White dwarf

A white dwarf, also called a degenerate dwarf, is a stellar remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, and its volume is comparable to that of Earth. A white dwarf's faint luminosity comes from the emission of stored thermal energy. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Luyten in 1922.

White dwarfs are thought to be the final evolutionary state of stars (including our Sun) whose mass is not high enough to become a neutron star—over 97% of the stars in the Milky Way.^{, §1.} After the hydrogen–fusing period of a main-sequence star of low or medium mass ends, a star will expand to a red giant during which it fuses helium to carbon and oxygen in its core by the triple-alpha process. If a red giant has insufficient mass to generate the core temperatures required to fuse carbon, around 1 billion K, an inert mass of carbon and oxygen will build up at its center. After shedding its outer layers to form a planetary nebula, it will leave behind this core, which forms the remnant white dwarf. Usually, therefore, white dwarfs are composed of carbon and oxygen. If the mass of the progenitor is between 8 and 10.5 solar masses (M_☉), the core temperature is sufficient to fuse carbon but not neon, in which case an oxygen–neon–magnesium white dwarf may form. Stars of very low mass will not be able to fuse helium, hence, a helium white dwarf may form by mass loss in binary systems.

White dwarf (disambiguation)

A white dwarf is a compact star that is no longer generating energy through nuclear fusion at its core.

White dwarf may also refer to:

White Dwarf (magazine)

White Dwarf is a magazine published by British games manufacturer Games Workshop serving as a promotions and advertising platform for Games Workshop and Citadel products.

On launch it initially covered a wide variety of fantasy and science-fiction role-playing games (RPGs) and board games, particularly the role playing games Advanced Dungeons & Dragons (AD&D), RuneQuest and Traveller (which were all published by other games companies), the magazine underwent a major change in style and content in the late 1980s and is now dedicated exclusively to the miniature wargames produced by Games Workshop, mainly the core systems of Warhammer Fantasy Battle, Warhammer 40,000 and The Hobbit: An Unexpected Journey Strategy Battle Game.

History

Steve Jackson and Ian Livingstone initially produced a newsletter called Owl and Weasel, which ran for twenty-five issues from February 1975 before it evolved into White Dwarf.

Originally scheduled for May/June 1977 but first published one month later on a bimonthly schedule with an initial (and speculative) print run of 4,000, White Dwarf continued the fantasy and science fiction role-playing and board-gaming theme developed in Owl and Weasel but, owing to the increase in available space, began to produce reviews, articles and scenarios to a greater depth than had previously been possible.