Monday, December 8, 2008

Neutron Star

A neutron star is a type of remnant that can result from the gravitational collapse of a massive star during a Type II supernova event. A neutron star is about 20 km in diameter and has the mass of about 1.4 times that of our Sun. This means that a neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons. Because of its small size and high density, a neutron star possesses a surface gravitational field about 2 x 1011 times that of Earth. Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth.

As the core of a massive star is compressed during a supernova, collapsing into a neutron star, it retains most of its angular momentum. Since it has only a tiny fraction of its parent's radius, a neutron star is formed with very high rotation speed, and then gradually slows down. The temperature inside a newly formed Neutron star is from 100 thousand million to a million million Kelvin. However, the huge number of neutrinos it emits carries away so much energy that the temperature falls within a few years to only one million Kelvin.