Star morphs from radio to X-ray pulsar and back again
http://www.astronomy.com/news/2013/09/star-morphs-from-radio-to-x-ray-pulsar-and-back-again

This star’s behavior appears to be fueled by a companion star and may give new insights into the birth of millisecond pulsars.

Astronomers have uncovered the strange case of a neutron star with the peculiar ability to transform from a radio pulsar into an X-ray pulsar and back again. This star’s capricious behavior appears to be fueled by a nearby companion star and may give new insights into the birth of millisecond pulsars.

“What we’re seeing is a star that is the cosmic equivalent of ‘Dr. Jekyll and Mr. Hyde,’ with the ability to change from one form to its more intense counterpart with startling speed,” said Scott Ransom from the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia. “Though we have known that X-ray binaries — some of which are observed as X-ray pulsars — can evolve over millions of years to become rapidly spinning radio pulsars, we were surprised to find one that seemed to swing so quickly between the two.”

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