brown dwarf

[ broun-dwawrf ]

/ ˈbraʊn ˈdwɔrf /

Save This Word!

noun Astronomy.

a celestial object smaller than a small star but larger than a giant planet: believed to form as stars do, from collapsing clouds of gas and dust, brown dwarfs are sometimes called failed stars as they are not dense enough to initiate nuclear fusion, leaving them much dimmer and cooler than stars.

QUIZ

ARE YOU A TRUE BLUE CHAMPION OF THESE "BLUE" SYNONYMS?

We could talk until we're blue in the face about this quiz on words for the color "blue," but we think you should take the quiz and find out if you're a whiz at these colorful terms.

Question 1 of 8

Which of the following words describes “sky blue”?

navy

beryl

azure

TAKE THE QUIZ TO FIND OUT

Meet Grammar Coach

Write or paste your essay, email, or story into Grammar Coach and get grammar help

Improve Your Writing

Meet Grammar CoachImprove Your Writing

Origin of brown dwarf

First recorded in 1975–80

Words nearby brown dwarf

brown coal, brown coat, brown cow, brown creeper, Brown Deer, brown dwarf, Browne, brown earth, browned-off, brown-eyed Susan, brownface

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use brown dwarf in a sentence

Below this temperature, though, “it’s all brown dwarfs,” Hsu says.
Here’s how cool a star can be and still achieve lasting success|Ken Croswell|August 23, 2021|Science News
In contrast, brown dwarfs glow red primarily from the heat of their birth, but then their nuclear activity sputters out, causing them to cool and fade.
Here’s how cool a star can be and still achieve lasting success|Ken Croswell|August 23, 2021|Science News
This is the temperature that a new study says separates red dwarf stars, which shine for a long time, from failed stars known as brown dwarfs.
Here’s how cool a star can be and still achieve lasting success|Ken Croswell|August 23, 2021|Science News
Dupuy says additional red and brown dwarfs should be observed to verify the finding.
Here’s how cool a star can be and still achieve lasting success|Ken Croswell|August 23, 2021|Science News

It seemed to be about half the mass of Jupiter, too puny to be a brown dwarf.
A century of astronomy revealed Earth’s place in the universe|Lisa Grossman|July 21, 2021|Science News
There was deep brown flesh, and bronze flesh, and pallid white flesh, and flesh turned red from the hot sun.
Powerful Congressman Writes About ‘Fleshy Breasts’|Asawin Suebsaeng|January 7, 2015|DAILY BEAST
They became so brown and shriveled that they looked like walking beef jerky with New York accents.
Powerful Congressman Writes About ‘Fleshy Breasts’|Asawin Suebsaeng|January 7, 2015|DAILY BEAST
The smell of grilled meat mixes with the exotic wafts of cinnamon tea served with a mush of sweet brown dessert.
The Photographer Who Gave Up Manhattan for Marrakech|Liza Foreman|January 6, 2015|DAILY BEAST
The Supreme Court eventually stepped in and ended legal segregation in the landmark 1954 decision, Brown v. Board of Education.
The ‘No Child’ Rewrite Threatens Your Kids’ Future|Jonah Edelman|January 3, 2015|DAILY BEAST
Estee Lauder has not crumbled to dust because the perfect brown face of Joan Smalls represents it.
One Vogue Cover Doesn’t Solve Fashion’s Big Race Problem|Danielle Belton|January 2, 2015|DAILY BEAST
The case was an assault and battery that came off between two men named Brown and Henderson.
The Book of Anecdotes and Budget of Fun;|Various
"There's just one thing I'd like to ask, if you don't mind," said Cynthia, coming suddenly out of a brown study.
The Boarded-Up House|Augusta Huiell Seaman
It separates into three layers upon standing—a brown deposit, a clear fluid, and a frothy layer.
A Manual of Clinical Diagnosis|James Campbell Todd
I pictured him as slim and young looking, smooth-faced, with golden curly hair, and big brown eyes.
The Boarded-Up House|Augusta Huiell Seaman
Mr. Brown seizes the proffered member, and gives it as hearty a pressure as the publicity of the occasion will permit.
Physiology of The Opera|John H. Swaby (AKA "Scrici")

British Dictionary definitions for brown dwarf

brown dwarf

noun

a type of celestial body midway in mass between a large planet and a small star

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for brown dwarf

brown dwarf

A celestial body with insufficient mass to sustain the nuclear fusion that produces radiant energy in normal stars. It is believed that a brown dwarf is formed with enough mass to start nuclear fusion in its core, but without enough for the fusion to become self-sustaining. Theory suggests that a body with about one percent of the mass of the Sun-or ten times the mass of Jupiter-can generate this initial fusion, but that it needs at least eight percent of the Sun's mass to sustain the fusion. After the fusion ends, the dwarf still glows for a period from radiating heat, with a surface temperature of about 2,500°K (4,532°F) or less. See Note at dwarf star.