Cassiopeia A Not Dead Yet |
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Written by spacetravel.org
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Wednesday, 22 June 2005 22:13 |
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 Cassiopeia A, the remnant of a star that died in a supernova explosion 325 years ago, has probably released at least one burst of energy as recently as 50 years ago. During an instrument test of NASAs Spitzer Space Telescope, an infrared echo was discovered coming from Cassiopeia A. As light waves from supernovae or erupting stars move outward, they heat up clumps of surrounding dust, causing them to glow in infrared light. The infrared echo from Cassiopeia A is the largest one ever seen, and the first discovered around a star that has been dead for a long time.
A supernova remnant, such as Cassiopeia A, typically consists of the core skeleton of a once massive star, known as a neutron star, and an outer shell of expelled material. There are several varieties of neutron stars, ranging from silent to intensively active. Stars that have recently died usually will continue to act up. Because of this, astronomers had wondered why the star which created Cassiopeia A seemed to be silent so soon after its death. The new infrared echo shows that the Cassiopeia A neutron star is active and may even be a magnetar. Magnetars have eruptive surfaces that emit huge amounts of high-energy gamma rays.
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