Astronomers have taken what may the first picture of a planet orbiting a star similar to the sun.
This distant world is giant (about eight times the mass of Jupiter) and lies far out from its star (about 330 times the Earth-Sun distance). But for all the planet’s strangeness, its star is quite like our own sun.
Previously, the only photographed extrasolar planets have belonged to tiny, dim stars known as brown dwarfs. And while hundreds of exoplanets have been detected by noting their gravitational tug on their parent stars, it is rare to find one large enough to image directly.
"This is the first time we have directly seen a planetary mass object in a likely orbit around a star like our sun," said David Lafreni�re, an astronomer at the University of Toronto who led the team that discovered the star. "If we confirm that this object is indeed gravitationally tied to the star, it will be a major step forward."
Further study will be needed to prove that the planet is in fact orbiting around the star, as opposed to the possibility, however unlikely, that the two objects just happen to lie in the same area of the sky at roughly the same distance from us.
"Of course it would be premature to say that the object is definitely orbiting this star, but the evidence is extremely compelling," Lafreni�re said. "This will be a very intensely studied object for the next few years!"
The researchers used the Gemini North telescope on Mauna Kea in Hawaii to glimpse the planet and its star, 1RXS J160929.1-210524, which lies about 500 light-years from Earth. Though the star has about 85 percent the mass of the sun, it is younger than our star. In order to image the far-flung system, the team utilized adaptive optics technology, which uses flexible mirrors to offset the distortion light suffers as it passes through Earth’s atmosphere.
The strange planet so far from its parent star is unexpected based on current theories of star and planet formation. For comparison, the farthest planet in our solar system, Neptune, lies only 30 times the Earth-sun distance away from the sun.
"This discovery is yet another reminder of the truly remarkable diversity of worlds out there, and it’s a strong hint that nature may have more than one mechanism for producing planetary mass companions to normal stars," said team member Ray Jayawardhana, also of the University of Toronto.
The distant exoplanet, at about 1,800 Kelvin (about 1,500C), is also much hotter than our own Jupiter, which has a temperature of about 160 Kelvin (-110C).
The team discovered the new planet as part a survey of more than 85 stars in the Upper Scorpius association, a group of young stars formed about 5 million years ago.
source:http://news.yahoo.com/s/space/20080915/sc_space
