double star designated Beta Cygni

Albireo, also called Beta Cygni, is a binary star found in the Cygnus constellation. It consists of two stars, a red giant called Albireo Aa and a blue main sequence star named Albireo Ac.[1] Another blue star named Albireo B could be part of the system.

Albireo A and B.


  1. Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series. 143 (2): 513–537. Bibcode:2002ApJS..143..513G. doi:10.1086/342942. S2CID 120976247.