September 12, 2006
(PLANETQUEST) -- A rare planet circling a star 500 light-years away has been spotted by astronomers using a telescope whose development was funded by NASA. The discovery provides a new target that can be followed up with observations by amateur astronomers, as well as by future planet-finding space missions.
"The most exciting part is that we have now identified a planet in the field of view of NASA's Kepler mission," said David Charbonneau, a co-author of the paper announcing the discovery. Kepler, scheduled to launch in 2008, will stare at a single patch of sky for four years in a search for distant planets. The newly discovered planet is slightly larger than Jupiter.
"Kepler will be able to make very precise measurements of this planet, look for the presence of moons and rings around this planet and measure its reflected light," Charbonneau said.
Of the nearly 200 extrasolar planets discovered so far, only 10 have been found transiting, or passing directly in front of, the host star. Such planets make especially valuable targets for astronomers because the starlight passing behind the planet can enable measurement of the planet's density and atmospheric makeup.
Michael Devirian of JPL, manager of NASA's Navigator Program, said the discovery shows that NASA's investment in precursor science for its planet-finding missions is paying off. NASA's Navigator Program is focused on advanced telescope searches for habitable planets and life around other stars.
"The Navigator Program provided the early funding for the 'Sleuth' telescope, which has now produced this exciting discovery," Devirian said. "Findings like this will help pave the way for investigations to be conducted later by the SIM PlanetQuest and Terrestrial Planet Finder missions."
Charbonneau describes Sleuth as "a very humble telescope," equipped with a 4-inch camera lens and a digital camera. Located at California's Palomar Observatory, the Sleuth routinely scans the sky, searching for transit signals - the slight dip in a star's brightness caused by objects passing in front of it.
"The trick is, we don't need a very big telescope, but we need to look at the sky all the time. We've built a robot telescope that every night goes to the right part of the sky and takes images continuously. We use a variety of computer codes to search through all the data. It's this mountain of data and we have the needle in the haystack problem, looking for these little signals."
It was one such "little" signal that proved to be a new planet, which passes in front of its host star every two-and-a-half days. The team, led by Charbonneau and Francis O'Donovan, a graduate student at Caltech, confirmed the discovery by conducting follow-up observations with the giant W.M. Keck Observatory, located in Hawaii.
"This was one of those rare discovery moments...while we were at Keck, we actually confirmed it was a planet, so we drank a little champagne in the observatory," Charbonneau recounts.
The Sleuth telescope is part of the Trans-Atlantic Exoplanet Survey (TrES), with several other small telescopes performing similar ongoing observations at different locations. The new planet "TrES-2," is named after the survey. O'Donovan is lead author of the paper, which will be published in an upcoming edition of the Astrophysical Journal. JPL's John Trauger is also listed among the authors.
Written by Randal Jackson/PlanetQuest
