Missile Tracking Telescope Reveals Fate and Evolution of Young Crab Pulsar

A radio telescope once used to track ballistic missiles has now been employed by astronomers to find out a little bit more about our universe. Using this telescope, researchers have spied how a magnetic field structure and rotation of the young Crab pulsar evolves with time.

The Crab pulsar is a neutron star which formed in a massive cosmic explosion in 1054 AD. In fact, this explosion was so bright that people in both Europe and China spied the phenomenon in the daytime sky. These days, the pulsar rotates 30 times per second, emitting beams of radio waves that, like a lighthouse, produce flashes each time it rotates. Although it's only about 25 km across, it has the mass of nearly 1 million Earths.

In order to learn more about this pulsar, the researchers used the radio telescope to watch the Crab pulsar almost daily for 22 years. During this time, the pulsar has rotated 30 billion times. More specifically, the researchers examined the steady change of the flashes as the pulsar rotated. These flashes told the researchers about its very strong magnetic field and helped them learn about the otherwise-inaccessible interior of the star.

The flashes themselves come in pairs, and the new observations showed that the spacing of these pairs of pulses is increasing by .6 degrees per century. This is a surprisingly large rate of evolution and shows how the pulsar is slowing down rapidly over time.

"This pulsar is just 960 years old, so while 22 years gives only a small sample of its lifetime, it is a much larger fraction of a stellar lifetime than astronomers usually get to study," said Sir Francis Graham Smith, one of the researchers, in a news release.

The findings reveal a little bit more about the evolution of pulsars. More specifically, the study gives astronomers vital clues about how these cosmic lighthouses shine and explains a long-standing mystery about the way pulsars slow down over time. This, in turn, could inform future studies about these super dense bodies in our universe.

The findings are published in the journal Science.