'Stars Can Die Twice'

It has traditionally been thought that a star dies either by exploding as a supernova to become a neutron star, or by becoming a white dwarf. A supernova refers to a phenomenon in which an old star emits a large amount of energy upon explosion, while a white dwarf is a celestial body that is formed as sun-scale stars gradually die.

However, it has recently been discovered that a star can die by exploding twice. An international group of researchers including Professor IM Myungshin of SNU's Department of Physics and Astronomy has analyzed the gamma ray burst which was observed on December 25 last year, to reach this conclusion.

A gamma ray burst is a phenomenon in which a star explodes with a huge amount of gamma light, and it usually occurs when a star dies. Such a burst has been observed many times, but the duration of light emission was usually only several seconds or minutes. A gamma ray is a type of light invisible to the naked eye, like an X-ray. The gamma ray burst that this group of researchers observed happened 4.3 billion light years away from the earth.
Last year on Christmas, the US's satellite 'Swift' observed the burst first. Subsequently, the National Aeronautics and Space Administration (NASA) named it 'GRB 101225A'.

Soon after the news of this explosion, astronomers around the world started to capture and analyze X-rays and infrared rays coming from the explosion site.Korean researchers used an astronomical camera called CQUEAN installed at the McDonald Observatory located in Texas in the US. Their research results were published in the December 1 issue of the renowned academic journal Nature.

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