A rotating → neutron star that emits a radio
→ beam that is centered on the
→ magnetic axis
of the neutron star. As the magnetic axis and hence the beam are inclined to the
→ rotation axis, a
→ pulse is seen every time the → rotation
brings the → magnetic pole
region of the neutron star into view. In this way the pulsar
acts much as a light house does, sweeping a beam of radiation through space.
The pulse or spin periods range from 1.4
milliseconds to 8.5 seconds. As neutron stars concentrate an average of 1.4
→ solar masses on a diameter of only 20 km, pulsars are
exceedingly → dense and → compact,
representing the densest matter in the observable Universe. The pulsar radiation,
chiefly emitted in → radio
frequencies (0.1-1 GHz), is highly
→ polarized. The exact mechanism by which a
pulsar radiates is still a matter of vigorous investigation.
Simply put, an enormous electric field is induced by the rotation of a
magnetized neutron star. The force of this field
exceeds gravity by ten to twelve orders of magnitudes.
Charged particles are whereby pulled out from the stellar surface
resulting in a dense, magnetized plasma that surrounds the pulsar
(→ magnetosphere). The charged particles flow out
of the magnetic → polar caps of the neutron star, following
the open
magnetic field lines. The acceleration of the charged particles
along the curved magnetic field lines will cause them to radiate
(see, e.g., M. Kramer, 2010, astro-ph/1008.5032).
See also:
→ accreting neutron star,
→ anomalous X-ray pulsar,
→ binary pulsar,
→ black-widow pulsar,
→ Crab pulsar,
→ double pulsar,
→ Hulse-Taylor pulsar,
→ isolated neutron star (INS),
→ millisecond pulsar,
→ neutron star,
→ nulling fraction,
→ nulling pulsar,
→ optical pulsar,
→ pulsar glitch,
→ pulsar magnetosphere,
→ pulsar nulling,
→ pulsar planet,
→ pulsar wind nebula,
→ radio pulsar,
→ recycled pulsar,
→ rotation-powered pulsar (RPP),
→ Vela pulsar,
→ X-ray Dim Isolated Neutron Star (XDINS),
→ X-ray pulsar.
Etymology (EN): Pulsar, from puls(e) or puls(ing) + (st)ar.
Etymology (PE): Tapâr, from tap, → pulse, + (set)âr(é),
from setâré, → star.
