|“Recycling” observed in space|
An international team of researchers, including CRAQ members from McGill Anne Archibald and and her supervisor Vicky Kaspi, observed for the first time the evidence of “cosmic recycling”. Using the Green Bank radio-telescope, located in West-Virginia, they monitored the transformation of an ordinary pulsar, condemned to slow-down and to become invisible, into a fast-rotating pulsar, which life expectancy is quasi-infinite.
Pulsars are tiny rotating high-density stars made of neutrons. They are created at the end of the life of a very massive star, during the explosion called Supernova. Most of pulsars are slowly rotating (about 10 times per second) and slow down on timescales of millions of years before becoming extinguished. Pr. Vicky Kaspi explains that for a fraction of them, the story does not end that way:
"(...) some of the oldest one are being recycled into millisecond pulsars. They end up rotating very rapidly and can emit an eternal radiation".
Anne Archibald adds: "The study allowed us to discover a large number of pulsars but this one is really special. It is a pulsar recently recycled, just out of the recycling factory".
This study could shed light on the predicted theory that millisecond pulsars are created in binary systems (system of 2 stars), which allow the pulsar to keep its rotation speed thanks to its companion: "Imagine a tennis ball floating in a filled bathtub. As you remove the plug, the water starts forming a vortex around the ball and makes it rotate faster than when it was simply floating”, explains Anne Archibald.
The discovery has been published on May 21st 2009 in the prestigious journal Science http://www.sciencemag.org/cgi/content/abstract/1172740v1
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