pulsar timing noise

Pulsar timing noise is slight irregularities in the arrival times of radiation from a pulsar due to irregularities in the pulsar's rotation which are believed to be caused by changes in the extent to which the pulsar's super-fluid core is connected to its surface. In searching for pulsar planets, it is important to discriminate between possible effects due to timing noise and the more regular changes in a pulsar's period that may indicate the presence of a planetary companion.