Their magnetic fields block light. A star has a parallax of 0.1 arc seconds. Charged particles ripped off the surface of a neutron star spiral around its magnetic field lines. This acceleration causes them to radiate. The surface of a neutron star pulsates, throwing off waves of radiation.
Pulsars radiate just like main-sequence stars.
Pulsars do not radiate, because not even light can escape their strong gravity. There is currently running water on the Martian surface,and we assume it was also present in the past. A high-mass star's core is already very hot, so it only needs to compress its core a little to burn helium . This statement is false. It is much harder for high-mass stars to burn helium.