While the main asteroid belt is primarily home to rocky bodies, it occasionally hosts comet-like bodies like Comet 238P/Read.
Through the keen “eyes” of the James Webb Space Telescope, researchers probing Comet 238P/Read, located in the heart of the main asteroid belt, have made a momentous finding. The identification of water vapor in this comet bolsters theories suggesting that comets might have transported life-sustaining water on Earth from the cosmos.
James Webb, a Cosmic Mystery: The Missing Carbon Dioxide
In a twist, the study also revealed a mystery: the expected carbon dioxide was absent from Comet 238P/Read. This surprising finding puzzled the team, given previous estimates that comets could contain up to 10% carbon dioxide in their volatile matter, which the sun easily evaporates.
Deciphering the Absence of Carbon Dioxide in Comet 238P/Read
Two possible explanations exist for Comet 238P/Read’s missing carbon dioxide. The comet may have lost its carbon dioxide due to solar warming over time, or it might have formed in a region of the solar system lacking the compound. “Being in the asteroid belt for a long time could do it — carbon dioxide vaporizes more easily than water ice and could percolate out over billions of years,” commented astronomer Michael Kelley.
Comets in the Main Asteroid Belt
While the main asteroid belt is primarily home to rocky bodies, it occasionally hosts comet-like bodies like Comet 238P/Read. These bodies periodically brighten due to a surrounding halo of material or a coma and can develop a comet-like tail.
James Webb: Unlocking the Secrets of Main Belt Comets like Comet 238P/Read
The “main belt comet” classification is relatively new, with Comet 238P/Read being instrumental in establishing this family of comets. This discovery provides the first conclusive evidence that these icy bodies, too, can retain frozen water.
The First Detailed Observation of a Main-Belt Comet
The Webb telescope’s detailed observation marks the first time gas has been confirmed in a main-belt comet. “Understanding the history of water distribution in the solar system will help us understand other planetary systems and if they could be on their way to hosting an Earth-like planet,” said research co-author Stefanie Milam.
The Next Steps in Comet Study
The team now aims to study more comets like Comet 238P/Read to determine if they have similar compositions. Co-author Heidi Hammel enthused, “Do other main belt comets also lack carbon dioxide? Either way, it will be exciting to find out.”
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