SETI public: Fw: Published Paper Probes Pulsar Pair

From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Apr 28 2004 - 20:50:43 PDT

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    From: NASA Jet Propulsion Laboratory<mailto:info_at_jpl.nasa.gov>
    To: ljk4_at_msn.com<mailto:ljk4_at_msn.com>
    Sent: Wednesday, April 28, 2004 5:54 PM
    Subject: Published Paper Probes Pulsar Pair

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

    Jennifer Towell (514) 398-8585
    McGill University, Montreal

    News Release: 2004-114 April 28, 2004

    Published Paper Probes Pulsar Pair

    The only known gravitationally bound pair of pulsars -- extremely
    dense, spinning stars that beam radio waves -- may be pirouetting
    around each other in an intricate dance.

    "Pulsars are intriguing and puzzling objects. They pack as much mass
    as the Sun crammed into an object with a cross-sectional area about as
    large as Boston," said Fredrick Jenet of NASA's Jet Propulsion
    Laboratory, Pasadena, Calif. Jenet and Scott Ransom of McGill
    University, Montreal, Quebec, Canada, have developed a theoretical
    model to explain the behavior of this one-of-a-kind set of pulsars.

    "The physics of radio pulsar emission has eluded researchers for more
    than three decades," Jenet said. "This system may be the 'Rosetta
    stone' of radio pulsars, and this model is one step toward its
    translation."

    The research appears in the April 29 issue of the journal Nature.
    Jenet and Ransom studied the recently-discovered double pulsar system,
    in which two spinning pulsars orbit each other.

    The discovery of the two-star system, officially named PSR
    J0737-3039B, was announced in 2003 by a multinational team of
    researchers from Italy, Australia, the United Kingdom and the United
    States. Those researchers proposed that the duo contained one spinning
    pulsar and a neutron star. Later in 2003, scientists working at the
    Parkes Observatory in New South Wales, Australia, determined that both
    stars are actually pulsars. This discovery marked the first known
    example of a "binary," or double, pulsar system. The stars are
    referred to as A and B.

    Pulsars emit high-intensity radio radiation into a narrow beam. As the
    pulsar rotates, this beam moves in and out of our line of sight.
    Hence, we see periodic bursts of radio radiation. In this sense, a
    pulsar works like a lighthouse, in which the light may be on all the
    time, but it appears to blink on and off. Scientists were surprised to
    find that the B pulsar is on only at certain locations in its orbit.
    "It's as though something is turning B on and off," Jenet said.

    According to Jenet and Ransom, this "something" is closely related to
    the radio emission beam emanating from the A pulsar. They believe that
    B becomes bright when it is illuminated by emission from A. Jenet and
    Ransom used Einstein's Theory of General Relativity to predict the
    future evolution of this pulsar system. The theory implies that
    gravitational effects will change the emission pattern of A, which
    will then alter the exact orbital locations where B becomes bright.

    The double pulsar system is located about 2,000 light years, or 10
    million billion miles, from Earth. Jenet and Ransom based their
    research on observations made at the Green Bank Telescope in West
    Virginia.

    -end-


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