What’s so ‘super’ about a supernova—a naturally occurring stellar explosion equivalent to the detonation of a few octillion nuclear warheads? Recent news indicates that this occurrence is nothing short of super and definitely far from ordinary. On January 9, 2008, the Burst Alert Telescope, a device built into NASA’s Swift satellite, recorded an exciting supernova observation seen by team leader Alicia Soderberg of Princeton University. The star SN 2008D exploded, creating a supernova 100 billion times brighter and 20 times larger than the size of the Sun.
Soderberg reveals that, “the probability of that happening is about one in 10,000. It was really exciting. We caught the whole thing on tape, basically.” Astronomers usually catch the after-effects of stellar explosions, but this is the first time that a star has been caught in the act. “For years we have dreamed of seeing a star just as it was exploding, but actually finding one is a once in a lifetime event,” says Soderberg.
Supernova SN 2008D lasted only seven minutes but during that time it illuminated the galaxy with blinding light. Researchers concluded that this star was most likely 20 times the size of the Sun and expanded at 70 per cent the speed of light. This occurrence strengthens many theorists’ current astrophysical models of supernovae which hypothesize that when a massive star burns all of its nuclear fuel, its iron core collapses under its own gravity causing an implosion. As a result, a forceful shockwave manifests, detonating the star and releasing numerous flashes of x-rays into interstellar space. “Seeing the shock break out in x-rays can give a direct view of the exploding star in the last minutes of its life and also provide a signpost to which astronomers can quickly point their telescopes to watch the explosion unfold,” reported Edo Berger of Princeton University.
This rare celestial phenomenon occurs approximately once every 50 years and is the ultimate outer space explosion. Supernovae have the potential to radiate the same amount of energy the sun emits in its lifetime, and emit a shockwave of gas and dust up to a tenth the speed of light into the abyss of interstellar space. And they don’t just put on a spectacular light show. Their explosions also generate elements heavier than iron which ultimately create other stars and planets.
“Novae are ordinary stars that increase in brightness, while supernovae are even brighter. They are explosions of white stars that can be eight times the mass of the sun,” says Chris Matzner, Assistant Professor in the Astronomy Department at the University of Toronto. He distinguishes between the two main types of supernovae: type I and type II. Generally speaking, type I supernovae result from white dwarf stars rich in carbon and oxygen. In most situations, white dwarf stars accumulate a large amount of matter, becoming increasingly dense and, as a result, the carbon and oxygen fuse causing the star’s explosion. Type II supernovae usually occur when a considerably large star is near death. When its nuclear fuel is depleted, it no longer has a supply of energy to support it. The star’s iron core then collapses giving rise to a supernova.
Ultimately, the really super aspect of supernovae may be their ability to teach us about the cosmos. As Soderberg puts it, “This newly born supernova is going to be the Rosetta stone of supernova studies for years to come.”
