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Supernova 1987A, II

February 22, 2012

Astronomers have been hunting for a neutron star for 25 years, but they haven't been able to find it. They know that it was born 25 years ago tomorrow as seen from Earth. And they know just where it is. But no matter how hard they've looked, they haven't been able to find it.

The neutron star was born when a supergiant star exploded in a companion galaxy to the Milky Way. The blast is known as Supernova 1987A.

Astronomers know that the blast gave birth to a neutron star because they detected an outburst of the particles known as neutrinos shortly before the supernova itself became visible.

Theory says that as a supergiant star uses up the nuclear fuel in its core, the core collapses to form a neutron star or black hole. The collapse triggers the birth of enormous numbers of neutrinos, which race outward with a shockwave that blasts the star apart.

The outburst of neutrinos lasted a few seconds — long enough to indicate that the collapsing star formed a super-dense neutron star. A shorter outburst would have meant that the collapse formed a black hole, which would have prevented most of the neutrinos from escaping.

Even so, no telescope on Earth or in space has been able to see the neutron star. That could mean that it's just too quiet and faint to detect. Or it could mean that, soon after the blast, a lot of material fell back on the neutron star, causing it to collapse even more — forming a black hole.

More tomorrow.


Script by Damond Benningfield, Copyright 2011


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