Sun

Sun | nearest neghbour | spectral type | other stars

Sun

The Sun is our very own star, at or very near the centre of the Solar System. Some of the time it's not quite at the centre because Jupiter is so massive the centre of mass of the two bodies (known as the barycentre) works out to be a bit above the Sun's surface. When the other planets are on the same side of the Sun that Jupiter is on, the Solar System's barycentre ends up outside the Sun. This was the case, for example, from 1978 to 1988, 1993 to 2004, and will be so from 2017 for about ten years.

The Sun contains 99.86% of the mass of the solar system but only 2% of the angular momentum. This is problematic for theories of formation of the Solar System.

98% of the mass of the Sun is hydrogen and herium.

The Sun has a spectral type of G2V, meaning it has a surface temperature of 5,500 K and that its spectrum contains spectral lines of neutral metals, and is a main sequence star. More information on spectral types is on the Spectral Types page.

Nearest neighbour

The nearest star system to the Sun is Alpha Centauri. It is a triple star system, with the individual stars designated A, B and C in order of brightness (and mass). More information is on the Stars page.

Spectral type

Wikipedia's Sun article is a great source of info on the Sun's spectral type (also called spectral class):

The Sun has a spectral class of G2V. "G2" means that it has a surface temperature of approximately 5,500 K, giving it a yellow color, and that its spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The "V" suffix indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium and is in a state of hydrostatic balance, neither contracting nor expanding over time.

Other stars

For other interesting stars see the Stars or Weird Stars pages.