Monday, September 22, 2008

Is It a Planet? Who Know's


Astronomers from the University of Toronto have published a picture of what they say might be the first image of a planet orbiting another Sunlike star.

The planet, according to their observations, is 7 to 12 times as massive as Jupiter and is about 30 billion miles from a star known as 1RXS J160929.1-210524, about 500 light-years away in the constellation Scorpius.

The picture was taken last spring by the 270-inch diameter Gemini North Telescope on Hawaii’s Mauna Kea, using so-called adaptive optics to reduce atmospheric blurring and thus sharpen the images of both star and planet.

This is at least the third so-called exoplanet candidate that astronomers have photographed. In 2004, a group from the European Southern Observatory in Chile photographed a red speck about five times the mass of Jupiter orbiting a kind of failed star known as a brown dwarf in the constellation Hydra.

In 2005, another group photographed an object that they estimated to be twice as massive as Jupiter orbiting the star GQ Lupi, but other astronomers said the object could be as much as 36 Jupiters in mass, making it not a planet but a brown dwarf.

The Toronto astronomers say it will take several years to determine whether their planet is moving through space with the star and thus is really a planet. In the meantime, theorists can puzzle about how it could come to live 60 times farther from its star than Jupiter is from the Sun.

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