This month . . . Dwarfs. No, not Snow White and her seven companions. Dwarf stars. They come in a variety of colours and are the last stage in a star’s life. It is believed our own Sun will become a white dwarf at the end of its life.
White dwarf stars are relatively rare. There are only eight known white dwarf stars in the 100 star systems closest to the Sun, with the closest known one to us being Sirius B, 8.6 light years away.
White dwarfs are incredibly dense. A teaspoon of white dwarf material would weigh about 5 tons !
Red dwarf stars have very long life spans and live for trillions of years. Their masses can be used to estimate the age of star clusters of all types as well as determining the age of the Galactic disc and Galactic halo. The illustration below is o Red Dwarf with an orbiting exoplanet Credit: NASA/ESA/G. Bacon (STScI)
Brown dwarf stars are sometimes referred to as “”failed stars””. They form in the same manner as normal stars but never accumulate enough mass to begin nuclear fusion in their cores. Brown dwarf stars are not brown, despite their name. They are divided into four spectral classes and occur in a wide variety of colours mostly invisible to the human eye.