UC
Santa Cruz: Astronomers
Bülent
Kiziltan and Stephen Thorsett of the University of California,
Santa Cruz, have come up with a more accurate way to peg
the ages of millisecond pulsars.The standard method for
estimating pulsar ages is known to yield unreliable results,
especially for the fast-spinning millisecond pulsars, says
Kiziltan."An accurate determination of pulsar ages is of
fundamental importance, because it has ramifications for
understanding the formation and evolution of pulsars, the
physics of neutron stars, and other areas," he adds.The
standard approach to determine the "characteristic" or
"spin-down" age of a pulsar is based on two parameters: the
period between pulses and the rate at which they slow down.
Kiziltan and Thorsett showed that this method may over- or
under-estimate the age of a pulsar by a factor of 10 when
applied to millisecond pulsars.To improve the accuracy of the
standard technique, they incorporated additional constraints
that arise from the spin-up process and physical limits on the
maximum spin period. "We modified the age calculations to be
consistent with these constraints and showed that this approach
can achieve estimates closer to the true age of the pulsar,"
Kiziltan says.By including in their model previously ignored
features such as the maximum possible rate of rotation and
subtle shifts in the observed radio frequency due to a pulsar's
motion across the sky, the team finds that some millisecond
pulsars are up to 10 times younger or 10 times older than
earlier estimates suggest.
