Quarks and Compact Stars (QCS)
Oct. 20-22, 2014, KIAA at Peking University, Beijing - P. R. China

Two types of glitches in a solid quark star model

Jiguang Lu

Department of Astronomy, School of Physics, Peking University, Beijing 100871, P. R. China

Abstract: Glitch (sudden spin-up) is a common phenomenon in pulsar observations. However, the physical mechanism of glitch is still a matter of debate because it depends on the puzzle of pulsar's inner structure, i.e. the equation of state of dense matter. Some pulsars (e.g. Vela like) show large glitches but release negligible energy, whereas the large glitches of AXPs/SGRs are usually (but not always) accompanied with detectable energy releases manifesting as X-ray bursts or outbursts.We try to understand this aspect of glitches in a starquake model of solid quark stars. There are two kinds of glitches in this scenario: bulk-invariable (type I) and bulk-variable (type II) ones. The total stellar volume changes (and then energy releases) significantly for the latter but not for the former. Therefore, glitches accompanied with X-ray bursts (e.g. that of AXP/SGRs) could originate from type II starquakes induced probably by accretion, while the others without evident energy release (e.g. that of Vela pulsar) would be the result of type I starquakes due to, simply, a change of stellar ellipticity.