Planets Around Pulsars
One of the first discoveries of planets was made in1991 by Wolszczan and Frail using radio telescopes in Arecibo, Puerto Rico, and in Socorro, New Mexico.
They observed cyclic changes in the period of the pulsar PSR 1257+12 (a neutron star spinning once every 6.2 millisec).
The variations are caused by the motion of the neutron star as it is tugged by pull of 3 orbiting planets.
| Planet | Period (days) |
Mass (Earth=1) |
| A | 25 | 0.019 |
| B | 67 | 4.3 |
| C | 98 | 3.6 |
These planets must have formed after the supernova explosion that made the pulsar. Perhaps they formed from the debris of a companion star eroded by the energetic beams of the pulsar.