The Vela pulsar jet


It is predicted that supernovae triggered by stars that do not have enough mass for their cores to form black holes will result in neutron stars.

Neutron stars are small (about 20km across), rotate rapidly and are incredibly dense. They are mostly made of neutrons that formed as electrons combined with protons in the atomic nuclei of the dying stars' collapsing cores. Their powerful magnetic fields lead to radio pulses that can be detected on the Earth each time they rotate. These objects are known as pulsars when the pulses can be detected on the Earth.

Image: The Vela pulsar jet (credit: NASA/CXC/PSU/G.Pavlov et al.)

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The Vela pulsar jet


Pulsars send signals across the Universe.

About Pulsars

A pulsar (short for pulsating radio star) is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth, much the way a lighthouse can only be seen when the light is pointed in the direction of an observer, and is responsible for the pulsed appearance of emission. Neutron stars are very dense, and have short, regular rotational periods. This produces a very precise interval between pulses that range roughly from milliseconds to seconds for an individual pulsar. Pulsars are believed to be one of the candidates of high and ultra-high energy astroparticles (see also Centrifugal mechanism of acceleration).

The precise periods of pulsars make them useful tools. Observations of a pulsar in a binary neutron star system were used to indirectly confirm the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12. Certain types of pulsars rival atomic clocks in their accuracy in keeping time.

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