Thursday, July 7, 2011

Gamma ray flares in binary star are a mystery, 07.07.11

Image credit: NASA.
Something very odd has happened 8,000 light years away in the southern constellation Crux. A binary star system has emitted strange gamma ray flares as the small pulsar star of the pair approached and passed through its closest point in orbit around the large Be-class star.
The Be-class star, designated LS 2883, is surrounded by a disc of gas. As the small neutron star, the pulsar B1259-63, approaches, it emits some gamma rays as it grazes through either side of the disc every 3.4 years.
On January 20 and February 21 of this year, however, when the pulsar approached the larger star, a strange series of powerful gamma ray flares occurred, which was highly out of character. A thorough barrage of scans and studies revealed no anomalies in the stars; no foreign objects, no strange chemical reactions, nothing that would elicit flares like those.
Since the two stars pass by each other that closely only every 3.4 years, it is going to be a while before scientists get another chance to study it again. it is believed that as the pulsar passes thru the disk of gas and dust, that the pulsars powerful magnetic field is accelerating captured electrons to very high energies causing these weird month-long gamma ray displays. It is truly a case where astronomers are finding more and more strange objects or events that can cause a gamma ray burst.

 Credit: NASA.

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