IAU Working Group on Star Names

The IAU Working Group on Star Names (WGSN) is an expert body established by the International Astronomical Union in May 2016 to bring greater consistency to the proper names used for stars in international astronomy. It operates within IAU Division C – Education, Outreach and Heritage. Its work addresses a distinction that is important to the IAU: a star name is generally a cultural or colloquial term used in ordinary discussion, whereas a designation is an alphanumeric identifier used primarily in scientific catalogues and professional research. Historical forms such as Bayer designations are treated as a special case of designation rather than as ordinary proper names. The group’s initial terms of reference, approved by the IAU Executive Committee on 6 May 2016 for the 2016–2018 period, called for the development of guidelines for proposing and adopting stellar names, research into names found in historical and scientific literature, adoption of unique names for stars with scientific or cultural importance, and publication of an official catalogue. The resulting IAU Catalog of Star Names is the group’s principal reference output. The WGSN initially concentrated on the brightest several hundred stars with established names, seeking to resolve spelling, attribution, and identification issues before expanding its attention to less prominent stars and other stellar objects. Its naming principles emphasize the preservation of world heritage and the use of established cultural names rather than newly invented ones. Names are normally expected to be short, pronounceable, distinctive, and non-offensive. The guidelines discourage names that resemble existing astronomical names and generally prohibit names of individuals for bright stars, although historical exceptions may be retained. Names tied principally to political or military events, commercial entities, pets, or acronyms are also excluded. The group recognizes that some names approved through the IAU’s 2015 NameExoWorlds process were adopted by a separate IAU public-naming working group and subsequently incorporated into the official star-name system. The WGSN assigns names to individual stellar components rather than automatically applying one name to an entire multiple-star system. Thus, a name such as Fomalhaut refers specifically to the identified primary component, while informal labels for companions are not normally included in the official list unless their component identifiers are clearly specified. The group also adopted guidance for Chinese star names in 2017, including preference for established historical sources and Pinyin transliteration, while cautioning against assigning Chinese asterism names directly to individual stars where doing so could create ambiguity. The group’s first bulletin in July 2016 documented 125 approved or recognized names. Additional batches followed through 2016, 2017, and 2018, including traditional names, historically recovered names, and names associated with exoplanet systems. Examples include Cervantes for Mu Arae, Copernicus for 55 Cancri A, Cor Caroli for Alpha Canum Venaticorum, and the historical name Barnard’s Star. The WGSN continues to maintain and update the IAU Catalog of Star Names. In 2024 it also launched the All Skies Encyclopaedia, a project documenting cultural names of stars and constellations and hosted by the University of Jena. The WGSN is therefore best understood not as a commercial brand but as an international nomenclature and heritage initiative whose outputs support scientific communication, education, public outreach, and the preservation of astronomical traditions.

The IAU Working Group on Star Names was established by the International Astronomical Union in May 2016 and placed within Division C – Education, Outreach and Heritage. Its creation reflected the need for an internationally coordinated approach to proper stellar names. Astronomers already used a mixture of traditional names, historical spellings, transliterations, catalogue identifiers, and newer names associated with exoplanet discoveries. Without a central process, the same star could appear under variant spellings or names with uncertain scope and provenance. The IAU approved the group’s initial terms of reference at an Executive Committee meeting on 6 May 2016. These terms required the WGSN to formulate naming rules, investigate candidate names in the literature, adopt unique names for stars of scientific and historical value, and compile an official catalogue for international use. The group’s remit also required it to distinguish names from designations. Proper names are normally cultural or colloquial expressions, while designations are alphanumeric identifiers used in technical catalogues. Historical Bayer forms occupy a special position and are treated as designations even when they are widely familiar outside professional astronomy. During its first phase, the WGSN focused on bright stars with names documented in historical or scientific sources. Its goal was not simply to generate attractive names, but to identify the most established forms, determine which object a name referred to, and make the spelling and usage consistent. The group encouraged names that preserve world heritage and reflect existing cultural practice. Its preliminary guidelines favored names of roughly four to sixteen characters, pronunciation in at least one language, distinctiveness, and avoidance of offensive meanings or close similarity to other astronomical names. Newly contrived names were discouraged, as were names based on commercial activity, political or military events, pets, and acronyms. Naming bright stars after individuals was generally prohibited, except where a historically established exception justified retention. The first WGSN bulletin, issued in July 2016, listed 125 stars. It included the first two WGSN approval batches from June and July and also incorporated names arising from the 2015 NameExoWorlds campaign. Subsequent approvals were recorded in later 2016 and in several updates during 2017 and 2018. These decisions covered traditional names, historically documented names, and names assigned to host stars in systems with publicly named exoplanets. Examples include Cervantes for Mu Arae, honoring Miguel de Cervantes; Copernicus for 55 Cancri A, honoring Nicolaus Copernicus; Cor Caroli for Alpha Canum Venaticorum; and Barnard’s Star, whose historical association with astronomer E. E. Barnard was formally recognized. A significant technical policy concerned multiple-star systems. The WGSN chose to attach a proper name to a particular stellar component rather than automatically to every member of a physical system. The catalogue therefore uses identifiers from the Washington Double Star Catalog when needed. If no component is specified, the name is generally understood to apply to the visually brightest component. Informal labels for companions may be useful in conversation but are not treated as official WGSN names unless formally identified. The group also addressed cultural and linguistic practice. In 2017 it adopted general guidance for Chinese star names, treating The Chinese Sky During the Han: Constellating Stars and Society as an authoritative reference for early identifications and spellings, preferring Pinyin, and advising against assigning Chinese asterism names directly to individual stars when that could cause ambiguity. More broadly, its programme sought to examine astronomical history and cultural traditions worldwide rather than relying only on modern English-language usage. The WGSN’s continuing output is the IAU Catalog of Star Names, which records approved names and their associated stellar identifiers. The catalogue has been maintained as an evolving reference rather than a one-time publication. In 2024, the group expanded its public documentation work through the All Skies Encyclopaedia, an online resource for cultural names of stars and constellations hosted by the University of Jena. Together, the catalogue, bulletins, guidelines, and encyclopaedia position the WGSN as an international nomenclature authority linking professional astronomy with education, public engagement, and preservation of astronomical heritage.

• 2024

  All Skies Encyclopaedia launched

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The WGSN launched an online resource documenting cultural names of stars and constellations.

• 2018

  Further catalogue additions recorded

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The group continued adding approved names through updates issued in 2018.

• 2017

  Chinese naming guidance adopted

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The WGSN adopted general principles for Chinese star names, including historical-source preference and Pinyin transliteration.

• 2016

  WGSN established

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The International Astronomical Union established the Working Group on Star Names in May 2016 under Division C – Education, Outreach and Heritage.

• 2016

  Initial terms of reference approved

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The IAU Executive Committee approved the group’s initial 2016–2018 mandate, covering naming guidelines, historical research, name adoption, and catalogue publication.

• 2016

  First bulletin published

  [1]IAU Working Group on Star Namesen.wikipedia.org

  The first bulletin recorded 125 approved or recognized stellar names.

An authoritative international standard-setting and cultural-heritage body for proper star names, balancing historical usage, global astronomical traditions, scientific precision, and public accessibility.

• Astronomical reference catalogue · 2016

  IAU Catalog of Star Names

  The WGSN’s continuously updated catalogue of officially approved proper names for stars. Entries connect a name with a specific astronomical object and, where necessary, a component identifier for a multiple-star system. The catalogue is intended to provide a consistent international reference for scientific communication, education, and public outreach.

• Standards documentation · 2016

  WGSN bulletins

  Periodic publications recording batches of adopted names, naming decisions, and related policy information. The bulletins document the group’s early work and provide a historical record of how the official name catalogue developed.

• Cultural astronomy reference · 2024

  All Skies Encyclopaedia

  An online encyclopaedia documenting cultural names of stars and constellations. Launched in 2024 and hosted by the University of Jena, it extends the WGSN’s preservation and public-education work beyond the formal list of approved IAU star names.

• 2015NameExoWorlds

  International

  The IAU public naming campaign for exoplanets and their host stars produced names that were reviewed and adopted through the relevant IAU process. The WGSN recognized these names within its star-name catalogue, including Cervantes and Copernicus.

  Outcome. Several campaign-approved host-star names became part of the official IAU star-name system.

  Source

• 2017

  Adopt Chinese star-name guidelinesStrategy

  Background

  Chinese astronomical traditions contain established historical identifications and naming conventions that require careful treatment in an international catalogue.

  Action taken

  The group favored authoritative historical scholarship, discouraged potentially confusing use of asterism names for individual stars, and preferred Pinyin spelling.

  Aftermath

  The guidelines provided a consistent framework for representing Chinese stellar names in international usage.

  Source

• 2016

  Prioritize bright, historically named starsStrategy

  Background

  At the beginning of its programme, the group needed to establish consistency for the most visible and widely discussed stars before addressing fainter objects and broader proposal mechanisms.

  Action taken

  The WGSN concentrated on the brightest few hundred stars with published names and on compiling culturally significant stellar names.

  Aftermath

  This work produced the first catalogue batches and established a foundation for later naming rules and wider historical research.

  Source

• 2016

  Adopt component-specific naming for multiple-star systemsStrategy

  Background

  Traditional usage sometimes applied a familiar name ambiguously to a system containing several physically related stars.

  Action taken

  The WGSN decided that proper names should identify individual stellar components, using Washington Double Star Catalog identifiers where necessary.

  Aftermath

  The policy improved precision in the official catalogue while leaving informal companion nicknames outside the approved-name list.

  Source

1. 1IAU Working Group on Star Namesen.wikipedia.org
2. 2IAU Working Group on Star Names official websitepas.rochester.edu