Orion1
Aug7-04, 06:09 PM
When in a supernova a star collapses to a neutron star, its magnetic field increases dramatically in strength. Duncan and Thompson calculated that the magnetic field of a neutron star, normally an already enormous 10^12 tesla could under certain circumstances grow even larger, to about 10^15 tesla. Such a highly magnetic neutron star is called a magnetar.
In the outer layers of a magnetar, which consist of a plasma of heavy elements (mostly iron), this causes tension which leads to 'starquakes'. These seismic vibrations are extremely energetic, and result in a burst of X-ray and gamma ray radiation. To astronomers, such an object is known as a soft gamma repeater.
It is estimated that about 1 in 10 supernova explosions results in a magnetar rather than a more standard neutron star or pulsar.
The energy of these explosions slows the rotation (causing magnetars to rotate much more slowly than other neutron stars of a similar age) and lessens the electric field, and after only about 10,000 years the starquakes are over.
Reference:
http://www.wordiq.com/definition/Magnetar
http://science.nasa.gov/newhome/headlines/mag_pix/TV-graphics/xsection.tnl.jpg
http://science.nasa.gov/newhome/headlines/mag_pix/TV-graphics/xsection.jpg
http://science.nasa.gov/newhome/headlines/ast20may98_1.htm
http://science.nasa.gov/newhome/headlines/ast29sep98_1.htm
In the outer layers of a magnetar, which consist of a plasma of heavy elements (mostly iron), this causes tension which leads to 'starquakes'. These seismic vibrations are extremely energetic, and result in a burst of X-ray and gamma ray radiation. To astronomers, such an object is known as a soft gamma repeater.
It is estimated that about 1 in 10 supernova explosions results in a magnetar rather than a more standard neutron star or pulsar.
The energy of these explosions slows the rotation (causing magnetars to rotate much more slowly than other neutron stars of a similar age) and lessens the electric field, and after only about 10,000 years the starquakes are over.
Reference:
http://www.wordiq.com/definition/Magnetar
http://science.nasa.gov/newhome/headlines/mag_pix/TV-graphics/xsection.tnl.jpg
http://science.nasa.gov/newhome/headlines/mag_pix/TV-graphics/xsection.jpg
http://science.nasa.gov/newhome/headlines/ast20may98_1.htm
http://science.nasa.gov/newhome/headlines/ast29sep98_1.htm