red dwarf

American  

noun

Astronomy.

1. any of the faint reddish stars having diameters about half that of the sun and low surface temperatures, about 2000–3000 K; a main sequence star of spectral type M.

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red dwarf British  

noun

1. one of a class of small cool main-sequence stars

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red dwarf Scientific  

1. A small, dim star with relatively cool surface temperatures, positioned to the lower right on the main sequence in the Hertzsprung-Russell diagram. Red dwarfs, at about 0.1 to 0.5 solar mass, consume their nuclear fuel very slowly and live for about 100 billion years. Although they are difficult to see, they are so long-lived that they are likely the most abundant type of star; of the 30 nearest stars to Earth, 21 are red dwarfs, including the closest star, Proxima Centauri.

2. See Note at dwarf star

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Etymology

Origin of red dwarf

First recorded in 1915–20

Example Sentences

See Examples For:

red dwarf

LHS 1140 b circles a red dwarf star within its habitable zone.

From Science Daily ● Jul. 21, 2026

For instance, G 203-47's red dwarf rotates once every 100 or so days, but orbits its white dwarf every 14.9 days, meaning they are not tidally synced.

From BBC ● Jul. 14, 2026

An artist's impression of a red dwarf with a white dwarf binary companion behind, with the diameters shown to scale.

From BBC ● Jul. 14, 2026

LHS 1903 is a small, cool red dwarf star known as an M-dwarf.

From Science Daily ● May 21, 2026

And high above them all, looking down, is the red dwarf, just like Dad said.

From "The Last Cuentista" by Donna Barba Higuera