What is the difference between pulsars and neutron stars?
A pulsar is a kind of neutron star: one that shows periodic pulsations. So all pulsars are neutron stars, but not every neutron star is a pulsar. Most neutron stars have strong magnetic fields, and as these stars rotate, this magnetic field rotates with them. That motion gives rise to a beam of radiation – like a flashlight – that points out from the magnetic poles. The rotation of the star then causes this beam to periodically sweep through our line of sight. Every time this happens, we see a brief pulse. Those pulses, which repeat at the exact rotation period of the neutron star, are what make it a pulsar.
How much radiation the star can produce this way depends on how fast it is spinning, and on how strong the magnetic field is. As the star ages, the pulses will disappear. It is still a neutron star, and we may still see it through other means, but it is no longer a pulsar. So what is the difference between a neutron star and a
pulsar? Basically, just how we look at them. Peter Bult is an astrophysicist at NASA’s Goddard Space Flight Center, Maryland