Comet 238P/Read spends its lifetime much closer to the Sun than most comets in the asteroid belt, yet has managed to hold on to its water, according to recent observations by the James Webb Space Telescope.
"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," says Michael Kelley from the University of Maryland, who led the study.
But while 238P/Read’s water might have survived the relative warmth of the asteroid belt, the same does not appear to be true for its carbon dioxide.
The molecule usually makes up 10 per cent of similar comets, but JWST failed to find any on 238P/Read.
This could be because carbon dioxide vapourises more easily than water ice or it could indicate that 238P/Read formed in a warm pocket of the Solar System, free from carbon dioxide.
The team hopes to determine which is more likely by observing other main belt comets.
"Do other main belt comets also lack carbon dioxide? Either way it will be exciting to find out," says Heidi Hammel, lead for JWST’s guaranteed time observations of Solar System objects.
