Exoplanet atmosphere contains water vapor

Astronomers have detected water vapor in the atmosphere of an exoplanet — an extrasolar planet, which does not orbit the Sun.

The planet is the size of Neptune and about four times the size of Earth. It orbits a star some 130 light years from Earth.

HAT-P-11b’s atmosphere was also found to contain copious amounts of hydrogen.

Atmospheres are telltales of a planet’s formation and a guide to what is happening on its surface.

Dr Eliza Kempton from Grinnell College, Iowa, has said, “Astronomers have detected water vapour in the atmospheres of larger planets – planets that are closer in size to Jupiter. But you can imagine that eventually we want to be able to detect molecules in the atmospheres of even smaller planets.

“We’d like to be able to look at an Earth-sized planet and measure its gaseous composition. So this is a step on the ladder; we’re stepping down the ladder towards smaller and smaller planets,” she has noted.