Neutron Stars

Comparison of our sun and neutron star.

A tablespoon of neutron star would weight about one million tons.

  • mainly made up of neutrons, neutron stars are incredibly small, super-dense stars with a solid crust made of iron and similar elements.
  • although neutron stars weight as much as the sun, they are just 10 miles across on average.
  • neutrons stars form from the central core of a star that had died in a supernova explosion.

Neutron star found at supernova’s centre.

  • to produce a neutron star, a star must be more than 1.4 times as massive as a medium-sized star, such as the Sun – this is the Chandrasekhar limit.
  • a star more than three times as massive as the Sun would collapse beyond a neutron star to form a black hole – this is called the Oppenheimer-Volkoff limit.
  • the first evidence of neutron stars came when pulsars were discovered in the 1960’s.
  • the X-rays come from nearby stars as material is squeezed on to their surfaces by their gravity. (See below)

Some stars giving out X-rays, such as Hercules X-1, are neutron stars.

  • neutron stars have very powerful magnetic fields, billions of times stronger than the Earth’s, which stretch the atoms out into frizzy ‘whiskers’ on the star’s surface.

The most powerful magnets in the Universe are collapsed star.

The composition of their cores is unknown,
but they may consist of a neutron superfluid or some unknown state of matter.

  • neutron stars pack an extremely strong gravitational pull, much greater than Earth’s.
  • this gravitational strength is particularly impressive because of the stars’ small size.

Back to  Stars and Galaxies  page / next to  Pulsars  page.

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