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Supernovae
by Jeanette Cain
Supernovae are rare and most are hidden by interstellar dust. Astronomers have found many in other galaxies, but the last time one was seen in the Milky Way was in 1604. The largest and heaviest of these stars will end their life in a gigantic explosion called a supernova. It breaks out into space and it will out shine an entire galaxy for several days. The glowing remains of the stars from hundreds and thousands of years can still be found and observed.
One of the stellar remains of a supernova is called Tycho Brahe, since Brahe studied it in great detail. It exploded in 1572 in Cassiopeia. About 11,000 years ago a supernova exploded, known as Vela. Its center is approximately 1,500 light years from the Sun. Vela's material collided with space gas as it expanded at thousands of kilometers a second. The collision caused heat, which made it glow. Hydrogen bears the color of red and oxygen has the color of blue. Vela's remnants can be observed through X-ray telescopes.
Supernovae can be found by astronomers using special telescopes, whereas, previous discoveries were only through accidental means. With the use of automatic telescopes and computers, scientists can search hundreds of far away galaxies during one night. Others playing an important role in this process are amateur astronomers. From eyes and memory, to the use of electronic cameras, or traditional photography, the amateur helps astronomers in many discoveries. The first amateur to discover a supernova was in 1957, but amateur's are credited with over 130 more discoveries.
On February 23, 1987, in a small satellite galaxy of the Milky Way-Large Magellanic Cloud, the Earth's skies showed the brightest supernova seen in over four centuries. Its brightness reached 2.8 magnitude over an 85 day period. A burst of neutrinos were found from the core's collapse three hours before it began to brighten. The supernova's name is Supernova 1987A. It was the first to be studied with modern day instruments.
Exploding supergiants are Type II supernovae. Even more powerful are the Type Ia supernova. The small white dwarf star will pull gas from the larger companion star. Its mass may increase to the point of losing the ability to support itself, which results in its self-destruction. Type Ia supernovae are consistent in always reaching the same brightness.
Source:
1. Editors. Secrets of the Universe. International Master Publishing: US. 1999
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