Source / pinned edition

Definition of a Planet in the Solar System; Pluto

Source of package iau.planet_definition · IAU XXVIth General Assembly (Prague, 2006), Resolutions B5 and B6

work: urn:iau:clir:planet-definition#IAU_GA26_PLANET_DEFINITION
number: IAU XXVIth General Assembly (Prague, 2006), Resolutions B5 and B6
kind: urn:iau:clir:planet-definition#resolution

English text of Resolutions B5 and B6, XXVIth General Assembly

edition: urn:iau:clir:planet-definition#IAU_GA26_B5_B6_EN
language: en
officiality: official
materialisation: PINNED_UNOFFICIAL_COPY
life cycle: adopted: 2006-08-24

Publications

URI	Type	documentHash	Retrieved
https://iauarchive.eso.org/static/resolutions/Resolution_GA26-5-6.pdf	text/plain; charset=utf-8	sha256:bfef2e3f62820cb0dd7ea99c9b3daaab9bd1c520141a08cdeba7f05ed0c96f30	2026-08-31T00:00:00Z

Fragments — 19

resolution/B5/footnote/1 · note · referenced by: 2

en · official · sha256:38f61e8a0bb8e47e0594608523796f2f1275f34e5df39926f6669b22ad959902

1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Referencing norms: FootnoteOneNamesThePlanets, named_in_footnote_one

resolution/B5/footnote/2 · note · referenced by: 4

en · official · sha256:83994c05b0238d714263cf585a35203e1443de58c5db28c5af40f8f3e2a23559

2 An IAU process will be established to assign borderline objects to the dwarf planet or to another category.

Referencing norms: BorderlineCategoryByIAUProcess, assigned_category, assigned_category/external, borderline_body

resolution/B5/footnote/3 · note

en · official · sha256:056e04e8a220d0ab406935dde290f438407f32a367a7f0926f428d132b902d7f

3 These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs),comets, and other small bodies.

resolution/B5/heading · heading

en · official · sha256:8cfd03ce02e669c3803fde0e1067811781001854f814c3005a04db08ae9016e2

RESOLUTION B5 Definition of a Planet in the Solar System

resolution/B5/1/a · subpoint · referenced by: 3

en · official · sha256:d7608898120d2ff020adda6a9e0856cd435c572f04c59ff98adc7f193b1c3be1

(a) is in orbit around the Sun,

Referencing norms: orbits_sun, planet, planet/rule

resolution/B5/1/b · subpoint · referenced by: 5

en · official · sha256:a5a5ce7e1a154b3ebfb4d97da6f34497b99d370da8df0fe5bde0a75980d2cf06

(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and

Referencing norms: hydrostatic_equilibrium, planet, planet/rule, small_solar_system_body, small_solar_system_body/rule

resolution/B5/1/c · subpoint · referenced by: 3

en · official · sha256:9c7262322bb6d84c41da12d38ad70ce171f5ad1f8ec1db013e1876a60bdf1eec

(c) has cleared the neighbourhood around its orbit.

Referencing norms: cleared_neighbourhood, planet, planet/rule

resolution/B5/1 · point · referenced by: 3

en · official · sha256:ad644bc2b55e6a7d94784aa5ffee4974485e7f524ad560979e7db2c042827099

(1) A planet 1 is a celestial body that

Referencing norms: CategoryOfPlanet, planet, planet/rule

resolution/B5/2/a · subpoint · referenced by: 3

en · official · sha256:d7608898120d2ff020adda6a9e0856cd435c572f04c59ff98adc7f193b1c3be1

(a) is in orbit around the Sun,

Referencing norms: dwarf_planet, dwarf_planet/rule, orbits_sun

resolution/B5/2/b · subpoint · referenced by: 4

en · official · sha256:303390395773d232d1d240efedafdb4dedc3dadf187c716def1d08c005b6acc9

(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape 2 ,

Referencing norms: borderline_body, dwarf_planet, dwarf_planet/rule, hydrostatic_equilibrium

resolution/B5/2/c · subpoint · referenced by: 3

en · official · sha256:1def76ad62b6b5b6f14fe298c845fa5c096eaa43ba6be342bca6432beeb5f1d6

(c) has not cleared the neighbourhood around its orbit, and

Referencing norms: cleared_neighbourhood, dwarf_planet, dwarf_planet/rule

resolution/B5/2/d · subpoint · referenced by: 3

en · official · sha256:b99021fac4ac71502f48bdd5f009415a835cd519a500115c84f6e4f0d608d2ba

(d) is not a satellite.

Referencing norms: dwarf_planet, dwarf_planet/rule, is_satellite

resolution/B5/2 · point · referenced by: 3

en · official · sha256:9ba9617a4c973122f7d1af6cae2b607b255ae4284e911b12de92448110441ae8

(2) A "dwarf planet" is a celestial body that

Referencing norms: CategoryOfDwarfPlanet, dwarf_planet, dwarf_planet/rule

resolution/B5/3 · point · referenced by: 4

en · official · sha256:79e320d67abba5c276f7a8db8035f9c8cfc5082b71409b4d20e1068378ded86c

(3) All other objects 3 ,except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

Referencing norms: CategoryOfSmallBody, SatelliteOutsideDivision, small_solar_system_body, small_solar_system_body/rule

resolution/B5/preamble · preamble

en · official · sha256:4fa723ebf1784b4ebba9cde8acc6789444ae594936de0c862b5c96771a7b87c4

Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particular, to the designation "planets". The word "planet" originally described "wanderers" that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently available scientific information.

resolution/B5/resolves · provision · referenced by: 2

en · official · sha256:a069c00ef262984ee755ae11897ee5d1e77759ceebeb3c64e4ae5d8f06a0d876

The IAU therefore resolves that planets and other bodies, except satellites, in our Solar System be defined into three distinct categories in the following way:

Referencing norms: SatelliteOutsideDivision, is_satellite

resolution/B6/footnote/1 · note

en · official · sha256:7fa08f6a7aea07f29433447d051617490ad909a328cd1d37022d9dbb5f5e6934

1 An IAU process will be established to select a name for this category.

resolution/B6/heading · heading

en · official · sha256:a98c7c352cfd4189390020ecbf30f039e1e30708a088f146933affd1c37aa38c

RESOLUTION B6 Pluto

resolution/B6/text · provision · referenced by: 1

en · official · sha256:cb093de9edbbab9b5247fdcf8f2f8ee7db3a5f190fba12599ed318f3af2a339a

The IAU further resolves: Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of Trans-Neptunian Objects 1 .

Referencing norms: prototype_of_new_tno_category

Texte français des Résolutions 5 et 6, XXVIe Assemblée générale

edition: urn:iau:clir:planet-definition#IAU_GA26_B5_B6_FR
language: fr
officiality: official
materialisation: PINNED_UNOFFICIAL_COPY
life cycle: adopted: 2006-08-24

Publications

URI	Type	documentHash	Retrieved
https://iauarchive.eso.org/static/resolutions/Resolution_GA26-5-6_French.pdf	text/plain; charset=utf-8	sha256:615e9ad4d3cca189fe966902da5773c65d47b83cd8925e4af1828c940475b8fc	2026-08-31T00:00:00Z

Fragments — 19

resolution/5-6/heading · heading

fr · official · sha256:f8deb405af4f16c927295391365bb7a1d1b90d13f645533e057aec89f7960ef4FR

RESOLUTIONS 5 et 6

resolution/5/footnote/1 · note

fr · official · sha256:938675745e8bff4403d0a279189ce406bacd0e46de9eafc426f5af6e830abe23FR

1 Les 8 planètes sont: Mercure, Vénus, la Terre, Mars, Jupiter, Saturne, Uranus et Neptune.

resolution/5/footnote/2 · note

fr · official · sha256:31bf10c31d7207ead0ba3b1ca31705521a129a67bdbf9073ca6f5b4291ff5e75FR

2. Une action spécifique sera organisée par l’U.A.I. pour décider à quelle catégorie, planète naine et/ou autres classes, appartiennent les cas limites.

resolution/5/footnote/3 · note

fr · official · sha256:6ea8050f06bfa8ea7749e67a0737fea5ca30db465a28e8a7de247501e72e4aa2FR

3. Ceci inclut la plupart des astéroïdes du Système Solaire, la plupart des objets trans- neptuniens (O.T.N.), les comètes et tous les autres corps.

resolution/5/heading · heading

fr · official · sha256:d58d4c9100c204cd6c74998b87af313849f00adb11df44c1019d24697fae0b1fFR

RESOLUTION 5: Définition d’une Planète dans le Système Solaire

resolution/5/1/a · subpoint

fr · official · sha256:51a6a29b4de18eec351c71e8250ff1ef4da1ea27e20de788ade60ae7ff401eceFR

(a) est en orbite autour du Soleil,

resolution/5/1/b · subpoint

fr · official · sha256:485bcfd4161364bb7c7e838d9250334bc82e17bc21204ca5349caea536beac85FR

(b) a une masse suffisante pour que sa gravité l’emporte sur les forces de cohésion du corps solide et le maintienne en équilibre hydrostatique, sous une forme presque sphérique,

resolution/5/1/c · subpoint

fr · official · sha256:a007f9ff415e7eb661975c52bd6ed9bb7577375ade158a5e1489ed1a70bd4feaFR

(c) a éliminé tout corps susceptible de se déplacer sur une orbite proche.

resolution/5/1 · point

fr · official · sha256:cdd2c616683c7d6811224f0623366232870c8964e1fa623e432091cfe41c2553FR

(1) une planète1 est un corps céleste qui

resolution/5/2/a · subpoint

fr · official · sha256:51a6a29b4de18eec351c71e8250ff1ef4da1ea27e20de788ade60ae7ff401eceFR

(a) est en orbite autour du Soleil,

resolution/5/2/b · subpoint

fr · official · sha256:ecfbcdcc20e9064aba0fa842a9179609a3643a7fe0b352200a30265a748156d5FR

(b) a une masse suffisante pour que sa gravité l’emporte sur les forces de cohésion du corps solide et le maintienne en équilibre hydrostatique, sous une forme2 presque sphérique,

resolution/5/2/c · subpoint

fr · official · sha256:bd3d7b1a8c0e48d121d3cad80796bedb7e667990297f005e6920ad555b9e1b6aFR

(c) n’a pas éliminé tout corps susceptible de se déplacer sur une orbite proche,

resolution/5/2/d · subpoint

fr · official · sha256:8d3553d7deb3535bec66ddc2e8ae21209709dc38cb98c499f18bc0c5be32d038FR

(d) n’est pas un satellite.

resolution/5/2 · point

fr · official · sha256:fa55ed488e1196e9414adeeeaa0de44b15861f69a2c7fd5042c61106a3268207FR

(2) une "planète naine" est un corps céleste qui

resolution/5/3 · point

fr · official · sha256:d2b372ecd50f047bd5662bdebba904704be66d41c3ad8f8dca20f7b0aac02956FR

(3) tous les autres objets3 en orbite autour du Soleil sont appelés "petits corps du Système Solaire".

resolution/5/preamble · preamble

fr · official · sha256:ceac3cc4865cbb4e92ac7fa8e3d69c89ae0ac37ac170fede3ea936b77044e16dFR

Les observations récentes ont changé notre vision des systèmes planétaires et il est important que la nomenclature des objets reflète notre compréhension actuelle. Ceci s’applique en particulier à la définition d’une "planète". Le mot "planète" désignait initialement les "vagabonds" du ciel, c'est-à-dire les points de lumière qui bougeaient par rapport aux étoiles. Les découvertes récentes nous conduisent à une nouvelle définition correspondant à l’état de nos connaissances.

resolution/5/resolves · provision

fr · official · sha256:f134b935228661c629430476ffaab2bfa570a6da556c72d8f2e15d12464188bdFR

En conséquence, l’Union Astronomique Internationale (U.A.I.) décide de répartir les planètes et autres corps du système solaire en trois catégories de la manière suivante:

resolution/6/heading · heading

fr · official · sha256:c81476589c31553c648b308784e682527974a895ad6f22e6b5239f53bba102fcFR

RESOLUTION 6: Pluton

resolution/6/text · provision

fr · official · sha256:414c25da3692f608de52fb71162f18a22b8dba57181fb07d98047e4b239f4e53FR

Conformément à la définition ci-dessus, Pluton est une planète naine. Il est identifié comme le prototype d’une nouvelle catégorie d’objets trans-neptuniens.

The hash beside the text is the sha256 of its exact bytes. It is the check that the text shown matches the one pinned in the package: a divergence fails the oracle’s static analysis.