red dwarf

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.

red dwarf

noun

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

red dwarf

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

Word History and Origins

Origin of red dwarf¹

First recorded in 1915–20

Example Sentences

The host star, called Gliese 12, is a cool red dwarf located almost 40 light-years away in the constellation Pisces.

From Science Daily

This is made up of seven planets, all roughly in Earth's size range and likely rocky, orbiting a red dwarf star.

From Science Daily

These so-called red dwarf or M dwarf stars also live 10 times as long as stars like ours and are the most numerous in our galaxy, outnumbering stars like ours 10 to 1.

From Salon

This is especially true for systems like TRAPPIST-1, since the system is centred around a red dwarf star which can be particularly active with starspots and frequent flare events.

From Science Daily

At the heart of this system is a small, dim star called a red dwarf.

From Scientific American