Team Records Glow From Distant Planets

A NASA telescope peering beyond our solar system has for the first time directly measured light from two Jupiter-size gas planets closely orbiting distant stars, adding crucial features to astronomy’s portrait of faraway worlds.

Studies of the infrared light streaming from the two planets suggest they are made of hot gases, reaching a broiling 1,340 degrees Fahrenheit or higher.

“It’s an awesome experience to realize we are seeing the glow of distant worlds,” said astronomer David Charbonneau of the Harvard- Smithsonian Center for Astrophysics in Cambridge, Mass., whose team captured light from a planet in the constellation Lyra. “The one thing they can’t hide is their heat.”

Since the mid-1990s, scientists have discovered more than 130 extrasolar planets, but the stars they orbit tend to overwhelm the view of the planets.

To find them, astronomers indirectly measure the tiny gravitational wobble that orbiting planets exert on their suns or the brief dimming of starlight that occurs when a planet’s orbit carries it in front of the star.

One planet is known as HD 209458b, nicknamed Osiris. It orbits a sunlike star 150 light-years from Earth in the constellation Pegasus. Its infrared signature was measured at the NASA Goddard Spaceflight Center in Greenbelt, Md. Details will appear today in the online version of the journal Nature.

The other extrasolar planet measured by the Harvard-Smithsonian team is known as TRes-1. It is 500 light-years from Earth in the constellation Lyra. Results will be published in the June 20 issue of Astrophysical Journal.