Water Detected in Atmosphere of Planet Orbiting Tau Bootis

Posted on February 25, 2014

Water has been detected in the atmosphere of a planet orbiting tau Boötis, which is about 51 light-years away from Earth. The planet, tau Boötis b, has a mass over four times that of Jupiter and is closer to its star than Mercury is to the Sun. The discovery was made by astronomers from Penn State University and other institutions. The researchers say the technique could help researchers learn how many planets with water exist throughout the universe.

Chad Bender, a research associate in the Penn State Department of Astronomy and Astrophysics and a co-author of the paper, says in a statement, "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."

Scientists previously had detected water vapor on a handful of other planets, using a technique that works only if a planet has an orbit that passes it in front of its star, when viewed from Earth. Another technique only works if the planet is sufficiently far away from its host star. The new infrared technique works on non-transiting planets. The astronomers expect that future telescopes, like the James Webb Space Telescope, will enable astronomers to examine the atmospheres of planets that are much cooler and more distant from their host stars. Astronomers say liquid water is even more likely to exist on these exo-planets.

Bender says, "We now are applying our effective new infrared technique to several other non-transiting planets orbiting stars near the Sun. 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."

The research paper was published here in The Astrophysical Journal Letters.



More from Science Space & Robots