Triple star system
From Free net encyclopedia
A triple star system (also trinary or ternary) consists of three gravitationally bound stars. The stars orbit a common center of mass, usually so that two of the stars form a close binary star and the third is further away. This configuration is often called a hierarchical triple star system. Multiple stars containing more than three stars can usually be decomposed to binaries and single stars that are in a hierarchically bound system.
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Examples
- Alpha Centauri is composed of a main binary yellow dwarf pair (Alpha Centauri A and Alpha Centauri B), and an outlying red dwarf (Proxima Centauri)
- HD 188753 is a triple star system located approximately 149 light years away from Earth in the constellation Cygnus. The system is composed of a yellow dwarf, an orange dwarf, and a red dwarf.
- Polaris, the north star, is a triple star system in which the closer companion star is extremely close to the main star---so close that it was only known from its gravitational tug on Polaris A until it was photographed by Hubble Space Telescope in 2006.
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