October 28, 2007 - In 1054, Chinese and Arab astronomers noticed a new star shining brilliantly in the sky. This was one of the first recorded observations of a supernova, and the remnants of that explosion are what we now call the Crab Nebula.

The nebula still interests astronomers today, as in addition to its spectacular beauty, it's host to a pulsar with curious properties that may change drastically our understanding of the physics of pulsars.

A team led by Dr. Jean Eileck and Tim Hankins at New Mexico Tech looked at the Crab pulsar in the radio spectrum using the Very Large Array and Aricebo telescopes, and discovered to their surprise that the pulsar's radio emissions are much more complex than previously thought.

Their article, What makes the Crab pulsar shine?, appeared in the proceedings of the meeting Forty Years of Pulsars: Millisecond Pulsars, Magnetars and More.

The Crab pulsar – a rapidly spinning neutron star that emits radiation from its magnetic poles like a lighthouse – actually emits two different pulses; one is called the main pulse, and the other, which is about 160 degrees away in rotation from the main one, is called the interpulse.

They looked at individual pulses over very short periods of time to tease apart their properties, and found that the interpulse differs in three significant ways from the main pulse on certain radio frequencies: it produces light that is more polarized - the wavelengths of light are more aligned together - the interpulse lasts longer, and the radiation emitted is more dispersed.

http://www.universetoday.com/2007/10/23/the-peculiar-pulsar-in-the-crab-nebula/#more-11958