6 Prized Pulsar Pair. Astrophysicists doubled their pleasure this year by finding the first known binary system of pulsars: spinning neutron stars that whip tight beams of radiation into space. The system's properties have startled both observers and theorists, one of whom describes the discovery as a "watershed event" in the 36-year history of neutron star studies.
 Collision course. The first known pair of closely orbiting pulsars will merge in 85 million years.
CREDIT: JOHN ROWE ANIMATION |
The pulsars turned up after the 64-meter Parkes radio telescope in Australia spotted an energetic pulsar, whirling 44 times every second, orbiting a hidden object that they presumed was a nonpulsing neutron star. Deeper scrutiny revealed that the companion also pulses at a leisurely rate of once every 2.8 seconds. But jaws dropped when the discovery team announced that the slower pulsar swoops almost directly in front of the faster one as they orbit in tandem, eclipsing the fast pulsar for nearly 30 seconds each orbit.
There's more. Blasts of particles and radiation from the fast pulsar distort the slow pulsar's magnetic field, making its radio signal flicker and nearly die out. Astrophysicists were thrilled because the eclipses and the complex interactions yield the first direct probe of the blazing plasmas in which pulsars turn on their mysterious beacons. Theorists sifting the clues say the intense wind of charged gas streaming from the fast pulsar may be nearly a million times denser than expected.
Researchers also expect the pulsar pair to provide the most stringent examination yet of Einstein's general theory of relativity. If any deviations from Einstein's theory exist, they are most likely to arise within the superstrong gravity of a neutron star or black hole. Astrophysicists are gauging the pulsars' motions as they gradually spiral inward toward an inevitable crash 85 million years from now. These measures--aided by the ultraprecise clocks of the pulsars themselves--may reveal the density and distribution of matter within a neutron star for the first time.
Online Extras on Double Pulsars
| Papers and Articles |
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A. G. Lyne et al., "A Double-Pulsar System: A Rare Laboratory for Relativistic Gravity and Plasma Physics," Science 303, 1153 (2004)
M. A. McLaughlin et al., " The Double Pulsar System J0737-3039: Modulation of the Radio Emission from B by Radiation from A," astro-ph/0407265 (2004) [arXiv.org preprint server]
M. A. McLaughlin et al., " The Double Pulsar System J0737-3039: Modulation of A by B at Eclipse," astro-ph/0408297 (2004) [arXiv.org preprint server]
Maxim Lyutikov, " On the nature of eclipses in binary pulsar J0737-3039," astro-ph/0403076 (2004) [arXiv.org preprint server]
Jonathan Arons et al., " Probing Relativistic Winds: The case of PSRJ07370-3039 A & B," astro-ph/0404159 (2004) [arXiv.org preprint server]
R. Irion, "Double Pulsar Gives Astrophysicists Many-Faceted Thrills," Science 303, 153 (2004)
- E. P. J. van den Heuvel, " Double Pulsar Jackpot," Science 303, 1143 (2004)
- An Enhanced Perspective about the double pulsar discovery.
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| Interesting Web Sites |
- "First-Known Double Pulsar Opens up New Astrophysics"
- Information about the double pulsar discovery from the Jodrell Bank Observatory.
- Pulsar information resources
- Resources and links provided by the Pulsar Research Group at Jodrell Bank Observatory.
- Pulsar Education Page
- The Pulsar Group at the Australia Telescope National Facility provides an introduction to pulsars and a pulsar tutorial.
- Pulsars
- An introduction to pulsars from the Goddard Space Flight Center's Imagine the Universe.
- Pulsars
- Cambridge Physics provides an introduction to pulsars and a history of Jocelyn Bell and Antony Hewish's discovery of pulsars.
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Post By：2004/12/19 20:18:21
