The Hindu : International : It's a huge new planet

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Sunday, May 01, 2005

International

International

It's a huge new planet

For the first time, an extra-solar planet is pictured

BREAKTHROUGH: The first planet outside the solar system or very low-mass brown dwarf, lower left, orbits AB Pictoris, a young star located about 150 light years from the earth. This image was released by the European Southern Observatory. — Photo: AP

LOS ANGELES: New images taken of an object five times the mass of Jupiter confirm that it is a giant planet closely orbiting a distant star, an international team of astronomers reported.

The team of European and American astronomers said this is the first time a planet outside of our solar system has been directly observed. This is, however, a claim other scientists have also made.

The team first spotted the object last year as a faint reddish speck of light circling a dim brown dwarf — or failed star — 225 light-years away from the earth near the constellation Hydra.

At that time, scientists guessed the faint light was a planet, but said further observation was needed.

The discovery touched off a debate over whether the object was actually a planet or a background star. Since the mid-1990s, scientists have discovered more than 130 of these so-called extra-solar planets, or exoplanets, by indirect means, but observing them directly has proved difficult.

Convincing images

Refined images taken earlier this year by the Very Large Telescope in northern Chile show two separate objects bound by gravity moving together, according to Gael Chauvin, an astronomer at the European Southern Observatory, who led the team. "Our new images show convincingly that this really is a planet, the first planet that has ever been imaged outside of our solar system," Dr. Chauvin said in a statement.

Added Benjamin Zuckerman, an astronomer at the University of California, Los Angeles (UCLA), who was part of the team: "I'm more than 99 per cent confident."

Dr. Chauvin's team estimated the mass of the object, called 2M1207b, by measuring its brightness. They found that it was five times the mass of Jupiter and orbited a brown dwarf, known as 2M1207A, at a distance nearly twice as far as Neptune is from the sun. Their observations will be published in a future issue of Astronomy and Astrophysics.

Lynne Hillenbrand, an Assistant Professor of Astronomy at the California Institute of Technology, said the findings were intriguing, but cautioned against calling the object a planet. "The claim of an object being a planet is subject to one's definition of planet and there are different camps on what that definition is," she said.

In recent months, different groups of astronomers have published competing claims about directly observing extra-solar planets.

On the Net, the European Southern Observatory is at http://www.eso.org while UCLA is at http://www.ucla.edu — AP

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