Using the James Webb Space Telescope (JWST), researchers have successfully detected water from a main belt comet for the first time in 15 years of testing. Recently published article Nature “Direct detection of water Main belt comets with JWST, led by Michael Kelly of the University of Maryland, have reported the first direct spectroscopic detection of water emission from a main belt comet called Comet Read. Henry Hsieh, Senior Research Fellow at the Planetary Science Institute, is a co-author of the paper.

Main belt comets are a rare subclass of comets known to astronomers that have mostly circular orbits, completely confined to the main asteroid belt between the orbits of Mars and Jupiter, but exhibit comet behavior – forming a fuzzy appearance and often ejecting tail-forming material. I believe it was formed by the sublimation of icy material – or by the direct transition of ice to gas.

However, despite numerous attempts to detect the main gases that should also accompany subconscious comet activity, only dust ejected by main belt comets has so far been detected. Most main belt asteroids are not expected to have much ice, given their location in the warm inner Solar System, where they are thought to have lived for billions of years.

By comparison, most other comets that exhibit sublimation-induced activity spend most of their time in the cold outer Solar System in rather long orbits that pass through the inner Solar System only occasionally. Given these considerations, doubts remain as to whether main belt comets will actually be icy. Now.

“Since the discovery of main belt comets, we have collected a substantial amount of evidence that their activity is due to sublimation, but so far it has all been indirect. This new JWST result is based on a main belt comet, as studies in 2008 aimed to detect gaseous eruption in main belt comets using some of the world’s ejection of water from its star, or the first direct evidence of sublimation in any form of ejection from the largest ground-based telescopes.”

In the paper, Xie and colleagues also showed that Comet Reed, and thus possibly other main-belt comets, has a fundamentally different chemical composition from other comets, and that carbon dioxide, a common component of gas efflux from the comet, is nearly absent. to comets. amount of water available. Whether it has experienced different formation conditions or evolutionary history,

Comet Reed is not a recent attack from the outer Solar System to the asteroid belt. Based on these results, main belt comets represent a sample of volatile material not currently represented in classical comet observations and meteorite records, making them important for understanding the volatile supply and subsequent evolution of the early Solar System.

“There has always been a significant amount of water ice, a key component of volatile material that normally drives activity in ‘classical’ outer Solar System comets, as it is unexpected for main belt asteroids given how close they are to the Sun. “It doubts whether the comet activity is due to the sublimation of water ice, rather than some other ice-free process, such as collisions or material ejected into space by fast-spinning asteroids.”

“Water in main belt comets is important because objects in the asteroid main belt have been proposed as a potential source of terrestrial water in the early solar system, where modern main belt comets provide an opportunity to test this hypothesis. But this only works if they actually contain water ice. Xie said. “Confirmation of water release in at least one main belt comet confirms that learning the source of water on Earth from main belt comets is a viable possibility,” he said.

The team used JWST to observe Reed shortly after its closest approach to the Sun, when outgassing is expected to be strongest, and used both imaging and near-infrared spectroscopic observations to look for the distinctive spectroscopic properties of water vapor and other common sublimation gases. performed.