Binary stars

(Last edited: Friday, 1 September 2023, 12:27 PM)


Center for High Angular Resolution Astronomy (2008, August 21). Beta Lyrae - CHARA (inverted colors). wikimedia commons.

Short Definition:

A system composed of two stars in which both share a common centre of revolution or one revolves around the other.

Detailed Definition:

A binary star is a pair of stars in orbit around their common centre of gravity. The term is different from a double star, which refers to any two stars close together in the sky. If components in binary star systems are close enough, they can gravitationally distort their mutual outer stellar atmospheres. In some cases, binary systems can exchange mass, evolving in a way which is unattainable for single stars.


The term binary was first used in the context of space terminology by Sir William Herschel in 1802, in one of his works regarding the observation of double stars.

Binary - "dual, twofold, double," mid-15c., from Late Latin binarius

Sample Sentence(s):

One of the examples of a binary star is Sirius, the brightest star in the night sky.

Translations of Terms/Concepts into Partner Languages

French: Étoile binaire

German: Doppelstern

Polish: Gwiazdy podwójne

Swedish: Binär Stjärna

Links to Videos/Articles:

» Dictionary of Space Concepts