Dwarf planet Ceres is located in the main asteroid belt, between the orbits of Mars and Jupiter, as illustrated in this artist's conception. Observations by the Herschel space observatory between 2011 and 2013 find that the dwarf planet has a thin water vapor atmosphere. This is the first unambiguous detection of water vapor around an object in the asteroid belt.
Illustration credit: ESA/ATG medialab
Note: For more information, see PIA17831: Water Detection on Ceres, Herschel Telescope Detects Water on Dwarf Planet, Herschel Discovers Water Vapor Around Dwarf Planet Ceres, and Water Detected on Dwarf Planet Ceres.