spacer spacer spacer
spacer spacer spacer
NASA Logo - Jet Propulsion Laboratory    + View the NASA Portal Search JPL
JPL Home Earth Solar System Stars & Galaxies Technology
spacer Jet Propulsion Laboratory spacer
spacer   spacer

10th Planet Discovered - July 29, 2005 Media Telecon

A toll-free recording of today's telecon will be available until August 6.
The number is 866-433-1148.

Teleconference Image

These time-lapse images of a newfound planet in our solar system, called 2003UB313, were taken on Oct. 21, 2003, using the Samuel Oschin Telescope at the Palomar Observatory near San Diego, Calif. The planet, circled in white, is seen moving across a field of stars. The three images were taken about 90 minutes apart.

Scientists did not discover the planet until Jan. 8, 2005.

Image credit: Samuel Oschin Telescope, Palomar Observatory
+ Highest resolution available

Teleconference Image

Newest Member of our Solar System

This artist's concept shows the planet catalogued as 2003UB313 at the lonely outer fringes of our solar system. Our Sun can be seen in the distance. The new planet, which is yet to be formally named, is at least as big as Pluto and about three times farther away from the Sun than Pluto. It is very cold and dark. The planet was discovered by the Samuel Oschin Telescope at the Palomar Observatory near San Diego, Calif., on Jan. 8, 2005.

Image credit: NASA/JPL-Caltech
+ Highest resolution available

+ Browse image
+ High resolution

Mike Brown
Professor of Planetary Astronomy
Division of Geological and Planetary Sciences
California Institute of Technology, Pasadena

Michael Brown heads the California Institute of Technology (Caltech) Planetary Astronomy Group. He is a planetary science professor who investigates the solar system and the solar neighborhood, primarily through observational methods, both surface and spacecraft-based.

Areas of research investigated by the undergraduate, graduate, and post-doctoral members of his group include extra-solar planetary systems (from brown dwarfs to stellar disks), ( Kuiper Belt Objects, icy satellites), the planetary satellites , and the occasional inner solar system body . Brown received a bachelor's degree in Physics from Princeton University , N.J. , in 1987 and a Ph.D. from the University of California at Berkeley in 1994.

PASADENA , CALIF. 91109 TELEPHONE (818) 354-5011

Jane Platt 818/354-0880
Jet Propulsion Laboratory, Pasadena , Calif.

Dolores Beasley 202/358-1753
Headquarters, Washington                   

Robert Tindol  (626) 395-3631
California Institute of Technology, Pasadena , Calif.

NEW RELEASE: 2005-126 July 29, 2005


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:


For information about NASA and agency programs on the Web, visit: .




spacer spacer spacer
Privacy / Copyrights FAQ Contact JPL Sitemap
spacer spacer spacer
FIRST GOV + Freedom of Information Act NASA Home Page
Site Manager:
  Susan Watanabe
Tony Greicius, Jason Heidecker,
Andrew Rader
spacer spacer spacer
spacer spacer spacer