Water Detected on Jupiter-like Planet Outside of Our Solar System

Astronomers have detected water in the atmosphere of a Jupiter-like planet outside of our solar system using a technique that will further enhance our understanding of how many planets with water exist throughout the universe.

Writing the in The Astrophysical Journal Letters, the researchers describe the planet that orbits around the nearby star tau Boötis.

The planet, designated tau Boötis b, is as massive as Jupiter, but much hotter, said Chad Bender, a research associate in the Penn State Department of Astronomy and Astrophysics and a co-author of the paper. Hot-Jupiter planets like tau Boötis b do not exist in our solar system.

"Our detection of water in the atmosphere of tau Boötes b is important because it helps us understand how these exotic hot-Jupiter planets form and evolve," Bender said. "It also demonstrates the effectiveness of our new technique, which detects the infrared radiation in the atmospheres of these planets."

This new technique, the researchers contend, could be useful in detecting water on exoplanets that previous observations have missed or been unable to see altogether.

Water has only been found on a handful of planets, and the techniques used to detect it require the planet to be quite far from its parent star or demand the planet has an orbit that passes in front of its host star while visible from Earth.

As a result, many exoplanets where water could exist have not been conclusively examined.

"We now are applying our effective new infrared technique to several other non-transiting planets orbiting stars near the Sun," Bender said. "These planets are much closer to us than the nearest transiting planets, but largely have been ignored by astronomers because directly measuring their atmospheres with previously existing techniques was difficult or impossible."

This new technique will allow astronomers to search for water on much cooler planets that are more distant from their host stars, a position where water is more likely to exist.