James Webb Space Telescope Feed Post

Comet 238P/Read (NIRCam Image)

This image of Comet 238P/Read was captured by the NIRCam (Near-Infrared Camera) instrument on NASA’s James Webb Space Telescope on September 8, 2022. It displays the hazy halo, called the coma, and tail that are characteristic of comets, as opposed to asteroids. The dusty coma and tail result from the vaporization of ices as the Sun warms the main body of the comet. Comet Read was among three objects used to define the category of main belt comets in 2006. Before that, comets were understood to reside in the Kuiper Belt and Oort Cloud, beyond the orbit of Neptune, where their ices were preserved farther from the Sun. Since that time scientists have sought to confirm the presence of sublimating material in main belt comets, proving that their coma and tail were due to the same processes that other comets exhibit. With the detection of water vapor on Comet Read, Webb’s sensitive NIRSpec (Near-Infrared Spectrograph) instrument has achieved this goal. Credit: STScI