In 2016, the IAU mobilised the Working Group on Star Names (WGSN) under its Division C (Education, Outreach, and Heritage), whose purpose was to formally catalogue the names of stars, beginning with the brightest and best-known. The Working Group is composed of an assortment of astronomers from all over the world who bring different perspectives and experience to its decisions. Further details on the establishment of the group can be found in this press release.
Alphanumeric designations are useful for astronomers to officially identify the stars they study, but in many instances, for cases of bright stars, and stars of historical, cultural, or astrophysical interest, it can be more convenient to refer to them by a memorable name. Many such names are already in common parlance, and have been for a long time, but until the establishment of the WGSN there was no official, IAU-approved catalogue of names for the brightest stars in our sky.
The Working Group aims to solve the problems that have arisen over the centuries as different cultures and astronomers gave their own names to stars. Even until recently, some of the most famous stars in the sky — such as Sirius, Rigel and Betelgeuse — had no official spelling, some stars had multiple names, and identical names were sometimes used for completely different stars altogether. As an example, a cursory perusal through historical and cultural astronomy literature finds over 30 names for the star commonly known as Fomalhaut. While this particular spelling has seen the most use over the centuries, similar instances in literature have included Fom-al hut al-jenubi, Fomahandt, Fomahant, Fomal'gaut, Fomal'khaut, Fomalhani, Fomalhut, Formalhaut, Fumahant, Fumahaut, and Fumalhaut. By creating an IAU-endorsed stellar name catalogue, confusion can be reduced. The unique IAU star names will also not be available in the future to name asteroids, planetary satellites, and exoplanets so as to further reduce confusion.
To approve the list of star names, the WGSN is delving into worldwide astronomical history and culture, looking to determine the best-known stellar appellations to use as the officially recognised names. Such an exercise will continue to be the Group’s main aim for the next few years. Beyond this point, once the names many of the bright stars in the sky have been officially approved and catalogued, the WGSN will turn its focus towards establishing a format and template for the rules, criteria and process by which proposals for stellar names can be accepted from professional astronomers, as well as from the general public.
Although there is no rigid format that stellar names must follow — since they have their roots in many varied cultures and languages — the Working Group established some initial, basic guidelines, which build on the lessons from other IAU Working Groups. The guidelines outline a preference for shorter, one-word names that are not too similar to existing names for stars, planets or moons, as well as those that have roots in astronomical and historical cultural heritage from around the world.
Before the establishment of the WGSN, the IAU had only ever officially approved the names of 14 stars, in connection with efforts to catalogue the names of newly discovered exoplanets.