The –est Astronomy

Water found on Neptune-sized world

HAT-P-11b is smallest exoplanet known to host the life-friendly molecule

HAT-P-11b exoplanet illustration

WATER, WATER EVERYWHERE  Roughly the size of Neptune, the planet HAT-P-11b is the smallest known planet to have water. The orange glow of the planet’s sun (upper right in illustration) might lend a magenta tinge to the planet’s atmosphere.

David A. Aguilar/CfA

By Christopher Crockett

- More than 2 years ago

The smallest, coolest exoplanet known to host water is roughly the size of Neptune, astronomers report in the Sept.