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 emission Some nucleides, e.g. Be-9, can be induced to eject a neutron by gamma radiation. Neutron emission usually happens from nuclei that are in an excited state, such as the excited O* produced from the beta decay of N. The neutron emission process itself is controlled by the nuclear force and therefore is extremely fast, sometimes referred to as "nearly instantaneous". This process allows unstable atoms to become more stable. The ejection of the neutron may be as a product of the movement of many nucleons, but it is ultimately mediated by the repulsive action of the nuclear force that exists