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

Callingham and his collaborators are now trying to get more data from the most promising red dwarfs to see if and how their radio signals change over time, which could sort out whether they’re exoplanets.

From Popular-Science

He and his colleagues used a massive radio telescope called the Low Frequency Array or LOFAR to look at nearby red dwarfs in radio frequencies, and published their findings in the journal Nature Astronomy.

From Popular-Science

Thus, on average, red dwarfs should follow more elliptical orbits around the galaxy than young brown dwarfs do.

From Science News

On the positive side, red dwarfs abound, outnumbering all other stellar types put together, and brown dwarfs are also common.

From Science News

You might think that a smaller star would be a tamer star, but that’s actually not the case at all—red dwarfs produce stellar flares a lot more frequently than the sun does.

From Singularity Hub 

Gliese 581a is an “M dwarf” or “red dwarf” star, much less massive and hot than the Sun.

From The Daily Beast

The Red Dwarf alum did not initially set out to make a web series.

From The Daily Beast

They were approaching a red dwarf, the only planet-bearing sun in the vicinity.

From Project Gutenberg

The spines of a million needle-sharp mountains glittered in the red dwarf's feeble light.

From Project Gutenberg

The time required for the evolution of a star from red giant to red dwarf is not known, but it must be very great.

From Project Gutenberg