Pulsar

A pulsar (pulsating star, on the model of quasar) is a highly magnetized rotating <a href="/facts/Neutron_star/4enfoxBA">neutron star</a> that emits beams of <a href="/facts/Electromagnetic_radiation/Ynx7ujCW">electromagnetic radiation</a> out of its <a href="/facts/Poles_of_astronomical_bodies/HEz90QFn">magnetic poles</a>. This radiation can be observed only when a beam of emission is pointing toward Earth (similar to the way a <a href="/facts/Lighthouse/HAwW4RFW">lighthouse</a> can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission. Neutron stars are very <a href="/facts/Density/92p6hh9I">dense</a> and have short, regular rotational <a href="/facts/Period_(physics)/QUSbPaW8">periods</a>. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of <a href="/facts/Ultra-high-energy_cosmic_ray/DqeCybD9">ultra-high-energy cosmic rays</a> (see also <a href="/facts/Centrifugal_mechanism_of_acceleration/zR7C1lHU">centrifugal mechanism of acceleration</a>.)
Pulsars’ highly regular pulses make them very useful tools for astronomers. For example, observations of a pulsar in a <a href="/facts/PSR_B1913%2B16/GMTAbnBj">binary neutron star system</a> were used to indirectly confirm the existence of <a href="/facts/Gravitational_wave/4XWN3NtG">gravitational radiation</a>. The first <a href="/facts/Exoplanet/zjfmqfUf">extrasolar planets</a> were discovered in 1992 around a pulsar, specifically <a href="/facts/PSR_B1257%2B12/HzcsebRf">PSR B1257+12</a>. In 1983, <a href="/facts/Millisecond_pulsar/oVK1zXrx">certain types of pulsars</a> were detected that, at that time, exceeded the accuracy of <a href="/facts/Atomic_clock/MF8nsXDR">atomic clocks</a> in <a href="/facts/Pulsar_clock/VSjlwvrL">keeping time</a>.

Pulsar open-in-new

Pulsar