Deciphering Accretion-Driven Starquakes in Recycled Millisecond Pulsars using Gravitational Waves

Abstract

Recycled millisecond pulsars are susceptible to starquakes as they are continuously accreting matter from their binary companion. A starquake happens when the rotational frequency of the star crosses its breaking frequency. In this study, we perform a model analysis of an accreting neutron star suffering a starquake. We analyze two models: a spherical star with accreting mountains and a deformed star with accreting mountains. We find that as the star crosses the breaking frequency and suffers a starquake there is a sudden change in the continuous gravitational wave signal arriving from them. It is interesting to note that the amplitude of the gravitational wave signals increases suddenly for the spherical star. In contrast, for the deformed star, the amplitude of the continuous gravitational wave signal decreases suddenly. This sudden change in the continuous gravitational wave signal in recycled millisecond pulsars can be a unique signature for such pulsars undergoing a starquake.