The James Webb Space Telescope has detected water around a rare comet located in the main asteroid belt between Jupiter and Mars.
The observation represents another scientific breakthrough for the James Webb Space Telescope (JWST), marking the first time gas, in this case water vapor, has been detected around a comet in the main asteroid belt. This is important because it shows that water in the early solar system could have been preserved as ice in the main asteroid belt.
“In the past, we’ve seen main belt objects with all the characteristics of comets, but only with the right spectroscopic data from JWST are we able to say ‘yes,’ it must be water ice creating this effect,” said University of Maryland astronomer Michael Kelly. who led this research, in a statement (Opens in a new tab). “Through JWST’s observations of Comet Read, we can now show that water ice from the early solar system could be maintained in the asteroid belt.”
The discovery of water vapor around comet 238P/Read could significantly strengthen the theory that water, a vital element for life, was delivered to our planet from space via comets. But studying comets also presents a conundrum: carbon dioxide, which astronomers are expected to see, is missing from comet 238P/Reed.
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The lack of carbon dioxide around comet 238P/Read surprised the team more than the discovery of water vapor, because this compound was previously calculated to make up up to 10% of the volatile matter in a volatile comet. by the sun.
The team says there are two possible reasons behind Comet 238P/Read’s loss of carbon dioxide. First, comets may contain carbon dioxide during their formation, which is lost due to the heating of the Sun.
“Being in the asteroid belt for a long time can do just that – carbon dioxide is more volatile than water ice and can seep out over billions of years,” Kelly said.
An alternative theory for the carbon dioxide deficiency is that this main comet belt may have formed in a region of the solar system without it.
“Come here often?” Investigating main asteroid belt comets?
As the name suggests, the main asteroid belt is home to rocky bodies such as asteroids. However, it also hosts the occasional comet-like object such as Comet 238P/Read. These cometary objects can be identified by the fact that they periodically glow as a halo of matter, or coma, that surrounds them. They may also develop a tail of matter that is characteristic of comets.
The coma and tail of the comet originate from solid ice material, which immediately turns into gas through a process called sublimation when the comet approaches the Sun and heats up. It is this sublimation that causes astronomers to ascribe all comets to the Kuiper Belt far beyond Neptune, or the Oort Cloud, which is believed to be at the edge of the solar system. Both locations of water ice on these bodies would provide protection from solar radiation, allowing them to be conserved, while locations closer to the Sun near Mars may not.
The “main belt comet” classification is fairly new, and comet 238P/Read is one of three objects that help form the near-Earth family of comets. Astronomers aren’t sure if this icy object can also stick to frozen water. This is the first solid proof they can.
Observing a comet in such detail is a remarkable achievement for a powerful space telescope, and marks the first time gas has been confirmed in the main comet belt.
“Our world full of water, teeming with life and unique in the universe as far as we know, is something of a mystery – we’re not sure how all that water got here,” study co-author and Webb deputy project scientist for Planetary Sciences Stephanie Milam said in his release. “Understanding the history of water distribution in the solar system will help us understand other planetary systems and whether they are on their way to hosting Earth-like planets.”
The team will now aim to look beyond Comet 238P/Read to see if similar rare comets have a similar composition. This may include more observations with JWST and other telescopes as well as missions in place that can already collect samples from main belt comets.
“These asteroid belt objects are small and dim, and with JWST we can finally see what’s going on with them and draw some conclusions,” said Heidi Hamill, co-author and astronomer at Universities in Research Astronomy (AURA). “Are other main belt comets also deficient in carbon dioxide? Either way, it will be interesting to find out.”
The team’s research is published in a journal alam (Opens in a new tab).
2023-05-15 21:33:33
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