Stellar Designations and Names: A Cosmic Identifier Guide

In the vast expanse of our universe, stars hold a special place. They are identified through both stellar designations and names, which serve as unique identifiers to help astronomers keep track of these celestial bodies.

Introduction

While only a small fraction of known stars bear proper names, the majority have designated labels from various catalogues or no identifier at all. The history of star naming dates back to Hipparchus in the 2nd century BC, who enumerated approximately 850 naked-eye stars. This number was doubled by Johann Bayer in 1603. It wasn’t until the 19th century that star catalogues exhaustively listed all visible naked-eye stars. The Bright Star Catalogue, which includes stars of apparent magnitude 6.5 or brighter (stars visible to the naked eye from Earth), contains 9,096 stars . Modern catalogues list on the order of a billion stars, reflecting the estimated total of 200 to 400 billion stars in our own Milky Way galaxy.

Proper Names and Designations

Proper names for stars often have historical origins, with many being transliterated from Arabic or Chinese names. Due to variations in transliteration, the same star might have multiple spellings. Some names date back to the Middle Ages, while a few more have been introduced since then, such as ‘Sualocin’ for α Delphini and ‘Navi’ for γ Cassiopeiae .

The International Astronomical Union (IAU) is currently working on selecting and formalizing unique proper names for brighter naked-eye stars and other stars of popular interest. To the IAU, a name refers to the colloquial term used for a star in everyday speech, while a designation is solely alphanumerical and used almost exclusively in official catalogues and professional astronomy . Many of the names and some of the designations in use today were inherited from before the IAU’s establishment. New designations are being added continually. As of early 2019, the IAU had decided on over 300 proper names, primarily for brighter naked-eye stars .

Bright Star Catalogue: https://en.wikipedia.org/wiki/Bright_Star_Catalogue International Astronomical Union: https://www.iau.org/publications/names/