15 Facts About White dwarf

White dwarf is a stellar core remnant composed mostly of electron-degenerate matter.

White dwarf is very hot when it forms, but because it has no source of energy, it will gradually cool as it radiates its energy away.

Such densities are possible because white dwarf material is not composed of atoms joined by chemical bonds, but rather consists of a plasma of unbound nuclei and electrons.

Existence of a limiting mass that no white dwarf can exceed without collapsing to a neutron star is another consequence of being supported by electron degeneracy pressure.

The energy of the white dwarf can be approximated by taking it to be the sum of its gravitational potential energy and kinetic energy.

Since the white dwarf has no energy sink other than radiation, it follows that its cooling slows with time.

The white dwarf is kept from cooling very quickly only by its outer layers' opacity to radiation.

The first magnetic white dwarf to be discovered was GJ 742 which was identified by James Kemp, John Swedlund, John Landstreet and Roger Angel in 1970 to host a magnetic field by its emission of circularly polarized light.

Highly magnetized white dwarf in the binary system AR Scorpii was identified in 2016 as the first pulsar in which the compact object is a white dwarf instead of a neutron star.

Magnetic fields in a white dwarf may allow for the existence of a new type of chemical bond, perpendicular paramagnetic bonding, in addition to ionic and covalent bonds, resulting in what has been initially described as "magnetized matter" in research published in 2012.

The first variable white dwarf found was HL Tau 76; in 1965 and 1966, and was observed to vary with a period of approximately 12.

The composition of the white dwarf produced will depend on the initial mass of the star.

White dwarf is stable once formed and will continue to cool almost indefinitely, eventually to become a black dwarf.

White dwarf can be cannibalized or evaporated by a companion star, causing the white dwarf to lose so much mass that it becomes a planetary mass object.

The first observation of a metal-polluted white dwarf was by van Maanen in 1917 at the Mount Wilson Observatory and is recognized as the first evidence of exoplanets in astronomy.