Wikipedia:Naming conventions (astronomical objects)

General guidelines[edit]

Wikipedia's article titling policy states that generally, article naming should give priority to what the majority of English speakers would most easily recognize, with a reasonable minimum of ambiguity, while at the same time making linking to those articles easy. Names of Wikipedia articles should be optimized for readers over editors, and for a general audience over specialists. Wikipedia determines the recognizability of a name by seeing what verifiable reliable sources in English call the subject.

Common names[edit]


Common names should be used for article names in preference to official, IAU-sanctioned names where the former are widely used and are unambiguous.

Reference information on astronomical names[edit]

The SIMBAD website and the NASA/IPAC Extragalactic Database (NED) are both professional astronomy resources that can be used to check for accepted alternate designations for individual objects, including traditional names. However, neither website necessarily lists the designations in the order of most common use; the criteria below must still be applied. Note that SIMBAD contains broad information on objects inside and outside the Milky Way, whereas NED primarily contains information on extragalactic objects (i.e. objects outside the Milky Way). Therefore, it is recommended that SIMBAD be used for checking the names of objects primarily within the Milky Way and that both SIMBAD and NED be used for checking names for objects outside the Milky Way. Also note that neither website contains any information on objects within the Solar System.


In general, the official name of an object should be used (e.g. Jupiter). If another object shares a name with something more notable, the type of object should follow in parentheses. (e.g. Mercury (planet))


As per the guideline Wikipedia:Naming conventions (capitalization), where a word such as "Group", "Cluster" or "Star" is part of the object's proper name, this should be capitalised in the article title.

Specific guidelines[edit]

Minor planets[edit]

When there is no established common name, all articles about minor planets (with the exception of officially recognized dwarf planets, addressed below) should be titled as follows:

  1. For bodies that have received official naming from the Minor Planet Center (MPC), the article title should be the object's minor planet number (without parentheses), followed by its official name e.g. 4 Vesta.
  2. Where a body has not yet received an official name, but has received a minor planet number, the article title should be the object's official minor planet number in parentheses, followed by the object's provisional designation. This provisional designation is usually the object's discovery year, followed by an alphanumeric code signifying exactly when within the year it was discovered e.g. (15760) 1992 QB1. Any use of the name other than the title should use proper subscripting, using the provided templates {{mp}} and {{mpl}} (e.g. {} yielding (15760) 1992 QB1).
  3. Where a body has neither received an official name nor minor planet number, the article's title should simply be the object's provisional designation as described above, e.g. 2004 JG6 (written {} yielding 2004 JG6).

Unofficial nicknames should not be used as article titles. Official minor-planet names are published in the MPC's Minor Planet Circulars. Diacritical marks should be included in titles. For composite names, however, hyphens should be changed into en-dashes per MOS:ENDASH. Use of straight apostrophes is recommended. This does not include the ʻOkina letter, which should be preserved.

Minor-planet moons[edit]

Titles of these articles should follow underlying titling policy.

Dwarf planets[edit]

When there is no established common name for the subject of the article, the official name should be used for the article title. In situations where there are other notable objects sharing the same name, the disambiguation term "dwarf planet" should be used in parentheses after the name. An example of this would be Eris (dwarf planet). Regardless of the article title, the MPC catalogue number/name designation should be referenced in the lead sentence. Syntax of this is still debated, but should incorporate a link to the minor planet number article.


Many comets have several different names. Articles about comets should be named in the following preference.

  1. For extremely famous comets which have no issues with disambiguation, use the common name, e.g. Halley's Comet. Other well-known comets with no ambiguity should be titled "Comet <name>", e.g. Comet Hyakutake.
  2. Other comets should be referred to by their official designation in the new-style (post-1994) format. This is usually:
    • For numbered periodic comets: its periodic comet number, followed by P/ for still-active comets and D/ for comets which have broken up or been lost, then the name of the discoverer or co-discoverers separated by hyphens (with no space between the forward-slash and the name[s]). e.g. 153P/Ikeya–Zhang
    • For unnumbered comets: P/ for periodic comets, C/ for comets in hyperbolic orbits, D/ for comets which have been destroyed and X/ for comets for which no reliable orbit has been calculated, followed by the year of discovery, then an alphanumeric code which describes when in the year the comet was discovered, then the name in parentheses, e.g. C/2001 Q4 (NEAT)

Note: Comets are named after their discoverer or discoverers, and those people may discover more than one comet, so using the first option above, i.e. "Comet <Name>", may be ambiguous in some circumstances. For example, Comet Hyakutake may refer to C/1995 Y1 (Hyakutake) or C/1996 B2 (Hyakutake), although only the latter became widely known. Care must therefore be taken in using only the first option above, to avoid ambiguity.


Articles on stars should be titled with the following preferences:

  1. If the star has a traditional name that is more widely used than any other name, this name is to be the article's title (e.g. Vega, Sirius, Aldebaran).
  2. If there is no common traditional name, the Bayer designation is to be the article's title (e.g. Alpha Centauri, Delta Capricorni, Upsilon Andromedae).
  3. If there is no Bayer designation, then the Flamsteed designation is to be the article's title (e.g 55 Cancri, 51 Pegasi, 61 Cygni).
  4. If there is no Bayer or Flamsteed designation, then the Draper catalogue number (HD), variable star designation, or Gliese catalogue number (GJ) should be the article's title based on which one is in wider use (e.g. HD 98800, GJ 3021, Gliese 876, R Coronae Borealis, RR Lyrae, V838 Monocerotis),[1] unless an earlier catalogue number is more widely recognised (e.g. Lalande 21185, not HD 95735).
  5. If there are no Bayer, Flamsteed, variable star, Draper, or Gliese designations, then the most widely recognised (other) name is to be the article's title (e.g. GSC 02652-01324, 2M1207), generally a catalogue acronym or abbreviation followed by the catalogue number.

Extrasolar planets[edit]

As per the consensus established at Talk:Extrasolar planet/Naming (also "Kepler-22b" Talk Page), articles on extrasolar planets should be named according to the parent star's article title[2] then the planetary designation (e.g. 51 Pegasi51 Pegasi b). All planetary designations are to be lowercase letters (excluding the planets of PSR B1257+12 and planets announced prior to 1995, which have uppercase letters). Only if the planet is purposely cataloged differently than its parent star (e.g. GSC 02652-01324TrES-1) should the planet article be named differently.

The issue of whether to add a space between the parent star's name and the planetary designation is to be determined by scientific literature references. In most cases, planets named with Bayer, Flamsteed, and or Variable star designation would always have a space, but other designations are debatable. Either way is acceptable, but please use Google Scholar to determine which one is in more use (which in turn should be the article title).

Proper names of exoplanets[edit]

For official exoplanet names which have been through the formal International Astronomical Union (IAU) naming process (starting in 2015), see the common names section above.

Unofficial nicknames which have not been through the IAU naming process (e.g. Bellerophon and Osiris) are not officially recognized, and should not be used. These names are only to be mentioned in the article.


Articles on galaxies should be titled according to the following criteria (in order of preferences):

  1. Traditional name where approved by the International Astronomical Union and where this is widely used in general or professional literature (e.g. the Andromeda Galaxy)
  2. The Messier object number (e.g. Messier 30)
  3. The New General Catalogue number (e.g. NGC 1)
  4. Any relatively unusual catalog name that is widely used in general or professional literature and that is more commonly used than the IC or UGC number (e.g. Arp 220, Mrk 33)
  5. The Index Catalogue number (e.g. IC 2)
  6. The Uppsala General Catalogue number (e.g. UGC 1)
  7. The most commonly used scientific designation given by any other catalog

Note that traditional galaxy names are proper nouns. Therefore, all the words in the galaxy name should begin with capital letters. For example, "Andromeda Galaxy" is acceptable, but "Andromeda galaxy" is not.

Groups and clusters of galaxies[edit]

Articles of groups and clusters of galaxies should be titled according to the following criteria (in order of preference):

  1. Traditional name where approved by the International Astronomical Union and where this is widely used in general or professional literature (e.g. the Local Group, Virgo Cluster, Stephan's Quintet)
  2. Name based on the brightest galaxy in the group when that name is commonly used for identification (e.g. the M81 Group); this is only applicable to groups of galaxies within approximately 50 Mpc
  3. The most commonly-used catalog number (e.g. Abell 3266)

Note that group and cluster names are proper nouns. Therefore, all the words in the galaxy name should begin with capital letters. For example, "Virgo Cluster" is acceptable, but "Virgo cluster" is not.


  1. ^ Entries from the Catalogue of Nearby Stars with identifiers at or above 1,000 are from the Gliese and Jahreiß extensions, so these should use the "GJ" identifier. The "Gliese" designation is appropriate for entries below 1,000.
  2. ^ According to references, the name "HD 160691 b" is in more use over the name "Mu Arae b". But because the consensus for naming star articles require that the star's article be named by its Bayer designation, the planet (in turn) is titled Mu Arae b.

See also[edit]