->''"It is true what they say: Women are from Omicron Persei 7, men are from Omicron Persei 9..."''
-->-- '''Ndnd of the planet Omicron Persei 8''', ''WesternAnimation/{{Futurama}}'', "When Aliens Attack"

In speculative fiction, inhabited planets will often lack a proper name, instead being designated by the name of the star they orbit and a number. It is almost never the case that the star is referred to by a catalogue number. Natural satellites will also often lack proper names and be identified as "the moon of planet X" or somesuch.

In RealLife, notable celestial objects, like the other planets of the solar system, their moons and certain stars easily visible from Earth have had proper names for about as long they have been known to exist (although admittedly some are much better known than others). A large number of lesser objects, such as asteroids and extrasolar planets are assigned catalogue numbers. When extrasolar planets were first discovered in 1995, the astronomical community used lowercase letters instead of numbers (e.g. 51 Pegasi b, 70 Virginis b). While it is reasonable that an interstellar civilisation surveying a star system would initially assign numbers to the planets along the lines of "[=XLL325-1=]" for the first planet of the star [=XLL325=], it would be strange if they failed to come up with proper names for the star and planets (eg. "[[VideoGame/{{Freelancer}} Baltimore]]" instead of "[=XLL325=]") if they decide to colonise the star system. Even sillier is when a planet inhabited by an alien species is given such a label and said inhabitants begin to use that designation themselves. It's sillier still if the species has ''always'' called their own planet by a catalogue number. After all, how many humans in reality or fiction ever refer to our little world as [=Sol III=]?

This trope is arguably justified when the catalogue number is used by TheEmpire to name planets occupied by another species. StarfishAliens may call their planet Krzjdlwsk (which, admittedly, would probably still be pronounceable in some terrestrial language), but stormtroopers trying to pronounce the name may be tempted to just use the catalogue number or come up with a nickname for the planet, like "Krazy Dullwhisk." May sometimes be a case of TranslationConvention.

The trope can also be justified as a naming convention by a bureaucratic or military authority that wishes to come up with a neutral name that does not offend political sensibilities. This sort of thing is common on Earth, as anyone who's visited (London)derry in Northern Ireland or the Persian (Arabian) Gulf can attest. If two competing groups settle a planet, and one calls it Cleveland while the other calls it Cayuga, it might just be best for a visiting starship captain to call it "Rigel VI".



[[folder: Anime and Manga]]
* In ''MagicalGirlLyricalNanoha'' [[InsignificantLittleBluePlanet Earth]] is also "Unadministrated Planet #97" to the Time-Space Administration Bureau. The Bureau categorizes the known worlds into administrated, non-administrated, and uninhabited, and numbers them (possibly) by the time of discovery. Mid-Childa, its homeworld, is "administrated world #1", for instance.
* ''Manga/OutlawStar'' uses this a lot, first with Sentinel [=III=], and later with planets in the Heifong system.
* Non-spatial example: Japan is renamed Area 11 in ''Anime/CodeGeass''.
** This is chiefly a political move by Britannia, as it [[YouAreNumberSix removes the identity]] of the conquered country to make it harder to establish a cause to revolt by.
** Early in the series there's a reference to part of the former Middle East (Saudi Arabia) being referred to as Area 38. Presumably these numbers designate actual places under rule by the Brittanians.
* In the ''Franchise/{{Gundam}}'' series, especially but not exclusively in the Universal Century timeline, [[TheFederation The Earth Federation]] names clusters of its artificial space colonies as "Sides", with the numerical designation of "Side ''x''". For example, Amuro Ray's home cluster was designated as "Side 7".
** Each of the seven Sides has an actual name in addition to its Side number, though these are rarely used for some reason. The names are, in order, "Zarn", "Hatte", "Munzo" (or "Zeon" for most of UC), "Mua", "Loum", "Riah", and "Noa". Individual colonies tend to have both a numerical designation and an individual name (Side 1, Colony 1 is "Shangri-La").
* ''Anime/DragonballZ'' has a minor example in Frieza's conquered planets - they all bear his name (indicating that he owns them), and a numeral, probably to indicate in what order they were obtained. Vegeta recovers on Frieza Planet 79 before heading to Namek. His brother seems to follow a similar practice, as two of his henchmen are said to come from Cooler Planet 98 and Cooler Planet 256.
* ''Anime/LegendOfGalacticHeroes'': Rondolina, a planet which plays an important role in the backstory, was also known as Sirius VI.
* ''Anime/VoicesOfADistantStar'' has Sirius IV.
* ''LightNovel/BodaciousSpacePirates'' has Tau Ceti III (or Uminoakehoshi)

[[folder:Comic Books]]
* Franchise/TheDCU: Talok III, IV, and VIII, Beltair IV, Trigus VIII, Toomey VI.
* The Franchise/MarvelUniverse has Centauri IV, Sirius III-IV, Rigel III, Capella II (whose natives call it Lotiara), Arcturus IV, A-Chiltar III, Ciegrim-7, Horus IV, Maklu IV, Stonus I-V, Tarnax IV, Wundagore II and Power Planet 4.
* ''Primortals'': Achernar III.
* ''ComicBook/LesMondesDAldebaran'' is set on Aldebaran IV (also known simply as Aldebaran).

[[folder:Fan Works]]
* In ''FanFic/AeonNatumEngel'' Earth is classified as ǶǡѬѮӜ-[(zero-46,656) and (thirtyone-1296) and (eleven-36) and (thirtyfive)]-[(zero-60,466,176) and (one-1,679,616) and (twentynine-46,656) and (seven-1296) and (seventeen-36) and (three)]. Would be considered as a case of Exaggeration if not for beings who are using that numbering system, the Migou.
* Planton V from ''Fanfic/CalvinAndHobbesTheSeries''.
* The ''FanFic/GoldenAge'' series has planets Excelsis-One through Five.

* Used occasionally in ''Franchise/StarWars'': Yavin 4 is actually the fourth moon of the planet Yavin, there is also [[Film/TheEmpireStrikesBack Hoth VI]], Aduba-3, Telos IV, Malachor V and so on. However, the vast majority of planets where people actually live (Yavin 4 was just a base, for example) have a proper name, like Naboo, Coruscant, Tatooine and Kamino, although one (possible) exception is "(the Forest Moon of) Endor" where the [[Film/ReturnOfTheJedi Ewoks]] live. Justified because Ewoks are tribals, not a spacefaring race, and have no concept of astrography.
* ''Film/TheChroniclesOfRiddick'' have Helion Prime and then up to Helion Five.
* ''Film/StarTrekIITheWrathOfKhan'''s main plot begins when someone mixes up the planets Ceti Alpha VI and Ceti Alpha V (one of them blew up and the other's orbit was shifted and became a desert wasteland as a result). Whoever forgot to COUNT THE FREAKING NUMBER OF PLANETS when they arrived in the system deserves to have some sort of parasitic worm shoved in their ear...
** In real life, however, Pluto is not always the farthest (dwarf) planet, so when it happens, it's easy to confuse it with Neptune if one doesn't know their masses etc., but only counts objects.
* The planet where both ''Film/{{Alien}}'' and ''Film/{{Aliens}}'' takes place on is called LV-426, though in the latter its also known as [[MeaningfulName Acheron]].
** The third movie has Fiorina 161.
** ''Film/{{Prometheus}}'' is set on LV-223.
* ''Film/EnemyMine'' had Fyrine IV.
* ''Film/ForbiddenPlanet'' is set on Altair-4.
* ''Film/FantasticFour: Rise Of The Silver Surfer'' mentions Rigel III as the previous planet eaten by Galactus.
* ''Film/LostInSpace'': Alpha Prime.
* ''Film/{{Screamers}}'' is set on Sirius 6B.
* In ''Good Boy!'', all dogs are aliens from the planet Sirius VII (the Dog Star, geddit?)

* ''Proxima Centauri'' may be the UrExample, with the planets Centauri I and Centauri II.
* Not uncommon in ''Franchise/TheHitchhikersGuideToTheGalaxy'', sometimes using Greek or Roman letters instead of numbers, for variety. Several planets did have actual names, however: Earth ("What a boring name..."), Magrathea, Golgafrincham, [[strike:Persephone]] Rupert...
* Not usually used in Creator/IsaacAsimov's ''Literature/{{Foundation}}'' series, except for Gamma Andromeda V.
* ''ClansOfTheAlphaneMoon'' has Alpha (Centauri) II and Alpha III M2
* In Creator/LoisMcMasterBujold's ''Literature/VorkosiganSaga'' novels:
** The Cetagandan Empire does this with Greek letters. There are eight planets and they're all "Something Ceta" - Eta Ceta, Rho Ceta, Mu Ceta and so on.
** Cordelia Vorkosgian's homeworld of Beta Colony is technically a numbered homeworld, though Alpha Colony and Gamma Colony have since disappeared. As the name implies, it's very close to Earth in normal space (rather less so via the wormhole network, compared to other planets).
** The planet Kibou-daini means "Hope #2", number sign and all it's a very formal and technical form in Japanese and isn't usually seen out of signs and manuals. This is because there are multiple worlds called "New Hope" or the equivalent, and the two is required to distinguish it from the others.
** There are also more typical examples, like Dagoola IV, or Tau Verde IV.
* ''A Far Sunset'' is set on Altair V. ''As On A Darkling Plain'', by the same author, has Sirius A II, otherwise known as Makta.
* In the ''Franchise/{{Dune}}'' series of novels, the homeworld of the Ixians is called Ix, a mysterious name with a meaning lost to time. One character with "ancestral memories" notes to himself with amusement that "Ix" is merely the name of a numeral from a culture that has long been forgotten by the general population of the present universe. Seemingly implicit is that the planet was originally designated with the number 9, written in Roman Numerals as IX.
** Several other plants have numbers, such as Salusa Secundus, Wallach IX and IV Anbus (pronounced as "four-anbus").
*** [[VideoGame/DuneII The video game]] adds Sigma Draconis IV. The name is totally in character for the House Ordos who live there.
* Creator/RobertAHeinlein's various stories have: Capella VIII, Spica IV, Planet P, Beta Corvi III, Epsilon Gemeni V, Gamma Leonis [=VIb=], Shiva III, Thaf Beta VI, and Thoth IV.
** Tellus Tertius and Tellus Secundus are [[AltumVidetur variations]].
** Justified in ''Literature/HaveSpaceSuitWillTravel'', since Vega V's real name is unpronounceable to humans.
* Creator/ArthurCClarke's ''Literature/TheSongsOfDistantEarth'' has Sirius X.
* ''[=SpaceWreck=]: Ghost Ships And The Derelicts Of Space'' has one story set on Alshain IV.
* Usually averted in ''Literature/HumanxCommonwealth'', the only exception being Tharce IV.
* Creator/StephenKing's ''Literature/TheTommyknockers'' briefly features Altair IV, which may be a reference to ''Forbidden Planet''.
* LV-426, the setting for ''Film/{{Aliens}}'' is named Acheron in the novelisation.
* Although called Literature/{{Darkover}} by the [[LostColony natives]], the Terran Empire's name for the planet is Cottman IV.
* ''Seeds Of Light'': Sirius B III.
* In Creator/HarryTurtledove's ''Literature/{{Worldwar}}'' series, The Race calls their homeworld[[note]]Tau Ceti II[[/note]] Home, and call the other two planets under their rule Rabotev 2[[note]]Epsilon Eridani II[[/note]] and Halless 1[[note]]Epsilon Indi I[[/note]], following the [Star][number] convention. They call their latest target Tosev 3, the third planet from the star Tosev. The Tosevite locals call it Earth.
* Asteroid B612, home to Literature/TheLittlePrince.
* The Literature/ChooseYourOwnAdventure book ''The Third Planet From Altair'': It's right there in the title.
* ''Revolt On Alpha C'': Alpha C(entauri) IV.
* Possibly justified in Creator/StephenBaxter's ''ManifoldSpace''. The Gaijin refer to their homeworld as Zero-zero-zero-zero, indicating it's their "point of origin," but the Gaijin are MechanicalLifeforms who don't have a human-like mode of consciousness.
* The ''Literature/PerryRhodan'' universe has the Arkonides calling their homeworlds Arkon I, II and III. This is quite intentional, since they were moved into an equilateral triangle with the star in its center (they were originally the 2nd to 4th planet). The other planets in the system have names. There are also more traditional examples, like Betelgeuse III and the planets of the Vega system (IX, X, XL)
* In ''Literature/TheHistoryOfTheGalaxy'' series, many secret [[TheEmpire Earth Alliance]] automated bases throughout the galaxy are called "Omicron"+<serial number>. This is likely to hide their locations from enemy spies.
* The ''Literature/AllianceUnion'' universe has Alpha Station, Beta Station, and Omicron Point. Gehenna is also officially known as Zeta Reticuli II.
* In one of the ''Literature/{{Lensman}}'' novels, Tregonsee comments in passing that he thinks of his homeworld as Rigel IV, and only bothers with a more accurate designation if he needs to give astrogation coordinates. This implies that the Rigellians don't have an independent name for their homeworld (but could simply be Lens-related TranslationConvention).
** Some other planets from the series are also named this way, such as Aldebaran I and II, Lyrane II, Thrallis II and IX, Palain VII, and Velantia III.
* In Creator/JackVance's ''Allastor'' stories, the planets of the Allastor Cluster all have numerical designations as well as names, so Allastor 933 is also Marune, planet 2262 is also Trullion, 1716 is Wyst, etc.
** One of Vance's other stories, ''The Book Of Dreams'', has Arcturus IV.
** ''Emphyrio'' has Capella V, although it's also known as Maastricht.
** ''Literature/TheDemonPrinces'' mentions Caph IV, Mizar VI, and Xi Puppis X.
** ''The Last Castle'' has Etamin IX.
** ''Space Opera'' has Phi Orionis II, otherwise known as Zade.
* In Creator/PoulAnderson's ''Literature/TauZero'', the ''Leonora Christine'''s original destination was Beta Virginis III.
* Creator/PhilipKDick's ''Shell Game'' is set on Betelgeuse II.
* Creator/VernorVinge's ''Conquest By Default'': Epsilon Eridani II (otherwise known as Miki).
* In Creator/SergeyLukyanenko's ''Literature/RoughDraft'' and ''FinalDraft'', all parallel worlds have a numerical designation, the origin of which is not known. Our world is Earth 2. Many of the mentioned worlds have proper names, although the numerical designation is used most often. For example, our world is sometimes called Demos, due to the prevalence of democracy. It was initially assumed that there are only about two dozen parallel worlds. However, the number is later revealed to be at least double that (possibly, infinite) with Earth 46.
* Gordon R. Dickinson's ''Literature/ChildeCycle'' has Fomalhaut III, better known as Dorsai.
* Creator/AnneMcCaffrey:
** ''Literature/TheShipWhoSang'': Beta Corvi IV is home to a highly-advanced race of non-humanoid aliens in the chapter "Dramatic Mission".
** ''Literature/TheRowan'' has a character from Deneb VIII.
* Kevin J. Anderson's ''Literature/TheSagaOfSevenSuns'': Paris 3, Qrohna 3, Constantine III, Jonah 12.
* Almost entirely averted in Creator/UrsulaKLeGuin's ''Literature/{{Hainish}}'' novels.
** The exception is Eleven-Soro, which features in only one short story, "Solitude".
** The setting of ''Literature/RocannonsWorld'' was known as Fomalhaut II before being renamed [[spoiler:Rokanan]].
* The Franchise/StarWarsExpandedUniverse generally does this quite realistically--the only planets with numbers are those home to small or recently founded colonies, such as Comkin Five.
* ''Serpent's Reach'': The Majat homeworld is Alpha Hydri III (although the Majat call it Cerdin).
* Creator/StanislawLem's ''The Invincible'': Regis III. It's the human name - the natives [[spoiler: probably called it something else, but came down with a bad case of extinct.]]
* ''Tauf Aleph'' has Tau Ceti IV.
* In one of the ''Literature/SoulDrinkers'' novels, an [[TabletopGame/{{Warhammer 40000}} Adeptus Mechanicus]] world is referred to solely by a "serial number"-type name. Of course, given the nature of that particular branch of the Imperial hierarchy, that's about par for the course.
* The ''Literature/HyperionCantos'' have variations with [[GratuitousGerman Deneb Drei and Deneb Vier]], [[AltumVidetur Sol Draconi Septem]], and Vitus-Gray-Balianus B.
* Creator/DavidWeber's ''Literature/TheApocalypseTroll'': Sigma Draconis IV.
* ''City At World's End'': Vega IV.
* ''The War Against The Rull'': Eristan II and Mira XXIII.
* Creator/CordwainerSmith's ''The Dead Lady Of Clown Town'' (part of the ''Instrumentality'' series): Fomalhaut III.
* Robert J. Sawyer's ''Calculating God'' has Groombridge 1618 III.
* ''The Winds Of Altair'' is set on Altair VI.
* All planets mentioned in ''Way Station'' are named this way: Thuban VI, Polaris VII, Mizar X, Vega XXI, Enif V, Alphard XX, etc. So not only are all the space-faring aliens in this region of the galaxy conveniently from star systems humans have names for, but they also seem to have no other names for their homeworlds, and no names for themselves besides "Thubans" and "Vegans". (Although to be fair, Earth is also referred to as Sol III.)
* ''Total Eclipse'' features Sigma Draconis III.
* ''Unearthly Neighbours'': Sirius A IX.
* Planet #666 from ''[[Film/JasonX Jason X: Plane of the Beast]]''.
* Planets in the ''Literature/StarCarrier'' series use this for the purpose of navigation. Inhabited planets are given local names that are used interchangeably with the star-number name. For example, the planet visited in ''Earth Strike'' is named both Eta Boötis IV and Al Haris al Sama ("Guardian of Heaven" in Arabic).
* Standard procedure for Obin-controlled planets in ''Literature/OldMansWar'', due to their CreativeSterility and [[EmptyShell lack of individual identity]]. Despite the trope name, their homeworld Obinur is the one exception, although its name is basically the Obin equivalent of humans calling Earth "home of humans".

[[folder: Live Action TV]]
* ''Franchise/StarTrek'':
** ''Series/StarTrekTheOriginalSeries''. Just a few of the many examples:
*** The planets in the Rigel system: various episodes mention 2, 3, 4, 5, 7, 10 and 12.
*** Other commonly mentioned systems include Altair (III, IV, VI), Deneb (IV, V) and Tau Ceti (III, IV, Prime)
*** The Sigma Draconis system ("[[Recap/StarTrekS3E1SpocksBrain Spock's Brain]]") has nine planets and mentions numbers 3, 4, 6 and 7.
*** Aldebaran III in "The Deadly Years."
*** Alpha Carinae II ("The Ultimate Computer") and V ("Wolf in the Fold").
*** Archer IV is an odd example, seeing as it's in the 61 Ursae Majoris system.
*** Plenty more where that came from: Acamar III, Beta Aquilae II, Taurus II, Canopus III, Gamma Trianguli VI, Mintaka III, Omicron Ceti III, Dytallix B, Mizar II, Pollux IV, Procyon V, Sirius IX, Tau Cygni V, Vega IX...and those are just the ones orbiting real stars!
** At least some of these can be {{handwaved}} by the fact that the natives (if there are any) may have their own names for said planets. Others... not so much.
** ''Series/StarTrekTheNextGeneration'' had the episode "First Contact" (not to be confused with the movie), featuring a previously uncontacted race who believed that they were a higher species and their planet was the center of the universe, but they called it by the Federation name of Malcor III (justified by [[TranslationConvention the near-Omnipotent universal translator]]).
** The Cardassian homeworld is called "Cardassia Prime." Other planets in the Cardassian system are numbered. Planets in the Bajoran system also have numbers, but the homeworld itself is simply "Bajor."
** According to the book ''Star Charts'', Andor/Andoria orbits Procyon VIII.
** Not to mention all the places called Starbase [Number] or Earth Colony [Letter-Number].
** It seems that the stars have names and the planets are ordered by the distance from the sun. But nobody ever calls Earth "Sol 3."
* Most or all planets in ''Series/StargateSG1'' were numbered, although many had proper names as well. Earth has one as well: [=P2X-3YZ=]
** They were generally pretty good about this trope, though. When they encountered an inhabited planet, they usually switched from the catalogue number to whatever the natives call it. Of course, the characters did manage to remember offhand the catalogue numbers for many of their mission destinations even years later.
*** Carter mentions in one episode that the designation is "based on a binary code the computer uses for extrapolation," so it's some kind of a mathematical formula produced by the Earth-based dialing computer to pinpoint location in space. It would ''seem'' that the first digit may indicate galaxy, since every Milky Way address seems to begin with "P," while every Pegasus address seems to begin with "M" (in spite of common sense suggesting it should be the other way around).
*** The "P" in all probability comes from "planet"; "M" might've been chosen with the intent to have most of the Pegasus worlds be moons. The P = planet, M = moon is likely exemplified by [[http://stargate.wikia.com/wiki/M4C-862 M4C-862]], which is in the Milky Way, but referred to many times as a moon.
** {{Lampshade|Hanging}}d in a first-season episode of ''Atlantis'', where after having to be reminded what planet a particular code corresponded to, Ford asked why they couldn't simply give descriptive names to the planets like "Planet Waterfall".
*** Interestingly, that's a rarity. Planets are almost always referenced by their computer designations, and you never, ever hear "P3 what?!" "The one with [[RecycledSet all the trees]]." "Oh." or anything like that except for this one occasion. Even characters who are not supposed to be geniuses like Carter will always remember a planet by its designation, and the listener will have no trouble.
* ''Series/PowerRangersInSpace'': Andros's homeworld is "KO-35" and referred to as a colony. It's in the "Kerovan system." That... doesn't actually give a proper name to Andros' people ''or'' their world. Fans speculate that the planet it's a colony of (which is, by the way, only suggested to exist by FridgeLogic - for KO-35 to be "the space colony" there ''must'' be an original civilization... and that's all we got.) must have a proper name. They seem to just consider themselves humans. When the Rangers first meet [[HumanAliens Andros]] (and discover that he's not a alien) he mentions that "Earth isn't the only place where humans live." This is never explained, however people from KO-35 are indistinguishable from people on Earth and the only known difference is that they have mild telekinesis (which Andros claims is a learned ability, not a genetic one).
* ''Series/BabylonFive'':
** It's mostly only colony worlds that retain numbered designations: Epsilon 3, Proxima 3, Deneb IV, Vega 7, Orion 4, Orion 7, or the disputed Centauri colony at Ragesh 3. The only exception is the name of Centauri Prime, but it's possible that this is a back-designation and there's a "New Centauri" somewhere in the Centauri Republic. Minbar is also known to humans as Chi Draconis VII.
** The Centauri claimed that they thought Earth was a LostColony at first contact due to "clerical error:"
--> ''Londo: We thought your world was Beta 9, actually it was Beta 12''
* From ''Series/{{Lexx}}'', a ''literal'' numbered homeworld: Brunnis-2 is where all the inhabitants of Brunnis settled after abandoning their original star system (and universe).
** Also spoofed with the unreachable PleasurePlanet "[[StealthPun Nimbus IX]]."
** Stan is from Ostral-B which seems to be similar to this, and Zev/Xev was from "[=B3K=]".
* In ''Series/DoctorWho'' Earth has occasionally (such as in "Last of the Time Lords") been identified as "Sol 3" from outside sources.
** The audio play ''The Ultimate Adventure'' involves the planet Altair III.
* ''Series/BlakesSeven'' had many of these, like Altern V, Beta V, Mecron II, Zeigler V, Zolat IV, Gauda Prime, Porthia Major, Magdalen Alpha, Del-10, K-14, PK-118, XK-72, and Star One.
* ''Series/BuckRogersInTheTwentyFifthCentury'': Aldebaran II, Altair V, Iris VII.
* ''Series/SpaceAboveAndBeyond'' refers to Chig planets as things like 2063F and 2064R, while human colonies have proper names.
* ''Series/{{Fireball XL5}}'' simply numbered planets: Planet 46, Planet 72, Planet 83, etc.
* In ''Alpha Scorpio'', the aliens come from Antares V.

* ''Commander Perkins: The Vega Series'' has Vega VIII.
* ''Radio/TheSpaceGypsyAdventures'' has the Galvert system with at least seven inhabited planets differentiated simply by number. Detective Constable Bones is from Galvert VI (whose inhabitants, Bones included, all speak with suspiciously [[UsefulNotes/BritishAccents Welsh sounding accents]]), but the characters visit several other worlds in the system. Other planets such as Zenophon aren't numbered.

[[folder: Tabletop Games]]
* ''TabletopGame/{{Traveller}}'' uses arbitrary numbers for the least important systems. For example, here's a map centered on [[http://www.travellermap.com/?x=-111.284&y=40.5&scale=64&options=887&style=poster 876-574]]. (More important systems will more usually be known by the name of their most important habitation, be it artifact, planet, moon, or asteroid belt.)
* ''TabletopGame/{{Warhammer 40000}}'' uses names like Lorne V and Kaurava IV on top of more standard titles. But they also tend to name a star system after its most important planet, a subsector after its most important system...
* ''TabletopGame/EmpireOfThePetalThrone'' Tékumel was previously known as Nu Ophiuchi d or Sinistra d.

[[folder: Video Games]]
* ''Franchise/{{Metroid}}'':
** Tallon IV, although it's sort of confusing in ''VideoGame/MetroidPrime''. There's a room that gives you a holographic display of the solar system. Tallon IV is actually the fifth planet in that system and the system itself is called the Ooromine System. There is an Ooromine II, but the other planets have distinctive names. This includes Zebes (the planet of the original ''Metroid'' and ''Super Metroid''), Billium and Twin Tabula.
** The Metroid home planet is [=SR388=]. Justified as the name is a catalog name given by the Federation. The planet was never colonised by them (due to certain nasty energy-sucking jellyfish-things) and so there's no reason for a proper name. Samus' own home colony is [=K2-L=].
* The second ''Franchise/AlienVsPredator'' game takes place upon LV-1201.
* ''VideoGame/EveOnline'':
** Every planet and moon is numbered. Only planets in the homeworld systems of Amarr, New Caldari, Luminaire, and Pator, get proper names.
** Furthermore, the systems not controlled by the {{N|onPlayerCharacter}}PC empires all have numeric designations like [=B-VIP9=]. There have been proposals to name some of these systems after characters whose players died in real life.
** Additionally, systems in wormhole space have numerical system, constellation and region designations, with the exception of one planet named after a well-known Icelandic volcano.
* ''VideoGame/EndlessSpace'' uses it. Even your empire's homeworld is literally a numbered homeworld. Ironically, a later patch added ONE properly-named planet to the game... Auriga, which isn't a homeworld to any of the established factions, but IS the planet where ''VideoGame/DungeonOfTheEndless'' and ''VideoGame/EndlessLegend'' took place.
* ''VideoGame/EndlessSpace2'' gives each empire's starting planet a unique name, averting this trope. It goes further by giving players the option to rename any planet they colonize, meaning you could have an entire empire of unique planets if you so choose.
* ''VideoGame/{{Starbound}}'' plans on this with the star name, then the number with Roman numerals and then moons around said planets are given alphabetical designations in order of closest to farthest. One example could be Alpha Nu Aql Majoris III b. The player's homeworld, however, can be named.
* This trope exists in the ''Franchise/{{Halo}}'' universe with planets like Chi Ceti 4, Eridanus II, Charybdis IX, Epsilon Eridani IV, Draco III, Paris IV, Circinius IV, and Sigma Octanus IV. There are also a few numbered planets that ''aren't'' named after the star they orbit, like Beta Gabriel and Jericho VII.
* In the [[FourX 4X]] game ''[[VideoGame/GalacticCivilizations Galactic Civilizations II]]'' the homeworlds of the various species and the other planets in the same system have proper names. Other systems with no native intelligent species however have planets with Star Name + Number. The player is free to rename them though when colonized.
** Minor races have their planets named after them. Some, like the Dark Yor, even have their own solar system (following the standard naming convention for the various planets).
** The campaign maps usually have a few planets with unique names.
* The ''Franchise/StarOcean'' series uses both this and proper names for planets. For example Earth is also known as Sol III while [[VideoGame/StarOceanTheSecondStory Expel]] is also known as Arcura IV.
* The second and third ''VideoGame/MasterOfOrion'' games all have numbered planets. You can name the star though, so you can settle on Trope IV.
* In ''VideoGame/{{Xenosaga}}'' all of the capitals of Galaxy Federation have been named _th Jerusalem, with Earth being named Lost Jerusalem, and the capital during the game's events Fifth Jerusalem.
** There's also the planet of Second Miltia, suggesting that other planets are numbered in this way.
* By default, ''VideoGame/{{Outpost 2}}'' names the planets in this way while using the names of real stars, resulting in planet names like "Sigma Draconis I" or "Delta Pavonis II." You can, however, rename the planet to your liking, and ''Outpost 2'' simply calls the planet "New Terra."
* ''VideoGame/FreeSpace'' has Altair V, Cygnus Prime, Deneb II, and Deneb III.
* ''VideoGame/SystemShock 2'' is set around Tau Ceti V.
* Averted in ''Franchise/MassEffect''. Most planets and solar systems that you visit in the game have already been explored by someone, and as such already have names associated with them. Even lifeless rocks in distant nebulae have names. Some come from human mythology and history, but most have been named by the various alien races that have already been established in the galaxy for millennia. The only exceptions are 2175 Aeia and 2175 [=AR2=], never formally explored and thus never given a name beyond the scientific designation.
** The very first planet ever visited in the series has the designation Eden Prime, even though no other Eden planets are ever encountered. The name is most likely symbolic. In the Bible, Eden was the first terrestrial human settlement and was a paradise until the humans got kicked out. In the game, Eden Prime was one of the first extra-terrestrial human settlements and was a paradise... [[spoiler: until the geth invaded]]. (This plays on the mathematical notion of "prime", e.g. ''f'(x)'' is the first derivative of ''f(x)'').
* ''VideoGame/{{Marathon}}'' is set around Tau Ceti IV.
* ''Franchise/DeadSpace'' has Aegis VII.
* In ''Franchise/StarTrek: Birth Of The Federation'', nearly all planets follow the trope. Earth and the Solar System planets are the exception. Interestingly, the first planet in a system is always called <star name> + "Prime". The rest attach Roman numerals. Cardassia Prime is the exception, as it is normally the second planet in the system, and the ''first'' planet is named Cardassia II.
** ''Star Trek: Bridge Commander'' starts with the destruction of Vesuvi III.
* In ''VideoGame/{{Spore}}'', catalogue numbers are reserved for anomalies like black holes; every star or binary system has a name. Planets, however, including homeworlds, are designated using the name of the star or binary system followed by a number, except for the player homeworlds, which are named when you first start a game on that world.
* ''VideoGame/{{Freelancer}}'' gives the sparsely populated Border Worlds names like "Sigma-14" and "Tau-23," while those under house authority are named after places on Earth, such as "New London" or "Frankfurt."
* It doesn't matter if it's your homeworld. In ''VideoGame/SpaceEmpires'' it'll still be called "[[ShoutOut Wolf]] [[Series/StarTrekTheNextGeneration 359]] VIII".
* In ''VideoGame/StarControlII'', planets are referred to as the name of the star plus a number (such as Procyon II, Alpha Tauri I, Gamma Kruger III, Eta Vulpecolae VI, Arcturus V, Beta Orionis II...). Aliens do have names for their homeworlds (e.g. Spathiwa, Kyabetsu, Syra, Fahz, Vlik, Falayalaralfali), but they will often use the standard name in conversation, presumably because it makes them easier to find.
* In ''VideoGame/{{Ascendancy}}'', the player can name their colonies whatever they want, but the defaults are (Starname) (Roman numeral) (such as Hope II, Nougat IV, etc.)
* Several planets in ''VideoGame/SupremeCommander'' are named this way.
* ''Rigel's Revenge'': Rigel V.
* ''[=AltairVI=]'': It's right there in the title.
* ''VideoGame/SpaceQuest'', being a parody game series (the latter ones specifically parody ''Franchise/StarTrek'') play this trope to the fullest. The gameplay of the sixth game starts on planet Polysorbate LX. Of course, one has to wonder what sort of life is possible on the ''60-th'' planet in a star system. Actually, not much of a life. The place is a dump. And yet [[TheCaptain Captain]] [[CatFolk Kielbasa]] has chosen it for shore leave of the crew of the SCS ''[=DeepShip=] 86''. There are also planets Commodore LXIV, Delta Burksilon V, Klorox II, etc. Other planets seem to have proper names, though (e.g. Xenon, Kerona, Pestulon, Estros, [[{{Pun}} Kiz Urazgubi]], Gingivitis).
* Used regularly in the ''VideoGame/WingCommander'' series. Locanda II, Loki IV[[note]]which is also given as the system name on the galaxy map that came with ''Prophecy'', presumably an error by the graphics artist(s) involved[[/note]], and Mylon II come up as plot points.
* ''VideoGame/NoMansSky'': If it's not [[APlanetNamedZok named "Zok"]] or based on the conventions of NamingYourColonyWorld, then a planet will follow this convention. (It's taken UpToEleven as well--not only are there planets that follow this convention, but ''whole star systems'' do, too.) Examples include Usnusven II, Quidar II, Daiman IX, Noyade IX, Spekira II, Oria V, Ahktun VII, Soleth Prime, [[Film/{{Aliens}} LV-426]], Hx III, Darko IX, Utwarzers XI, and Vesta Prime. Sometimes can be invoked by players themselves as they keep track of where they've been and encountered Atlas Stations.
* In ''VideoGame/{{Stellaris}}'' uninhabited planets are numbered, moons have their primary's number plus a lowercase letter, but when colonized (or discovered to host a pre-FTL species) they are renamed with either a suggestion based on your empire's chosen naming convention, or something entered by the player. However, if you put a number of some other numerical designation in your homeworld's name the AI will suggest similar names[[note]]for instance, calling your homeworld [System Name]Prime will get your first colony in a system a similar name, while the second colony in a given system will be [System Name]Secundus and a third would be Tertius.[[/note]]
* ''Videogame/EliteDangerous'', all but a handful of the billions of stars are numbered (either randomly generated, or pulled from a astronomical catalog), giving us beautiful names like "Eol Prou RS-T D3-94". Planets share the name of the star they orbit, and are assigned an alphanumeric code based on their orbit. Only a handful of planets or stars have an actual name; some are from previous games or are actually named in real life (such as "Sirius"), and a handful were named by kickstarter backers such as the infamous "Stapled Peacock Flesh", a terraformed Earth-like world.

* In ''Webcomic/{{Zap}}'', "Stickles" (an alien race) come from Stickbat 7. The number isn't because it is the seventh planet from the star, but because they've [[MikeNelsonDestroyerOfWorlds accidentally destroyed six other homeworlds]] in crazy experiments. As one stickle said, "[the other planets] were too flammable."
* In the Punyverse from ''Webcomic/SluggyFreelance'' this seems to be standard practice, with planets named things like Grittania-3 or Chau-5.
* Parodied in ''Webcomic/{{Starslip}}'' when Vanderbeam visits the planet Oculus IV, which inhabited by a race of blind aliens. Once Vanderbeam comments on the "irony", his host replies that there is none since only humans call the planet Oculus IV (they call it "J'tlz'kr") and that he's tired of [[NeverHeardThatOneBefore every single human visitor bringing up the same observation]].

[[folder:Web Original]]
* In ''Literature/ThePentagonWar'', the main planet of the Sirius system is named "America" by its inhabitants. Outsiders still refer to it as Sirius A IV, though.

[[folder: Western Animation]]
* Creator/HannaBarbera's ''Galaxy Trio'' did this a lot.
* Kang and Kodos from ''WesternAnimation/TheSimpsons'' {{Halloween Episode}}s come from the faraway planet of Rigel VII (also called Rigel IV in some earlier episodes).
* Some ''Franchise/{{Transformers}}'' continuities have: Delta Pavonis IV, Rigel III, Rigel 6, Centaris Seven, Ceti Alpha Seven, Deneb IV, Hydrus Four, Floron 3, Daffodil II, Kaiba-5, Regalis V, Regulon Four, Talos Four, Taros Four, Planet Q, LV-117, Gorlam Prime, and Planet X.
* ''WesternAnimation/JusticeLeague'' mentions Rigel IX.
* The Planet X is homaged in the animated sci-fi spoof ''WesternAnimation/DuckDodgersInTheTwentyFourthAndAHalfCentury'' and the Captain Proton holoprogram (based on ''Film/{{Flash Gordon|Serial}}''-type sci-fi) in ''Series/StarTrekVoyager''.
* As quoted above, in ''WesternAnimation/{{Futurama}}'' the Omicronians call their home planet "Omicron Persei VIII." This is a "Numbered" Star as well as a numbered homeworld. Omicron Persei just means the 15th brightest star in the constellation Perseus as seen from Earth, and it's [[http://en.wikipedia.org/wiki/Omicron_Persei a real star.]]
** And when finding out what life would be like if it were a video game, it turns out the VideoGame/SpaceInvaders were from the planet Creator/{{Nintend|o}}u [[UsefulNotes/{{Nintendo 64}} LXIV]].
** In fact almost ''every'' planet in Futurama is named this way. Thuban IX, Amphibios IX, Decapod X, Chapek IX, Dogdoo VII, Tweenis XII. there are few exceptions.
** Further lampooned and played completely straight during the second second Brain Spawn episode.
---> '''Infosphere Brain:''' "Clarification request. Are you the Philip J. Fry from Earth, or the Philip J. Fry from Hovering Squid World 97A?"
---> '''Brainspawn:''' "Earth, you fat idiot."
* In ''WesternAnimation/CaptainStar'', planets are named after the captain who discovered them, with the eponymous Captain Star holding the record.
* In ''Franchise/Ben10'', the home planet of [[ExtremeOmnivore the Gourmands]] (Upchuck's species) is called Peptos XI. There's a very good reason for this, though. It's because when their planet is threatened with invasion, they eat it and use it as fuel to burp-propel themselves to a new one.

[[folder: Real Life]]
* It has been pointed out that if a real person/alien came forward and claimed to be from a planet around a star with a recognizable name like "Arcturus" or "Vega" the claim could easily be considered to be suspicious right off the bat. It's not just that they're using our name while speaking our language (after all, when was the last time somebody told you, in English, that they're from '[[UsefulNotes/{{Germany}} Deutschland]]', '[[UsefulNotes/{{Russia}} Rosseeya]]' or '[[UsefulNotes/{{Japan}} Nippon]]?'), it's that there are literally [[Creator/CarlSagan billions and billions]] of stars, and the chances of an alien just happening to be from one of the only ''one hundred or so'' recognizable stars we have names for is a pretty astronomically small chance. Bright stars are not only outnumbered by smaller, dimmer stars by a long shot (our own sun isn't particularly bright itself, being in the upper-middle range), and just because a star is bright to us in the sky doesn't mean it's close to us, either.
** Highly luminous stars burn out relatively quickly (a few tens or hundreds of millions of years rather than the ten-billion-year life of a star like Earth's sun), making them poor candidates for inhabited planets. For example, Vega (which is still considered a ''low-mass'' star, at about 214% of the Sun's mass, despite being about 40 times as bright) should start evolving into a red giant at an age of roughly one billion years. It's currently about half that age, which is young enough that it's suspected to still be in the late stages of forming planets.
** Someone using one of those neat-sounding star names is probably invoking RuleOfCool.
* A variation of this: the first Earth-like exoplanet to be discovered within its star Goldilocks Zone is named Gliese 581 ''g'', also known as Zarmina's World. This is actually standard naming procedure for exoplanets in the IAU. Basically, each exoplanet discovered has been named (star name) + (lower case letter). The key difference from typical science fiction convention is that they use letters instead of numbers and that the letter corresponds to order of discovery, rather than distance from the star. For example, Gliese 581 g is not the sixth planet from its star (which we can't know for certain at this point anyway) but rather the sixth planet ''discovered'' in the system. It's actually the closest (we know of) to its star.[[note]]Or rather ''was'', since its existence has been called into question.[[/note]]
* Earth would be called "Sol-3" if we didn't live on it. Officially, we could also call it Sol b since it's the first planet ''we'' discovered.[[note]]Scientists ''can'' count: the first object discovered in a system is the star itself.[[/note]]
* The use of Roman Numerals combined with the parent satellite was largely a convention of naming moons(e.g. Europa would be known as Jupiter II).
* Inverted with the decision of the Internationa Astronomical Union to give names voted by the public to some exoplanets and even their stars, that were before known by catalog numbers, such as [[https://en.wikipedia.org/wiki/Mu_Arae Mu Arae]] or [[https://en.wikipedia.org/wiki/55_Cancri 55 Cancri A]] just to name two[[/folder]]