![Pulsar. Astronomia y cosmos.jpg](https://steemitimages.com/DQmWaBTtdge1nhfXGyeZA3N2tQh3YMTnwbB4k2TnTwnYweT/Pulsar.%20Astronomia%20y%20cosmos.jpg)

A pulsar (from the English acronym of Pulsing star, which means "star that emits very intense radiation at short and regular intervals" 1) is a neutron star that emits periodic radiation. Pulsars have an intense magnetic field that induces the emission of these pulses of electromagnetic radiation at regular intervals related to the period of rotation of the object.

Neutron stars can rotate on themselves up to several hundred times per second; A point on its surface can be moving at speeds of up to 70 000 km/s. In fact, the neutron stars that spin so quickly expand in their equator because of this dizzying speed. This also implies that these stars have a size of a few thousand meters, between 10 and 20 kilometers, because the centrifugal force generated at this speed is enormous and only the powerful gravitational field of one of these stars (given its enormous density) is capable To avoid seams. 2 3

The combined effect of the enormous density of these stars with their intense magnetic field (generated by the protons and electrons of the surface revolving around the center at such velocities) causes the particles that approach the star from the Exterior (e.g., gas molecules or interstellar dust), accelerate at extreme speeds and make cerradísimas spirals towards the star's magnetic poles. Therefore, the magnetic poles of a neutron star are very intense places of activity. They emit radiation jets in the range of the radius, X-rays or gamma rays, as if they were very intense and very collimated electromagnetic radiation cannons.

For reasons not yet very well understood, the magnetic poles of many neutron stars are not on the axis of rotation. The result is that the "radiation cannons" of the magnetic poles do not always point in the same direction, but rotate with the star.

It is possible then that, looking at a certain point in the firmament, we receive a "jet" of X-rays for an instant. The jet appears when the star's magnetic pole looks towards the earth, stops pointing a thousandth of a second later due to the rotation, and appears again when the same pole re-points to the Earth. What we perceive then from that point in the sky are pulses of radiation with a very precise period, which are repeated over and over again (what is known as the ' Lighthouse effect ') when the jet is oriented towards our planet. Therefore, this type of neutron stars ' pulsating ' are called pulsars (pulsing star, ' pulsating star ', although this denomination is applied with more property to another group of variable stars). If the star is properly oriented, we can detect it and analyze its rotation speed. The period of the pulsation of these objects logically increases when their speed of rotation decreases. Despite this, some pulsars with extremely constant periods have been used to calibrate precision clocks.

![Ilustración-de-un-púlsar-800x416.jpg](https://steemitimages.com/DQmXvNGmRvMU31JvpXUgiKNbHXftRZgrCSY9EeiUBEzRuSV/Ilustraci%C3%B3n-de-un-p%C3%BAlsar-800x416.jpg)

In the first group of extrasolar planets discovered to orbit a pulsar, the PSR B1257 + 12, whose period is 6.22 ms (milliseconds). The small variations of its emission period in the radio were used to detect a periodic oscillation dusting with a maximum amplitude around 0.7 ms. The Radioastronomers Aleksander Wolszczan and Dale A. Frail interpreted these observations as caused by a group of three planets in nearly circular orbits at 0.2, 0.36 and 0.47 UA of the central Pulsar and with masses of 0.02, 4.3 and 3.9 terrestrial masses respectively.