1.5 The Observational Features
33
Fig. 1.4 Glitch of Vela
Pulsar from 1968 to 1980
more than 10 glitches from the Vela Pulsar had again been observed from 1971 to
1994, as shown in Fig. 1.4. In general case, the periodic change rate of the Vela Pulsar
is about 3.53 × 10
–17 s/s, far less than the rate during the glitch occurring, and the
change direction between the two rates is just contrary. In addition, seven glitches
from the Crab Pulsars had also been observed from 1969 to 1996 and the large glitch
got to 10
–8 orders, and in November 2017, the Crab pulsar suffered from the largest
glitch in the observed records, with 10
–7 orders. And At present, the glitches from
tens of pulsars have been observed. The glitches occur at intervals of a few years
for the young pulsars, and the older are the pulsars, the longer the intervals of the
glitches, so that the majority of pulsars have not been observed to glitches even during
several decades of observation.
The mechanism of the glitch is one of the research hotspots in the field of radio
astronomy. One view is that the glitches result from the “star-quakes” of neutron
stars. The centrifugal force produced by rapidly rotating neutron star deforms the
crust of neutron star and its equator partly rises; with the rotating power gradually
transformed into radiant energy, the rotating rate of the neutron star slows down
and the centrifugal force gradually decreases; and thus, a part of the equator of the
star’s crust will fracture and collapse with the centrifugal force decreasing, so that
the matter inside neutron star redistributes and the rotating rate increases. It is shown
from the calculated results that if the crust of neutron star collapses to 1 mm, the
glitch will occur. The star-quake is not only “crust-quake” occurring on the surface of
neutron star, but also may be “core-quake” occurring in the solid core. The structures
and characteristics inside neutron stars can be understood by the star-quakes. Hence,
studies on the glitches and their recovering processions become a kind of effective
probes to explore interior compositions of the neutron stars. Although it can be
interpreted by the star-quake model that the glitches occur randomly and irregularly,
33
Fig. 1.4 Glitch of Vela
Pulsar from 1968 to 1980
more than 10 glitches from the Vela Pulsar had again been observed from 1971 to
1994, as shown in Fig. 1.4. In general case, the periodic change rate of the Vela Pulsar
is about 3.53 × 10
–17 s/s, far less than the rate during the glitch occurring, and the
change direction between the two rates is just contrary. In addition, seven glitches
from the Crab Pulsars had also been observed from 1969 to 1996 and the large glitch
got to 10
–8 orders, and in November 2017, the Crab pulsar suffered from the largest
glitch in the observed records, with 10
–7 orders. And At present, the glitches from
tens of pulsars have been observed. The glitches occur at intervals of a few years
for the young pulsars, and the older are the pulsars, the longer the intervals of the
glitches, so that the majority of pulsars have not been observed to glitches even during
several decades of observation.
The mechanism of the glitch is one of the research hotspots in the field of radio
astronomy. One view is that the glitches result from the “star-quakes” of neutron
stars. The centrifugal force produced by rapidly rotating neutron star deforms the
crust of neutron star and its equator partly rises; with the rotating power gradually
transformed into radiant energy, the rotating rate of the neutron star slows down
and the centrifugal force gradually decreases; and thus, a part of the equator of the
star’s crust will fracture and collapse with the centrifugal force decreasing, so that
the matter inside neutron star redistributes and the rotating rate increases. It is shown
from the calculated results that if the crust of neutron star collapses to 1 mm, the
glitch will occur. The star-quake is not only “crust-quake” occurring on the surface of
neutron star, but also may be “core-quake” occurring in the solid core. The structures
and characteristics inside neutron stars can be understood by the star-quakes. Hence,
studies on the glitches and their recovering processions become a kind of effective
probes to explore interior compositions of the neutron stars. Although it can be
interpreted by the star-quake model that the glitches occur randomly and irregularly,