Beta Centauri

Beta Centauri, also called Hadar, is a bright multiple-star system in Centaurus about 390 light-years from Earth. Its two brightest components are hot, massive stars.

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Centaurus: A large constellation in the southern celestial hemisphere, named for the mythological centaur. Beta Centauri is one of Centaurus’s brightest stars and lies near its southern end.
Stellar evolution: The sequence of physical changes a star undergoes from formation through its final state. The massive components of Beta Centauri evolve much faster than Sun-like stars.
Hadar: The traditional name for Beta Centauri, derived from an Arabic word associated with the ground or settlement. Hadar is the star’s common proper name, used alongside Beta Centauri.
Massive star: A star substantially more massive than the Sun, with high luminosity and a comparatively short lifetime. The system’s bright components belong to the hot, high-mass stellar population.
Multiple star: A stellar system in which two or more stars are gravitationally bound or appear close together in the sky. Beta Centauri’s components make it a system rather than a single star.
Spectroscopic binary: A binary star whose orbital motion is detected through periodic shifts in its spectral lines. Radial-velocity measurements help establish the close stellar components in Beta Centauri.
Agena: A traditional name for Beta Centauri, also used for the star’s principal component. Agena is an alternate proper name encountered in star catalogs and sky guides.
B-type star: A hot, blue-white star whose spectrum is classified as type B. The principal stars in Beta Centauri are classified among the early, hot stellar types.
Bayer designation: A stellar naming system that pairs Greek letters with constellation names, introduced by Johann Bayer. The name Beta Centauri identifies the star as the constellation’s second-lettered Bayer star.
Visual binary: A pair of stars whose orbital relationship can be studied by resolving their apparent positions in the sky. The wider components can be distinguished through their changing angular separation.