Some astrophysics vocabulary

Here are some words to remember:

  • White dwarf: This is a star that is held up by the pressure of its electrons. Due to the Pauli exclusion principle, the electrons can not all have zero momentum, and must therefore exert pressure.

  • Chandrasekhar limit: Stars with masses above this limit will overcome the electron pressure and collapse. The limit is 1.4 solar masses.

  • Supernova: Stars which are significantly above the Chandrasekhar limit may bounce just after they collapse. This blows the surface of the star into space and releases an enormous amount, ~ 1046 J, of energy.

  • Neutron star: This is a star which has collapsed, but is held up by the pressure of compressing the neutrons to nuclear matter densities. The protons and electrons in a normal star have converted via the reaction .

  • Black hole: This is formed by a star which is so massive that it collapses to a singularity. Even light is trapped in the interior.

Examples     Cosmo/Astro index