NASA’s James Webb Space Telescope (JWST) has detected unusual jets of carbon monoxide and carbon dioxide from Centaur 29P, one of the most active icy bodies in the outer solar system. The findings offer new insights into the composition and evolution of centaurs, shedding light on the solar system’s formation.
JWST Detects Unusual Gas Jets from Centaur 29P, Revealing Clues to Solar System’s Early Formation
NASA’s James Webb Space Telescope (JWST) has made a remarkable discovery, detecting unusual gas jets emanating from Centaur 29P/Schwassmann-Wachmann 1 (29P), an active icy body located between Jupiter and Neptune. This centaur, known for its periodic outbursts, revealed never-before-seen jets of carbon monoxide (CO) and carbon dioxide (CO₂), offering valuable insights into the composition and evolution of these celestial bodies and their role in the formation of the solar system.
Centaur 29P and Its Unusual Behavior
Centaurs, named after the mythical half-human, half-horse creatures, are transitional objects between the Kuiper Belt and comets. They orbit between Jupiter and Neptune and are thought to be former trans-Neptunian objects that were moved closer to the Sun by the gravitational influences of the giant planets. Centaur 29P is particularly intriguing because it undergoes regular outbursts of gas and dust, making it one of the most active centaurs in the outer solar system. These outbursts occur every six to eight weeks.
Using JWST’s Near-Infrared Spectrograph (NIRSpec), scientists have now been able to map these jets in greater detail than ever before. Previous observations indicated that 29P emitted jets of carbon monoxide directed toward the Sun, but JWST's superior capabilities allowed researchers to observe jets of carbon dioxide, which had not been detected before.
As Sara Faggi, lead author of the study from NASA's Goddard Space Flight Center, noted, “Centaurs can be considered as some of the leftovers of our planetary system’s formation. Because they are stored at very cold temperatures, they preserve information about volatiles in the early stages of the solar system.” She added, “Webb really opened the door to a resolution and sensitivity that was impressive to us—when we saw the data for the first time, we were excited. We had never seen anything like this.”
Mapping the Jets and Uncovering 29P's Composition
The study revealed two CO₂ jets emanating from north and south regions of 29P’s nucleus and a CO jet pointing towards the north. The discovery of CO₂ is significant, as it is one of the main ways carbon is stored in the solar system. This finding suggests that the surface of Centaur 29P is more complex than previously thought.
Analyzing the data, the team also created a 3D model of the jets to better understand their orientation and origin. They concluded that the jets likely came from different regions on the centaur’s surface, which may suggest that the nucleus is composed of distinct bodies with varied compositions. Geronimo Villanueva, co-author of the study, said, “The fact that Centaur 29P has such dramatic differences in the abundance of CO and CO₂ across its surface suggests that 29P may be made of several pieces. Maybe two pieces coalesced together and made this centaur, which is a mixture between very different bodies that underwent separate formation pathways.”
The Ongoing Mystery of Outbursts
While JWST’s observations have provided significant insights, several mysteries about Centaur 29P remain. The exact mechanisms driving its regular outbursts are still unknown. Unlike comets, where water sublimation drives the jets, 29P is too far from the Sun for water ice to sublimate. Instead, the jets are likely driven by the release of other volatile gases, such as CO and CO₂.
As Adam McKay, another co-author of the study, explained, “We only had time to look at this object once, like a snapshot in time. I’d like to go back and look at Centaur 29P over a much longer period of time. Do the jets always have that orientation? Is there perhaps another carbon monoxide jet that turns on at a different point in the rotation period?” These questions will require further observations to answer, but JWST’s unprecedented sensitivity has already paved the way for deeper exploration of these enigmatic objects.