Artist's view of a neutron star.
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Definition

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Different models of composition of the interior of a neutron star.

The core of a supergiant star that collapses during a supernova explosion acquires such a density that protons and electrons can combine to form neutrons. The star that is formed thus becomes a sort of giant atomic nucleus composed mostly of neutrons, hence the name of this star.

Most of the stars between 8 and 60 solar masses end their lives as well, leaving behind a neutron star of about 1.4 solar mass.

Structure of a neutron star

A neutron star is about 10 kilometers radius and has an extraordinary density - a teaspoon of matter weighs hundreds of millions of tons. The structure of this star is actually complex and it is not clear what the exact composition of his heart is. Neutron stars are sometimes also pulsars when they emit periodic radio pulses in the direction of the Earth. Magnetars are neutron stars with a particularly intense magnetic field.

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the neighboring star of the Earth

Calvera -Earth’s Closest Neutron Star Discovered
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Calvera is at a distance of 250 to 1000 light-years away from us, in the constellation of Little Bear, but outside the galactic plane. Astronomers think it could be the remains of the explosion of a supernova, which would have been evicted. But one thing seems to be gained, it is that it is indeed the neutron star closest to us.

Its very bright X-ray radiation and its proximity make it a prime target for studying this type of star. Several research programs are already planned, using radio telescopes but also the Chandra satellite to determine if Calvera emits pulses in the X and radio domains.

Finally, astronomers think that Calvera could represent a type of isolated neutron stars now poorly known and little observed but present in dozens of copies in our galaxy, and that Swift is really the key to discover them .