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Simple telescopes discover new planet
(Agencies)
Updated: 2004-08-26 07:30
Astronomers using telescopes not much larger than the spyglass Galileo
wielded 400 years ago have discovered a new Jupiter-sized planet orbiting a
bright, distant star.
It is the first planet to be discovered by an international network of
astronomers using telescopes no larger than those sold at Wal-Mart for the same
price as an iPod.
"This portends a new era in planet hunting," said Geoff Marcy of the
University of California-Berkeley, whose team has discovered nearly 60 new
planets, but was not involved in this survey.
It was only a decade ago that the world's most sophisticated telescopes with
mirrors more than 30 feet across were beginning to notice celestial hints — a
star's wiggle here, a brief dimming there — that planets orbit stars far beyond
our solar system.
Now telescopes with optics just 4 inches wide are scanning the heavens for
signs of these new worlds. The instruments are custom-built, but they use some
commercially available parts also found in department store telescopes that cost
a few hundred dollars.
Still, the discovery suggests it won't be long before the hunt is joined by
backyard astronomers armed with off-the-shelf equipment, loads of time and
enough caffeine to stay awake. Just last winter a Kentucky man in his backyard
found a new nebula, or star nursery, that had been overlooked by scientists at
major observatories.
"You might think that you need a big telescope to do this, but that's not
really true," said Guillermo Torres of the Harvard-Smithsonian Center for
Astrophysics in Cambridge, Mass.
Torres is one of 12 astronomers from six institutions that collaborated to
find the new planet. Details are online in Astrophysical Journal Letters.
"The follow-up work requires very specialized techniques, so this is
something that most people couldn't buy in a shop and do right away," Torres
said. "But the hardware is fairly simple."
Other planet hunters say the small telescopes' success is "quite significant"
because it makes the search cheaper and simpler, which could accelerate the pace
of planet discoveries.
"But you still need automated telescopes to really cut down the operating
costs," said University of Texas astronomer William Cochran, who recently
spotted a new planet using the Hobby-Eberly Observatory in west Texas, which
combines 91 hexagonal mirrors to form a light-gathering surface 30 feet across.
Planet-hunting beyond our solar system is perhaps the most glamorous race in
astronomy, with at least 123 identified.
In a separate announcement Wednesday, European astronomers said they had
discovered yet another new planet using more conventional techniques. Their new
planet is interesting, they said, because its dimensions are more Earth-like. It
is the second planet to be found orbiting a star in the constellation Altar 50
light-years from Earth.
But it is the new "little telescope that could" method that has researchers
buzzing.
The new planet in the constellation Lyra 500 light-years from Earth was the
first to be spotted by the Trans-Atlantic Exoplanet Survey. (An exoplanet is one
that orbits a star other than the sun.)
Small telescopes assembled with off-the-shelf parts were set up at Palomar
Mountain in California, the Lowell Observatory in Arizona and Astrophysical
Institute of the Canary Islands near Africa. The instruments examined 12,000
bright stars over a three-year period.
The telescopes looked for a brief dimming in a star's brightness, indicating
a planet might have moved across the star's face. This method previously has
been used to confirm planet sightings, but this is the first time it has been
used to detect a new planet using such modest instruments, researchers said.
The sophisticated technique has been compared to standing in Boston and
spotting the shadow of a mosquito flying in front of a searchlight in New York
City.
"All that we have to work with is the light that comes from the star," said
study co-author Timothy Brown of the National Center for Atmospheric Research in
Boulder, Colo. "It's much harder to learn anything when the stars are faint.
"The fact that we can learn anything at all from a planet that is 500
light-years away is astonishing," Brown said in a statement.
Astronomers confirmed the discovery by using the giant Keck I telescope in
Hawaii, following the established method of planet detection that measures how a
planet's gravitational tug makes a star wobble ever so slightly.
The new planet, known as TrES-1 (pronounced Trace One) is a hot,
Jupiter-sized gas giant orbiting just 4 million miles from a star in Lyra. By
comparison, Earth is positioned 93 million miles from the sun. It zips around
its star in 72 hours, meaning a year on the planet equals just three days on
Earth.
"This planet is nothing like our own solar system," Torres said. "It's really
close to the parent star. Why hasn't it evaporated? There are a lot of questions
forming about this planet."
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