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

According to the team's models, these gases form when ultraviolet radiation from the host star, the red dwarf L 98-59, drives chemical reactions.

From Science Daily • Mar. 17, 2026

The discovery, reported in Science, centers on a small, faint red dwarf star that is cooler and less massive than the Sun.

From Science Daily • Feb. 14, 2026

The closest red dwarf to us is Proxima Centauri.

From Space Scoop • Nov. 28, 2025

Hurley-Walker says it’s a hint that the LPT is actually emanating from a white dwarf, too small and dim to be observed directly, in a binary orbit with the red dwarf.

From Science Magazine • Dec. 3, 2024

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

From "The Last Cuentista" by Donna Barba Higuera