Albireo

Star

Apparent magnitude

3.08 mag

Parallax

7.51 mas → about 434.3 light-years away

Spectral type

K3II+...

Right ascension

292.6803°

Declination

27.9597°

Designation

HR 7417

Bayer designation

β Cyg

HIP number

95947

IAU name adopted

2016-07-20

Name language

Arabic

Name origin (IAU)

The formation of this name begins with Ptolemy's name for the constellation Cygnus - ὄρνις, "the Bird". The Arabs transliterated this name as urnis. The Medieval Latin translator of the Arabic Almagest, in turn, did not recognize any Greek word behind urnis (or whatever Arabic corruption he may have read), so he merely transliterated it into a form which appeared int he manuscripts variously as eurisim, eirisun, eirism, etc. In a note appended to this Medieval Latin constellation name for Cygnus, one Latin commentator ventured to derive it from the name of an aromatic herb he knew: ireus. This erroneous commentary read, in brief part: "eirisim...ab ireo", or, "[the constellation name] eirisim...[coming] from [the word] ireus". Apparently in one manuscript of the Latin Almagest, the final word of this commentary, ab ireo, were written on the next line below the constellation title, where the descriptions of the stars begin. Since the first star entered in the Almagest under the constellation Cygnus is β Cyg, the words ab ireo seem to have been confused as a name for this star. "Arabicized" with the insertion of the letter "l", ab ireo, written as "Albireo", was applied as a star name to β Cyg by Early Modern times.

Source:IAU Working Group on Star Names · checked 2026-11-02 ↗ESA Hipparcos Catalogue (ESA Gaia Archive) · checked 2026-11-03 ↗