New Release: 2005-126 July 29, 2005=20
NASA-Funded Scientists Discover Tenth Planet
A planet larger than Pluto has been discovered in the outlying
regions of the solar system.
The planet was discovered using the Samuel Oschin Telescope at Palomar
Observatory near San Diego, Calif. The discovery was announced today
by planetary scientist Dr. Mike Brown of the California Institute of
Technology in Pasadena, Calif., whose research is partly funded by
NASA.
The planet is a typical member of the Kuiper belt, but its sheer size
in relation to the nine known planets means that it can only be
classified as a planet, Brown said. Currently about 97 times further
from the sun than the Earth, the planet is the farthest-known object
in the solar system, and the third brightest of the Kuiper belt
objects.
"It will be visible with a telescope over the next six months and is
currently almost directly overhead in the early-morning eastern sky,
in the constellation Cetus," said Brown, who made the discovery with
colleagues Chad Trujillo, of the Gemini Observatory in Mauna Kea,
Hawaii, and David Rabinowitz, of Yale University, New Haven, Conn.,
on January 8.
Brown, Trujillo and Rabinowitz first photographed the new planet with
the 48-inch Samuel Oschin Telescope on October 31, 2003. However, the
object was so far away that its motion was not detected until they
reanalyzed the data in January of this year. In the last seven months,
the scientists have been studying the planet to better estimate its
size and its motions.
"It's definitely bigger than Pluto," said Brown, who is a professor
of planetary astronomy.
Scientists can infer the size of a solar system object by its
brightness, just as one can infer the size of a faraway light bulb
if one knows its wattage. The reflectance of the planet is not yet
known.
Scientists can not yet tell how much light from the sun is reflected
away, but the amount of light the planet reflects puts a lower limit
on its size.
"Even if it reflected 100 percent of the light reaching it, it would
still be as big as Pluto," says Brown. "I'd say it's probably one and
a half times the size of Pluto, but we're not sure yet of the final
size.
"We are 100 percent confident that this is the first object bigger
than Pluto ever found in the outer solar system," Brown added.
The size of the planet is limited by observations using NASA's Spitzer
Space Telescope, which has already proved its mettle in studying the
heat of dim, faint, faraway objects such as the Kuiper-belt bodies.
Because Spitzer is unable to detect the new planet, the overall
diameter must be less than 2,000 miles, said Brown.
A name for the new planet has been proposed by the discoverers to the
International Astronomical Union, and they are awaiting the decision
of this body before announcing the name.
The Jet Propulsion Laboratory manages the Spitzer Space Telescope
mission for NASA's Science Mission Directorate, Washington. Science
operations are conducted at the Spitzer Science Center at Caltech.
Caltech manages JPL for NASA.
For more information and images see:
http://www.nasa.gov/vision/universe/solarsystem/newplanet-072905-images.html
or
http://www.astro.caltech.edu/palomarnew/sot.html |
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