Glossary term: White Dwarf

Description: Stars with mass up to eight times the mass of the Sun are expected to end their lives as white dwarfs. This includes our Sun. White dwarfs have very high densities, and a typical white dwarf could have the mass of the Sun squeezed into a ball slightly larger than the size of the Earth. A white dwarf is no longer producing energy from nuclear reactions in its core, but shines due to its leftover energy. The hotter ones appear blue or white because of the energy they radiate due to the very high temperatures on their surfaces. The core of a white dwarf could be made up of helium or carbon–oxygen or oxygen–neon–magnesium depending on the initial mass of the star. It does not contract under self-gravity due to resistance within its interior from electron degeneracy pressure – a quantum phenomenon. Degeneracy pressure can only support white dwarfs with masses up to 1.4 times the mass of the Sun. Stellar remnants with masses greater than this limit (known as the Chandrasekhar limit) are either neutron stars or black holes.

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