Planet Outside Solar System Confirmed
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An international team of
astronomers has confirmed the
discovery of a giant planet,
approximately five times the mass
of Jupiter, that is orbiting a young
brown dwarf.
It's the first time that a planet
outside of our solar system has
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The giant planet (center) orbiting a young
brown dwarf.
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Scientists early this year took new images of the two objects with the Very
Large Telescope in northern Chile. The planet, known as an exoplanet, is
located near the southern constellation of Hydra about 200 light years from
Earth.
"Our new images show convincingly that this really is a planet, the first planet
that has ever been imaged outside of our solar system," said Gael Chauvin,
astronomer at the European Southern Observatory (ESO) and leader of the
team of astronomers who conducted the study.
Astronomers who observed the young brown dwarf and its giant planet
companion for a year found the two objects to be gravitationally bound to each
other and moving together.
The new images confirm their findings. "I'm more than 99 percent confident.
This is also the first time that a planet outside of our solar system has been
detected far from a star or brown dwarf — nearly twice as far as the distance
between Neptune and the sun,"said Benjamin Zuckerman, UCLA professor of
physics and astronomy and a member of the team.
Anne-Marie Lagrange, another member of the team from the Grenoble
Observatory in France, said, "Our discovery represents a first step towards one
of the most important goals of modern astrophysics: to characterize the
physical structure and chemical composition of giant and, eventually,
terrestrial-like planets."
The object was first spotted as a faint reddish speck of light, now called
2M1207b, in the close vicinity of a young brown dwarf in September. Model
calculations led scientists to conclude that it was a planet.
But at the time of the discovery, it was difficult to prove that the faint source was
not a background object (such as an unusual galaxy or a peculiar cool star
with abnormal infrared colors), even though this appeared very unlikely.
"Given the rather unusual properties of the 2M1207 system, the giant planet
most probably did not form like the planets in our solar system," Chauvin said.
"Instead it must have formed the same way our sun formed, by a one-step
gravitational collapse of a cloud of gas and dust."
The estimated mass of the companion is between 13 and 14 times the mass
of Jupiter, which places the companion right on the borderline between
massive planets and the lowest mass brown dwarfs.
"Remarkably, this companion is located very far from its host star — about
nine times farther from AB Pictoris than Neptune is from the sun," Zuckerman
said. Nothing so far from its star has ever been seen in a planetary system
before, he added.
Brown dwarfs, the missing link between gas giant planets like Jupiter and
small, low‑mass stars, are failed stars about the size of Jupiter, with a much
larger mass — but not quite large enough to become stars.
Like the sun and Jupiter, they are composed mainly of hydrogen gas, perhaps
with swirling cloud belts. They emit almost no visible light.
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