- AUSTIN, Texas (Reuters) - Astronomers said Saturday they have found
two new planets orbiting stars outside our solar system, and more so-called
extrasolar planets could be discovered within months.
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- Neither one of the newly discovered planets
is a place humans would want to call home: they are big, gassy and much
too close to their stars for earthly comfort. But the scientists who found
them believe the discovery of an Earth- like planet is possible.
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- ''I think we're smarter than we were
about how to find planets,'' Debra Fischer, the planets' discoverer, told
a meeting of the in Austin. ''With a sample of suitable stars and enough
telescope time, we expect to find planets around about 2 percent of Sun-like
stars within a few months.''
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- Astronomers have long presumed the existence
of planets in other solar systems, and the first such planets were identified
in 1995 by Geoffrey Marcy. Both Fischer and Marcy are with San Francisco
State University.
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- Since then, planetary discoveries have
quickened, and the two newcomers bring the total of known extrasolar planets
to 17.
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- The new planets cannot be seen, but can
be inferred by the gravitational pull they exert on the stars they circle.
Stars with big planets around them have a distinctive wobble detectable
from Earth.
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- Fischer found the two new planets among
a group of 88 Sun-like stars using the 3-meter telescope at Lick Observatory
near San Jose, California. These 88 stars were part of a survey of 200
stars that Fischer began last summer.
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- Both newly identified planets are giants:
one is 3.5 times the mass of Jupiter, the largest planet in Earth's solar
system, and the other has 1.3 times Jupiter's mass, Fischer and her colleagues
announced.
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- Fischer said she and other planet hunters
will continue to look for solar systems that might contain Earth-like planets.
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- ''We want smaller planets that are farther
away from their host stars, because we want to probe the habitable zone
of stars -- the place where life may form,'' she said in the statement.
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- The more massive new planet, known to
astronomers as HD195019, is located in the constellation Delphinus; the
less massive one, HD217107, is in Pisces.
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- Another group of researchers found that
a cluster of stars near our solar system may be good candidates for harboring
big gassy planets, because they have high concentrations of heavy elements
-- those heavier than hydrogen and helium.
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- An international team of astronomers,
including Guillermo Gonzalez of the University of Washington in Seattle,
studied a dozen stars orbited by Jupiter- mass planets and found that all
12 had an abundance of heavy elements.
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