Astronomers long believed this intense pressure could cause the carbon interiors of white dwarfs to crystallize. In 2004 the discovery of BPM-37093, a star that is located 50 light-years from the earth in the constellation Centaurus and is both pulsating and has sufficient mass to have a crystalline interior. By measuring the pulsations it was possible to study this white dwarf's interior and determine that it had crystallized to form an enormous diamond, some 950 mi (1,500 km) wide. Were it a diamond as we commonly know it, it would weigh some 10 billion trillion trillion carats.

The first white dwarf discovered (1844) was the faint companion in the binary star Sirius. Although invisible to the telescopes of the day, the white dwarf's mass was large enough to produce a noticeable wavy motion in its very bright partner as the two stars revolved around each other. It is believed that white dwarfs could represent as much as a third of the so-called dark matter in the universe.

Although they should exist in large numbers, brown dwarfs are difficult to find using conventional astronomical techniques because they are dim compared with true stars. A number of brown dwarfs have been identified, the first in the Pleiades star cluster in 1995. The first X-ray-emitting brown dwarf was detected in Chamaeleon dark cloud number I in 1998. A year later, several so-called methane dwarfs were discovered; these are thought to be older brown dwarfs that have cooled sufficiently over billions of years so that large amounts of methane could form in their atmospheres. The closest brown dwarf to Earth, Epsilon Indi B, less than 12 light-years from the Sun, was discovered in 2003.

Brown dwarfs belong to the "T dwarf" category of objects straddling the domain between stars and giant planets. Because brown dwarfs are typically 10-80 times the mass of Jupiter, some of the large extrasolar bodies discovered orbiting stars may be brown dwarfs rather than giant Jupiterlike planets. Observations of 100 young brown dwarfs in the Orion Nebula in 2001 strongly supported the theory that they originate as failed stars; many of the brown dwarfs were surrounded by disks of dust and gas that conceivably could condense and conglomerate to create planets orbiting them. Brown dwarfs are believed to play an important role in the process of stellar evolution. They are a component of the dark matter that along with dark energy may account for more than 90% of the mass of the universe.

Any of a class of small, faint stars representing the end point of the evolution of stars without enough mass to become neutron stars or black holes. Named for the white colour of the first ones discovered, they actually occur in a variety of colours depending on their temperature. They are extremely dense, typically containing the mass of the Sun within the volume of the Earth. White dwarfs have exhausted all their nuclear fuel and cannot produce heat by nuclear fusion to counteract their own gravity, which compresses the electrons and nuclei of their atoms until they prevent further gravitational contraction. When a white dwarf's reservoir of thermal energy is exhausted (after several billion years), it stops radiating and becomes a cold, inert stellar remnant, sometimes called a black dwarf. White dwarf stars are predicted to have an upper mass limit, known as the Chandrasekhar limit (see Subrahmanyan Chandrasekhar), of about 1.4 times the Sun's mass. Dying stars that are more massive undergo a supernova explosion. As members of binary stars, white dwarf stars play an essential role in the outbursts of novas.

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Any star of average or low luminosity, mass, and size, including white dwarf stars and red dwarf stars. Dwarf stars include most main-sequence stars (see Hertzsprung-Russell diagram), including the Sun. Their colour can range from blue to red, corresponding to temperatures varying from over 17,500 °F (10,000 °C) to a few thousand degrees.

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Body, other than a natural satellite (moon), that orbits the Sun and that is, for practical purposes, smaller than the planet Mercury yet large enough for its own gravity to have rounded its shape substantially. The International Astronomical Union adopted this category of solar system bodies in August 2006, designating Pluto, the even more-remote object Eris, and the asteroid Ceres as the first members of the category. Unlike major planets, these three bodies are not massive enough and are in orbits too elliptical, too inclined, or both to have swept up most smaller nearby bodies by gravitational attraction; they thus failed to grow larger.

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Creeping perennial herbaceous plant (Cornus canadensis), also called dwarf cornel, of the dogwood family. The small and inconspicuous yellowish flowers, grouped in heads surrounded by four large and showy white (rarely pink) petal-like bracts, give rise to clusters of red fruits. Bunchberry is found in acid soils, bogs, and upland slopes in Asia and from Greenland to Alaska, and south as far as Maryland, New Mexico, and California.

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Growth retardation resulting in abnormally short adult stature. It is caused by a variety of hereditary and metabolic disorders. Pituitary dwarfism is caused by insufficient growth hormone. Hereditary dwarfisms include achondroplasia, with normal trunk size but short limbs and a large head; hypochondroplasia, similar except for normal head size; and diastrophic dwarfism, with progressive, crippling skeletal deformities. Intelligence is normal in these forms of dwarfism. Some kinds include intellectual disability. Dwarfism may also result from inadequate nutrition in early life (see rickets).

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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.

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