Pulsar slow glitches in a solid quark star model

TL;DR

This paper models slow glitches in pulsar B1822-09 using a solid quark star framework, explaining the phenomenon through shear stress buildup and superficial layer collapse, supported by numerical calculations.

Contribution

It introduces a novel solid quark star model for slow glitches, detailing the physical mechanism and providing parameter estimates consistent with observations.

Findings

Numerical simulations reproduce observed slow glitches.

Effective viscosity coefficient estimated at ~10^2 cm^2/s.

Initial superficial layer velocity around 10^{-10} cm/s.

Abstract

A series of five unusual slow glitches of the radio pulsar B1822-09 (PSR J1825-0935) were observed over the 1995-2005 interval. This phenomenon is understood in a solid quark star model, where the reasonable parameters for slow glitches are presented in the paper. It is proposed that, because of increasing shear stress as a pulsar spins down, a slow glitch may occur, beginning with a collapse of a superficial layer of the quark star. This layer of material turns equivalently to viscous fluid at first, the viscosity of which helps deplete the energy released from both the accumulated elastic energy and the gravitation potential. This performs then a process of slow glitch. Numerical calculations show that the observed slow glitches could be reproduced if the effective coefficient of viscosity is ~10^2 cm^{2}/s and the initial velocity of the superficial layer is order of 10^{-10} cm/s in the coordinate rotating frame of the star.