Two types of glitches in a solid quark star model

• Published in: Monthly notices of the Royal Astronomical Society Vol. 443; no. 3; pp. 2705 - 2710
• Main Authors: Zhou, E. P., Lu, J. G., Tong, H., Xu, R. X.
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 21-09-2014
• Subjects: Accretion disks; Pulsars; Star & galaxy formation; X-ray astronomy; dense matter; pulsars: general; stars: magnetar; stars: neutron
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stu1370

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 (Δν/ν ∼ 10−6) but release negligible energy, whereas the large glitches of AXPs/SGRs (anomalous X-ray pulsars/soft gamma repeaters) 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.