Many pulsars radiate radio frequency or other radiation in a periodic manner
and are bound to a companion star in what is known as a binary pulsar system.
In \(2004,\) a double pulsar system, PSR J0737-3039A and J0737-3039B, was
discovered by astronomers at the Jodrell Bank Observatory in the United
Kingdom. In this system, both stars are pulsars. The pulsar with the faster
rotation period rotates once every \(0.023 \mathrm{~s}\), while the other pulsar
has a rotation period of \(2.8 \mathrm{~s}\). The faster pulsar has a mass 1.337
times that of the Sun, while the slower pulsar has a mass 1.250 times that of
the Sun.
a) If each pulsar has a radius of \(20.0 \mathrm{~km}\), express the ratio of
their rotational kinetic energies. Consider each star to be a uniform sphere
with a fixed rotation period.
b) The orbits of the two pulsars about their common center of mass are rather
eccentric (highly squashed ellipses), but an estimate of their average
translational kinetic energy can be obtained by treating each orbit as
circular with a radius equal to the mean distance from the system's center of
mass. This radius is equal to \(4.23 \cdot 10^{8} \mathrm{~m}\) for the larger
star, and \(4.54 \cdot 10^{8} \mathrm{~m}\) for the smaller star. If the orbital
period is \(2.4 \mathrm{~h},\) calculate the ratio of rotational to
translational kinetic energies for each star.