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 ev
ery 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.
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 ev
ery 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.
A type of variable star that changes its brightness by changing its volume through expansion and contraction. Classical pulsating stars, including Cepheids, RR Lyrae, and Delta Scuti variables, are lo
cated in a quite narrow almost vertical region in the H-R diagram, known as instability strip.
A rapid fluctuation of the geomagnetic field having periods from a fraction of a second to tens of minutes and lasting from minutes to hours. There are two main patterns: Pc (a continuous, almost sinu
soidal pattern), and Pi (an irregular pattern). Pulsations occur at magnetically quiet as well as disturbed times.
The way in which pulsations occur in a star due to the fact that stars act as resonant cavities, as studied in asteroseismology. A star may pulsate either with approximately spherical symmetry (radial
pulsation), or as a series of waves running across the surface (non-radial pulsation). Pulsation may occur in a single mode or in multiple modes, depending on the type of star. Three different modes of pulsations have been detected through the helioseismology of the Sun: p mode, g mode, and f mode, generated by acoustic, gravity, and surface gravity waves respectively.