest Research Institute scientists were part of a James Webb Space Telescope (JWST) team that observed an imposing column of water vapor more than 6,000 miles long, about the distance between the US and Japan, spewed from the surface of Saturn’s moon Enceladus. In light of this NASA JWST Cycle 1 discovery, SwRI’s Dr. Christopher Glein also received a Cycle 2 assignment to study the plume, as well as key chemical compounds on the surface, to better understand potential habitability. of this ocean world.

During its 13-year reconnaissance of the Saturn system, the Cassini spacecraft discovered that Enceladus has an underground ocean of liquid water, and Cassini analyzed samples as plumes of ice grains and water vapor erupted into space from cracks in the surface. moon frost.

“Enceladus is one of the most dynamic objects in the solar system and is a prime target in humanity’s search for life beyond Earth,” said Glein, a leading expert in extraterrestrial oceanography. He is co-author of a paper recently accepted by Nature Astronomy. “In the years since NASA’s Cassini spacecraft first looked at Enceladus, we have never ceased to be amazed by what we find happening on this extraordinary moon.”

Once again, recent observations made with the Webb Near Infrared Spectrograph have yielded remarkable results.

“When I was looking at the data, at first, I thought I had to be wrong, it was so shocking to map a plume more than 20 times the diameter of the moon,” said Geronimo Villanueva of NASA’s Goddard Space Flight Center. and lead author of the recent article. “The plume extends much further than we could have imagined.”

Webb’s sensitivity reveals a new story about Enceladus and how it powers the water supply for the entire Saturn system and its rings. As Enceladus orbits the gas giant in just 33 hours, the moon spews water, leaving a halo, almost doughnut-like, in its wake. The plume is not only huge, but the water spans Saturn’s dense E ring. The JWST data indicates that about 30 percent of the water remains in the moon’s wake, while the other 70 percent escapes to supply the rest of the Saturn system.

“Webb’s observations, for the first time, visually illustrate how the moon’s water vapor plumes play a role in the formation of the torus,” said SwRI’s Dr. Silvia Protopapa, an expert in icy body composition analysis. in the sun. system that was also on the Cycle 1 team. “This serves as an impressive testament to Webb’s extraordinary abilities. I am delighted to be part of the Cycle 2 team as we begin our search for new indications of habitability and plume activity on Enceladus.” “.

Spurred on by the incredible findings of Webb’s first glimpse of Enceladus, Glein leads the same team that will observe Enceladus again with JWST next year.

“We will look for specific indicators of habitability, such as organic signatures and hydrogen peroxide,” Glein said. “Hydrogen peroxide is particularly interesting because it can provide much more powerful sources of metabolic energy than those we previously identified. Cassini did not give us a clear answer about the availability of such strong oxidants on Enceladus.”

The new observations will provide the best remote opportunity to search for indicators of surface habitability, by increasing the signal-to-noise ratio by up to a factor of 10 compared to Cycle 1. Understanding the temporal variability of plume outgassing is also important. to plan future planetary science missions targeting the plume.

“Webb can serve as a bridge between Cassini and the proposed search for life mission, Orbilander,” Glein said. “After Cycle 2, we’ll have a better idea if ocean samples are widely distributed over the surface of Enceladus, rather than just near the south pole. These upcoming observations could help us determine if Orbilander can access ocean samples near from the equator, which may help let’s go back to Enceladus first.

– This press release was originally published on the Southwest Research Institute website