Artist’s concept of Comet 238P/Read

This artist’s concept of Comet 238P/Read shows the main belt comet sublimating—its water ice vapourising as its orbit approaches the Sun. This is significant, as the sublimation is what distinguishes comets from asteroids, creating their distinctive tail and hazy halo, or coma. The NASA/ESA/CSA James Webb Space Telescope’s detection of water vapour at Comet Read is a major benchmark in the study of main belt comets, and in the broader investigation of the origin of Earth’s abundant water.

[Image description: Illustration, close up of rocky body of a comet with detailed, cratered surface. Glowing rays emanate from the rocky surface like sunlight through clouds, representing water ice being vapourised by the heat of the Sun.]