What is a Magnetar?
A magnetar is a neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious amounts of high-energy electromagnetic radiation, particularly X-rays and gamma-rays.Magnetars are somewhere around 20 kilometres in diameter. Despite this, they are substantially more massive than our Sun.
A magnetar is a type of supernova remnant; specifically, a neutron star with an extremely intense magnetic field. Magnetars underlie observed astronomical phenomena such as soft gamma repeaters and anomalous x-ray pulsars. Tensions in the magnetar’s crust periodically cause “starquakes” and release electromagnetic radiation in the form of x-rays, producing pulses about every ten seconds which can be observed by astronomers on Earth. At irregular and longer intervals, gamma rays are also released. Magnetars are created when a supergiant star runs out of nuclear fuel and collapses catastrophically as a supernova. For a magnetar to be produced, the star must have a fast rotational speed and magnetic field prior to the collapse. This happens in only about 1 out of 10 cases. Depending on the star’s mass, a neutron star or black hole is left over as the supernova remnant. If the supergiant star is rotating very quickly as it collapses, and it isn’t so massive, it collapses into a black hole,
In the August 27 section of the same “Magnetar” web page, there is an interesting story about how a new SGR was detected. Explain how and why the Earth’s ionosphere changes in response to a gamma-ray burst (this is one way Astronomers detected the outburst, by monitoring changes in the Earth’s ionosphere).
