Longman Dictionary of Contemporary English
Wiktionary
n. (context star English) A dying star of low or medium mass, more solid and dense but less bright than the sun.
WordNet
n. a faint star of enormous density [syn: white dwarf star]
Wikipedia
White Dwarf is a magazine published by British games manufacturer Games Workshop serving as a promotions and advertising platform for Games Workshop and Citadel Miniatures 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.
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, while its volume is comparable to that of Earth. A white dwarf's faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf wherein mass is converted to 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. The universe has not existed long enough to experience a white dwarf releasing all of its energy as it will take close to a trillion years.
White dwarfs are thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star, including the Earth's Sun and over 97% of the other stars in the Milky Way. After the hydrogen- fusing period of a main-sequence star of low or medium mass ends, such 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 a star sheds its outer layers and forms a planetary nebula, it will leave behind this core, which is 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 , 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.
The material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy. As a result, it cannot support itself by the heat generated by fusion against gravitational collapse, but is supported only by electron degeneracy pressure, causing it to be extremely dense. The physics of degeneracy yields a maximum mass for a non-rotating white dwarf, the Chandrasekhar limit—approximately 1.46 —beyond which it cannot be supported by electron degeneracy pressure. A carbon-oxygen white dwarf that approaches this mass limit, typically by mass transfer from a companion star, may explode as a type Ia supernova via a process known as carbon detonation. ( SN 1006 is thought to be a famous example.)
A white dwarf is very hot when it forms, but because it has no source of energy, it will gradually radiate its energy and cool. This means that its radiation, which initially has a high color temperature, will lessen and redden with time. Over a very long time, a white dwarf will cool and its material will begin to crystallize (starting with the core). The star's low temperature means it will no longer emit significant heat or light, and it will become a cold black dwarf. The length of time it takes for a white dwarf to reach this state is calculated to be longer than the current age of the universe (approximately 13.8 billion years), and it is thought that no black dwarfs yet exist. The oldest white dwarfs still radiate at temperatures of a few thousand kelvin.
White Dwarf is a 1995 science fiction TV movie written by Bruce Wagner, directed by Peter Markle, and produced by Francis Ford Coppola, Robert Halmi Sr. and Bruce Wagner for American Zoetrope. Originally intended as a television pilot, the film first aired on the Fox Network on May 23, 1995. While expected to be well received, the film instead garnered generally negative reception. Negative reception notwithstanding, the project received a 1995 ASC Awards nomination for 'Outstanding Achievement in Cinematography'.
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 (dirigible), a human powered dirigible that has set several world records
- White Dwarf (magazine), a game magazine published by Games Workshop
- "White Dwarf", a song by a-ha from Analogue
- Grombrindal the White Dwarf, a dwarf character in Warhammer Fantasy
- White Dwarf (1995 film), a 1995 science fiction television film directed by Peter Markle, starring Neal McDonough
- White Dwarf (2012 film), a 2012 film starring Ben Savage
Usage examples of "white dwarf".
Jaina did not understand why the white dwarf star did not look like a big jewel, a huge diamond in space.
His short stories have appeared in The Year's Best SF, Zenith, White Dwarf and Interzone.
Ivarr leaped after him, but came to a standstill a moment later, wondering why he should bother about a wretched old white dwarf.
And if we fail--and we have to face the fact that we might fail--then at least we will return with considerable data on a dozen different stars, a white dwarf, a blue-white hot star, a Solar look-alike, a close binary, and so on.
When a not too massive star has used up its nuclear fuel, it collapses into a white dwarf.
Zub'daki's interest lies in the white dwarf itself, and the sheer amount of matter approaching it like flotsam in a whirling drain.
The sun, as its energy resources steadily diminish even further, will eventually blow off its outer layers of gas and shrink to end its life, ten billion years from now, as a dense white dwarf star not much bigger than today's Earth.
After gradually expanding into a planet-blistering red giant, it will begin to collapse, until, after a few hundred million years, it will calm down into the lonely insignificance of what is termed a white dwarf star - a tiny, phantom world of useless matter, a little larger than Earth.