Anomalous Temporal Behaviour of NP 0532

Abstract

RECENT high-precision studies of the temporal behaviour of NP 0532 in the radio¹ and optical² bands have yielded conflicting values of the second derivative of the period and, consequently, the physical processes with which the temporal behaviour can be reconciled. It is the purpose of this communication to point out that a comparison of those two results with each other, and with other existing NP 0532 data, yields the result that the average second derivative over periods of time larger than a few months is inconsistent with that measured in either of the high-precision measurements. One possible reconciliation of this difficulty may be obtained by invoking discontinuous decreases in the period. We conclude that measured values of the second derivative may not necessarily give a reliable indication of the braking mechanism.