A → pulsar of abnormally low magnetic field and short period.
The short period suggests that the pulasr is young, while the low field suggests a
very old pulsar. According to theoretical models, a pulsar at some point in its evolution
stops functioning as a pulsar. If it resides in a binary system
(→ binary pulsar), its magnetic field decays in the interval
when the companion evolves and fills its → Roche lobe.
The dead pulsar is eventually spun up to life when
→ mass transfer from the companion begins.
The pulsar gains → angular momentum from the infalling
gas and increases its spin rate as more gas falls onto it.
→ Millisecond pulsars that spin hundreds of times
per second are thought to be the result of such a transfer
(see, e.g., G. Srinivasan, 2010, New Astronomy Reviews 54, 93, and references therein).
See also: → recycle; → pulsar.