Radio-quiet neutron star Radio-quiet neutron star A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly x-rays and gamma rays. Most detected neutron stars are pulsars, and emit radio-frequency electromagnetic radiation. About 700 radio pulsars are listed in the Princeton catalog, and all but one emit radio waves at the 400 MHz and 1400 MHz frequencies. That exception is Geminga, which is radio quiet at frequencies above 100 MHz, but is a strong emitter of X-rays and gamma rays. In all,
Neutron star momentum; like spinning ice skaters pulling in their arms, the slow rotation of the original star's core speeds up as it shrinks. A newborn neutron star can rotate many times a second. Over time, neutron stars slow, as their rotating magnetic fields in effect radiate energy associated with the rotation; older neutron stars may take several seconds for each revolution. This is called "spin down". The rate at which a neutron star slows its rotation is usually constant and very small. The periodic time ("P") is the rotational period, the time for one rotation of a neutron star. The spin-down