Hubble photo appears to show first planet beyond solar system Object 2 to 3 times size of Jupiter is near its twin 'parent' stars

May 29, 1998|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

WASHINGTON -- The search for alien life in our Milky Way galaxy has advanced another notch with a photograph of what could be the first planet ever seen outside our solar system.

A team of astronomers using the Hubble Space Telescope announced yesterday that they had photographed what appears be a giant gas planet near a double star system 450 light-years from Earth near the constellation Taurus.

Dubbed TMR-1C, the object is two or three times the mass of Jupiter, our solar system's biggest planet. It looks as if it has been kicked out of orbit by its two "parent" stars.

If so, it is doomed to wander forever in deep space, like Earth's lost moon in the 1970s TV series "Space 1999." But unlike the TV moon, inhabited by luckless scientists (Martin Landau and Barbara Bain), TMR-1C is too hot to be inhabited.

Discoverers

TMR-1C was discovered by a team led by Susan Terebey, who heads the private Extrasolar Research Co. in Pasadena, Calif.

"This is part of a journey, exploring the universe and looking for intelligent life," she said. "As technology gets better, we will be able to tell what places may be habitable."

She is scheduled to present her findings before a meeting of the American Astronomical Society next month in San Diego, and is preparing a paper for publication in a scientific journal.

"This is a particularly exciting result, a landmark in our quest to understand our origins," said Steven Strom, an astronomer at the University of Massachusetts at Amherst. Anne Kinney, an astronomer at the Space Telescope Science Institute in Baltimore, called it "a watershed event." Neither was on the discovery team.

Ed Weiler, director of NASA's "Origins" program, said observations to begin in August will determine whether the object really is a planet, an unrelated star in the background sky or something else.

NASA's decision to announce Terebey's discovery before formal peer review and publication of the research breaks with scientific tradition. But Weiler said NASA decided to go public after an abstract of her findings was posted on the Internet in advance of the San Diego meeting.

He said Terebey was first subjected to a 90-minute "grilling" at NASA headquarters by a team of five Ph.D. astronomers. They concluded that her work was sound.

"These are solid assumptions and solid conclusions," he said. "They may not be the right ones, but they are reasonable."

Human beings have wondered for centuries whether life exists elsewhere in the universe. When photographic tours of our solar system failed to find signs of life, the search turned to nearby stars.

The difficulties are enormous. Planets are tiny, dark objects normally lost in the glare of their stars when viewed from tens of light-years away. (A light-year is the distance light travels in one year, about 5.9 trillion miles.)

In 1995, after decades of looking, two Swiss astronomers announced that they had detected a wobble in the motion of a sun-like star called 51 Pegasi, 45 light-years from Earth. The wobble was indirect evidence that 51 Pegasi was being orbited by an unseen planet about half the size of Jupiter.

It was man's first detection of a planet beyond our own solar system. Astronomers have since identified seven other stars with similar wobbles, suggesting the presence of more planets.

No signs of life

The data reveal no signs of life. All of the planets are giants -- from half to 6.6 times Jupiter's mass. Worse, most of them appear to be orbiting much closer to their stars than Earth is to the sun, in regions that are likely to be hostile to life as we know it.

TMR-1C is the first suspected planet to be seen directly. It was discovered by accident in August, as Terebey and her team conducted a survey of young stars forming in a dense cloud of dust and gas in Taurus.

In the image made by Hubble's Near Infrared Camera, the object appears as a glowing dot at the end of an odd filament of dust that extends outward from a pair of twin stars.

Terebey's interpretation, after months of study and work with computer models, is that the twin stars and TMR-1C formed only about 300,000 years ago.

Such multiple-object star systems are complex and unstable. In time, one of the objects is likely to orbit too close to another's gravitational field and be flung off into space.

Terebey's team believes TMR-1C was tossed out 1,000 years ago, leaving the trail of heated dust or gas that is visible in the photo. Only by being tossed so far from the stars' glare has the object become visible.

The exiled planet is now about 130 billion miles from its parent stars -- equivalent to the outermost belt of comets around our solar system -- and flying away at 20,000 mph.

Pub Date: 5/29/98

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