Hubble Uncovers Water Vapor In Small Exoplanet’s Atmosphere

Astronomers using NASA’s Hubble Space Telescope have observed water vapor in the atmosphere of the smallest exoplanet ever detected. Located 97 light-years away, planet GJ 9827d is approximately twice the size of Earth.

This finding raises the possibility of other planets with water-rich atmospheres in our galaxy. However, it remains uncertain whether the observed water vapor is in a hydrogen-rich atmosphere or if the planet's atmosphere is predominantly water.
Water on a planet this small is a landmark discovery, pushing us closer than ever to characterizing truly Earth-like worlds, and thanks to the Hubble Space Telescope we’ll be able to continue our search for more planets like our own.