brown dwarf

brown dwarf

noun

Definition of BROWN DWARF

: a celestial object that is much smaller than a normal star and has insufficient mass to sustain nuclear fusion but that is hot enough to radiate energy especially at infrared wavelengths

First Known Use of BROWN DWARF

1978

brown dwarf

noun    (Concise Encyclopedia)

Astronomical object intermediate in mass between a planet and a star. Sometimes described as failed stars, brown dwarfs are believed to form in the same way as stars, from fragments of an interstellar cloud that contract into gravitationally bound objects. However, they do not have enough mass to produce the internal heat that in stars ignites hydrogen and establishes nuclear fusion. Though they generate some heat and light, they also cool rapidly and shrink; they may differ from high-mass planets only in how they form.