Neutron stars usually turn very fast, taking from 0.001 second up to 30 seconds to turn.
They come in different types. One kind is the pulsar which spins and sends a beam of radio waves (like a lighthouse in space). When this beam moves past Earth, it shows up as a pulse (like the light from a lighthouse is seen as a flash on the horizon). This 'pulse' is why they are called pulsars.
[change] Starting as a supernova
All other stars that go supernova become neutron stars.
[change] Starting as a white dwarf
A white dwarf whose mass is nearly 1.4 times the mass of the Sun will sometimes get bigger (but no one knows why). When this happens, it will collapse into a neutron star.
Neutron stars have the same properties:
Neutron stars rotate much faster than other stars.
Neutron stars are very dense. They are much denser than anything we find naturally on the Earth.
To imagine how dense a neutron star is, take all of the mass of our sun (which has a diameter of 1,392,000 kilometres (865,000 mi)) and pushing it down into a size that would fit into a ball with a 19 kilometres (12 mi) diameter.
[change] Magnetic Field
Neutron stars have very strong magnetic fields. They are some of the strongest magnetic fields that occur naturally.
All stars have a magnetic field. When a star collapses, it becomes smaller. This means that the magnetism is pushed into a smaller area, which means that the magnetic field is stronger nearer the star.