a cold, dark star that is too small to initiate the nuclear reactions that generate heat and light.
a type of celestial body midway in mass between a large planet and a small star
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.
noun an intrazonal soil of temperate humid regions typically developed under deciduous forest into a dark rich layer (mull): characteristic of much of southern and central England Historical Examples The Black Pearl Mrs. Wilson Woodrow A Maid of the Kentucky Hills Edwin Carlile Litsey The Octopus Frank Norris Chambers’s Elementary Science Readers Various In Pastures […]
a composite plant, Rudbeckia triloba, of the southeastern U.S., having a single flower with yellow rays darkening to an orange orbrown at the base and a brownish-black disk.
brown eyes Contemporary Examples Jeff Goldblum on Theresa Rebeck’s ‘Seminar,’ Celebrity Death Hoaxes & More Lorenza Muñoz November 7, 2012 Speed Read: Juiciest Bits From the Tommy Mottola Memoir ‘Hitmaker’ Kevin Fallon January 30, 2013 When Gary Wright Met George Harrison: Dream Weaver, John and Yoko, and More Gary Wright September 28, 2014 Historical Examples […]
brownish-yellow adipose tissue in the upper back, or interscapular, region of many mammals, most conspicuously in hibernating species and human newborns, composed of numerous innervated fat cells that can produce heat during cold stress; thermogenic tissue. noun tissue composed of a type of fat cell that dissipates as heat most of the energy released when […]