white dwarf, Astronomy, General

Related Category: Astronomy, General

white dwarf, in astronomy, a type of star that is abnormally faint for its white-hot temperature (see mass-luminosity relation). Typically, a white dwarf star has the mass of the sun and the radius of the earth but does not emit enough light or other radiation to be easily detected. The physical conditions inside the star are quite unusual; the central density is about 1 million times that of water. The existence of white dwarfs is intimately connected with stellar evolution. The first white dwarf discovered (1844) was the faint companion in the binary star Sirius. Although invisible to the telescopes of the day, the white dwarf's mass was large enough to produce a noticeable wavy motion of its very bright partner as the two stars revolved around each other. It is believed that white dwarfs could represent as much as a third of the so-called dark matter in the universe.

The Columbia Electronic Encyclopedia Copyright © 2009, Columbia University Press.
Licensed from Columbia University Press. All rights reserved.

---

---