New theory may explain slowing of pulsar rotation

Ars Technica : Observations have shown that most pulsars’ periods of rotation are slowing down, but current models, which assume the slowdown is due to the emission of radiation, have failed to accurately predict the rate of that slowing. A new theory, presented by Wynn C. G. Ho and Nils Andersson, suggests that the inner and outer layers of a pulsar rotate at different speeds. Ho and Andersson’s model predicts that a pulsar’s core, which is believed to be a neutron superfluid mixed with a proton superconductor, is more superfluid than superconductor. The greater proportion of superfluid content allows the interior to continue spinning at a more constant rate. Because the pulsar then has two layers rotating at different rates, it experiences a braking effect that slows the rotation more than the emission of radiation does. More observations of pulsars are needed to evaluate the accuracy of the theory’s predictions. And until the exact nature of the pulsar’s interior can be determined, direct confirmation of the theory won’t be possible.