JWST finds water around rare comet but scientists are puzzled
The James Webb Space Telescope (JWST) has detected water around a rare comet lying in the main asteroid belt between Jupiter and Mars. This discovery represents yet another scientific breakthrough for the powerful space observatory. This was the first time that gas, particularly water vapor, was found around a comet in the main asteroid belt. But the finding has puzzled scientists. Let's see why.
Why does this story matter?
Thanks to Webb's infrared capabilities, scientists can see farther into the universe than ever before. The latest finding is crucial and puzzling at the same time. One of the reasons that make the discovery significant is that it indicates that water in the early solar system could have been preserved as ice in the main asteroid belt.
The comet does not have carbon dioxide
Along with the discovery of water vapor, the study of the comet, named 238P/Read, also comes with a mystery. Unlike other comets, Comet 238P/Read does not have carbon dioxide, something researchers expected to find. Usually, carbon dioxide constitutes roughly 10% of the volatile material in a comet, which is easily vaporized due to the heat from the Sun.
Why doesn't the comet have carbon dioxide?
There are two plausible reasons why Comet 238P/Read lacks carbon dioxide. One explanation is that Comet 238P/Read might have had carbon dioxide during its formation but lost it because of warming temperatures, due to the Sun. The other theory is that the comet might have formed in a "particularly warm pocket of the solar system," where carbon dioxide was not available.
'Main belt comets' are a fairly new classification
The main belt asteroid, along with being home to asteroids, also hosts comets like 238P/Read. 'Main belt comets' are a fairly new classification, and Comet 238P/Read was one of the original three comets used to establish the category, explained NASA in a blog post. These cosmic bodies are known for displaying a halo of material or coma, and tail like a comet.
Why do comets have a distinctive coma and tail?
A comet's coma and tail come from frozen material which transforms into gas as they approach the Sun. It is believed that comets come from the Kuiper Belt and Oort Cloud, which lies beyond the orbit of Neptune at the edge of the solar system. These locations would allow the icy material of comets to be preserved from the radiation from the Sun.
Researchers theorized ice could be preserved in warmer asteroid belt
However, scientists also believed that water ice could be preserved in the "warmer asteroid belt," lying inside the orbit of Jupiter but there was no definitive evidence until Webb's recent findings.
'It's water ice that is creating that effect'
"In the past, we've seen objects in the main belt with all the characteristics of comets, but only with this precise spectral data from Webb can we say yes, it's definitely water ice that is creating that effect," said Michael Kelley, the study's lead author. Webb's observations "demonstrate that water ice from the early solar system can be preserved in the asteroid belt."
Researchers hope to bring back comet samples in future
Taking the study further, researchers hope to look beyond Comet 238P/Read to see if other main belt comets have similar compositions. Interestingly, the team wants to bring back samples from these comets via future missions.
