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Whitney Clavin Jet Propulsion Laboratory, (818) 354-4673
Erica Hupp/Grey Hautaluoma Headquarters, (202) 358-1237/0668
News Release: 2006-049
NASA's Spitzer Finds Hints of Planet Birth Around Dead Star
NASA's Spitzer Space Telescope has uncovered new evidence that planets might rise up out of a dead star's ashes.
The infrared telescope surveyed the scene around a pulsar, the remnant of an exploded star, and found a surrounding disk made up of debris shot out during the star's death throes. The dusty rubble in this disk might ultimately stick together to form planets.
This is the first time scientists have detected planet-building materials around a star that died in a fiery blast.
"We're amazed that the planet-formation process seems to be so universal," said Dr. Deepto Chakrabarty of the Massachusetts Institute of Technology in
A paper on the Spitzer finding appears in the April 6 issue of Nature. Other authors of the paper are lead author Zhongxiang Wang and co-author David Kaplan, both of the Massachusetts Institute of Technology.
The finding also represents the missing piece in a puzzle that arose in 1992, when Dr. Aleksander Wolszczan of
The pulsar observed by Spitzer, named 4U 0142+61, is 13,000 light-years away in the Cassiopeia constellation. It was once a large, bright star with a mass between 10 and 20 times that of our sun. The star probably survived for about 10 million years, until it collapsed under its own weight about 100,000 years ago and blasted apart in a supernova explosion.
Some of the debris, or "fallback," from that explosion eventually settled into a disk orbiting the shrunken remains of the star, or pulsar. Spitzer was able to spot the warm glow of the dusty disk with its heat-seeking infrared eyes. The disk orbits at a distance of about 1 million miles and probably contains about 10 Earth-masses of material.
Pulsars are a class of supernova remnants, called neutron stars, which are incredibly dense. They have masses about 1.4 times that of the sun squeezed into bodies only 10 miles wide. One teaspoon of a neutron star would weigh about 2 billion tons. Pulsar 4U 0142+61 is an X-ray pulsar, meaning that it spins and pulses with X-ray radiation.
Any planets around the stars that gave rise to pulsars would have been incinerated when the stars blew up. The pulsar disk discovered by Spitzer might represent the first step in the formation of a new, more exotic type of planetary system, similar to the one found by Wolszczan in 1992.
"I find it very exciting to see direct evidence that the debris around a pulsar is capable of forming itself into a disk. This might be the beginning of a second generation of planets," Wolszczan said.
Pulsar planets would be bathed in intense radiation and would be quite different from those in our solar system. "These planets must be among the least hospitable places in the galaxy for the formation of life," said Dr. Charles Beichman, an astronomer at NASA's Jet Propulsion Laboratory and the California Institute of Technology, both in
The Jet Propulsion Laboratory manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the
For more information about Spitzer, visit:
www.spitzer.caltech.edu/spitzer
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