white dwarf

American  

noun

Astronomy.

1. a star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars, beginning hot and white and ending cold and dark black dwarf.

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white dwarf British  

noun

1. one of a large class of small faint stars of enormous density (on average 10 ⁸ kg/m³) with diameters only about 1 per cent that of the sun, and masses less than the Chandrasekhar limit (about 1.4 solar masses). It is thought to mark the final stage in the evolution of a sun-like star

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white dwarf Scientific  

1. A small, extremely dense star characterized by high temperature and luminosity. A white dwarf is believed to be in its final stage of evolution, having either used up most of its nuclear fuel in its main-sequence stage, or else moved through a giant stage and shed any remaining fuel in its outer layer as a planetary nebula, leaving only a glowing core. Some 10 percent of all stars in the Milky Way are white dwarfs, but despite their intrinsic luminosity, they are so small that none are visible to the naked eye.

2. See Note at dwarf

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white dwarf Cultural  

1. A kind of star about the size of the Earth. White dwarfs represent a final stage of the life cycle of stars similar to the sun; they are formed when the stars use up their fuel and can no longer support nuclear reactions.

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Etymology

Origin of white dwarf

First recorded in 1920–25

Example Sentences

At the center of the Helix Nebula is a white dwarf, the exposed core left behind after the star shed its outer layers.

From Science Daily • Jan. 26, 2026

Intense radiation from the white dwarf energizes the surrounding gas, producing a range of environments.

From Science Daily • Jan. 26, 2026

A white dwarf forms when a star exhausts the hydrogen fuel needed for nuclear fusion in its core but lacks the mass required to explode as a core-collapse supernova.

From Science Daily • Jan. 8, 2026

In particular, the gravitational pull from a smaller white dwarf can raise internal heat within a larger but less massive companion.

From Science Daily • Dec. 2, 2025

A star like the Sun will end its days, as we have seen, as a red giant and then a white dwarf.

From "Cosmos" by Carl Sagan