Researchers Detect Water in the Atmosphere of a Jupiter-Sized Alien Planet

A team of researchers has detected water in the atmosphere of a planet located outside our solar system.

Using a novel technique, a team of researchers at the Penn State University has detected water in the atmosphere of a planet that is as enormous as Jupiter and is seen orbiting the nearby star, tau Bootis.

"Planets like tau Boötes b, which are as massive as Jupiter but much hotter, 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. It also demonstrates the effectiveness of our new technique, which detects the infrared radiation in the atmospheres of these planets," says Chad Bender, research associate in the Penn State Department of Astronomy and Astrophysics and a co-author of the paper.

Prior to this, researchers detected signs of water on a few other planets. But this is possible only if these planets have an orbit that passes in front of the star, during observations made from Earth. Bu the other technique works even when the planet is located at a far off distance from its host star.

But using these two techniques researchers could not detect water on other extrasolar planets. And for these non-transiting planets orbiting stars near the Sun, the researchers are using a new infrared technique.

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."

Recently, Geoffrey Blake, a professor of cosmoschemistry and planetary science detected carbon monoxide on tau Bootes by using the radio velocity method. 

Combining this novel detection technique along with powerful telescopes such as the James Webb Space Telescope and the Thirty Meter Telescope, the astronomers were able to examine the atmosphere of planets that are much cooler and at a far off distance from their host stars, where the likelihood of the presence of water is higher.

The findings appear in The Astrophysical Journal Letters.