Hubble Space Telescope image of the interstellar comet 2I/Borisov. The image was taken by Hubble's Cosmic Origins Spectrograph which is sensitive to ultraviolet light and detected carbon monoxide, oxygen and water forming a gas cloud around the nucleus as the comet neared the Sun. The gas from 2I/Borisov contained a high amount of carbon monoxide gas compared to any other comet entering the inner solar system. 2I/Borisov originates from outside of the Solar System and the abundance of carbon monoxide ice suggests it formed in a carbon-rich disk of icy debris around a red dwarf star.