Small_Solar_System_body

# Small Solar System body  **Microsim — three.js (Wikitube framework):** *What the Solar System holds (Solar System explorer)* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/solar/Solar_System.html?view=census&embed=1" data-title="What the Solar System holds (Solar System explorer)"></div> *The Solar System explorer locked on this article's state (`?view=census`); every object and population of the [[PORTAL_Solar_System|Solar System portal]] has its own state in the same scene.*  *Try: under show, choose small bodies to leave only the asteroids, trojans, centaurs, comets and trans-Neptunian points that make up this class; switch show to planets and moons to see everything the class leaves out; then choose everything, press l for labels, and scroll out from the asteroid belt to the Kuiper belt to compare the two main reservoirs.* A **small Solar System body** (SSSB) is any natural object orbiting the [[Sun]] that is not a planet, not a [[Dwarf_planet|dwarf planet]] and not a moon. The category was created by the International Astronomical Union in 2006, in the resolution that also set out the [[IAU_definition_of_planet|IAU definition of planet]], and it covers most [[Asteroid|asteroids]], every [[Comet|comet]], the [[Jupiter_trojan|trojans]], the [[Centaur_(small_Solar_System_body)|centaurs]] and all [[Trans-Neptunian_object|trans-Neptunian objects]] except those judged to be dwarf planets.[^iau-res] It is by far the most numerous class of body in the [[PORTAL_Solar_System|Solar System]]: the JPL Small-Body Database lists about 1.57 million asteroids and about 4,100 comets, and only a handful of these are dwarf planets.[^jpl-sbdb-q] The explorer at the top of this page opens on its census view, which colours bodies by class; the small bodies are the great majority of its points, far outnumbering the planets, dwarf planets and moons. ## Definition Resolution 5A of the IAU's 2006 General Assembly defines planets and dwarf planets and then states that all other objects orbiting the Sun, except satellites, are to be referred to collectively as small Solar System bodies.[^iau-res] The class is therefore defined by exclusion. A body qualifies if it orbits the Sun directly, is not in orbit around another body, and is neither a planet nor a dwarf planet, which in practice means it is too small to have been pulled round by its own gravity into [[Hydrostatics|hydrostatic equilibrium]]. The first condition rules out objects merely passing through: the interstellar visitors [[1I/ʻOumuamua|ʻOumuamua]] (2017), 2I/Borisov (2019) and 3I/ATLAS (2025) are on unbound, hyperbolic paths and are classed as [[Interstellar_object|interstellar objects]] instead.[^meech2017][^guzik2020][^seligman2025] The second condition separates small bodies from small moons by orbit, not size; a moon a few kilometres across and an asteroid of the same size differ only in what they circle. The boundary with the dwarf planets is left open, since several of the larger trans-Neptunian objects may prove to be round and move to that class.[^iau-res][^tancredi2008] No lower size limit is set. The IAU's meteor terminology calls natural solid objects from about 30 µm to 1 m across [[Meteoroid|meteoroids]], and smaller grains belong to the [[Interplanetary_dust_cloud|interplanetary dust cloud]]; whether the SSSB class reaches down that far is not specified.[^koschny2017] Most small bodies are concentrated in two reservoirs. The [[Asteroid_belt|asteroid belt]] between [[Mars]] and [[Jupiter]] holds about 1.47 million of the catalogued asteroids, and the [[Kuiper_belt|Kuiper belt]] and the region beyond hold about 7,300 known trans-Neptunian objects, a count limited by how faint they are rather than by how many exist (derived).[^jpl-sbdb-q][^jewitt1993] Both have internal structure set by the giant planets: Jupiter's resonances open the [[Kirkwood_gap|Kirkwood gaps]] in the inner reservoir, and Neptune's resonances shape the outer one. Smaller populations fill the space between: about 42,000 [[Near-Earth_object|near-Earth objects]], about 16,000 Jupiter trojans and about 1,000 centaurs (derived).[^jpl-sbdb-q] In the explorer these populations appear as sampled points; the points are ILLUSTRATIVE of each population's extent, while the orbits of named individual bodies come from the JPL Small-Body Database.[^jpl-sbdb] ## See also - [[Asteroid]] · [[Comet]] · [[Meteoroid]] - [[Centaur_(small_Solar_System_body)]] - [[Near-Earth_object]] · [[Jupiter_trojan]] · [[Hilda_asteroid]] - [[Dwarf_planet]] · [[IAU_definition_of_planet]] - Lists of small Solar System bodies (plain text: not yet on Wikitube) ## References [^iau-res]: International Astronomical Union (24 August 2006). "IAU 2006 General Assembly: Resolutions 5 and 6" (Resolution B5, Definition of a Planet in the Solar System). https://iauarchive.eso.org/static/resolutions/Resolution_GA26-5-6.pdf [^jpl-sbdb-q]: JPL Solar System Dynamics. Small-Body Database Query API, counts by kind and orbit class (asteroids, comets; classes IMB, MBA, OMB, TNO, CEN, TJN, IEO, ATE, APO, AMO). https://ssd-api.jpl.nasa.gov/doc/sbdb_query.html (queried 2026-09-18). [^jpl-sbdb]: JPL Solar System Dynamics. Small-Body Database Lookup. https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html (elements fetched 2026-09-18). [^meech2017]: Meech, K. J.; Weryk, R.; Micheli, M.; et al. (2017). "A brief visit from a red and extremely elongated interstellar asteroid". *Nature* 552: 378–381. https://doi.org/10.1038/nature25020 [^guzik2020]: Guzik, P.; Drahus, M.; Rusek, K.; Waniak, W.; et al. (2020). "Initial characterization of interstellar comet 2I/Borisov". *Nature Astronomy* 4: 53–57. https://doi.org/10.1038/s41550-019-0931-8 [^seligman2025]: Seligman, D. Z.; Micheli, M.; Farnocchia, D.; Denneau, L.; et al. (2025). "Discovery and preliminary characterization of a third interstellar object: 3I/ATLAS". *The Astrophysical Journal Letters* 989: L36. https://doi.org/10.3847/2041-8213/adf49a [^tancredi2008]: Tancredi, G.; Favre, S. (2008). "Which are the dwarfs in the Solar System?". *Icarus* 195: 851–862. https://doi.org/10.1016/j.icarus.2007.12.020 [^koschny2017]: Koschny, D.; Borovička, J. (2017). "Definitions of terms in meteor astronomy". *WGN, Journal of the International Meteor Organization* 45: 91–92. [^jewitt1993]: Jewitt, D.; Luu, J. (1993). "Discovery of the candidate Kuiper belt object 1992 QB1". *Nature* 362: 730–732. https://doi.org/10.1038/362730a0 ## External links - International Astronomical Union: Resolutions B5 and B6 (2006). https://iauarchive.eso.org/static/resolutions/Resolution_GA26-5-6.pdf - JPL Small-Body Database Lookup. https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html - IAU Minor Planet Center. https://minorplanetcenter.net/ - NASA Science: Asteroids, comets and meteors. https://science.nasa.gov/solar-system/asteroids/ ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Small_Solar_System_body) : [Wikitube](https://en.wikitube.io/wiki/Small_Solar_System_body) · pinned revision [1350157988](https://en.wikipedia.org/w/index.php?oldid=1350157988) · 2026-09-18 ## Previous hub tags Hubs: `Life_Physics`. Portals: [[PORTAL_Solar_System]]. --- *Solar System portal child articles, wave 1 · 2026-09-18 · drafted · row SOL-032 · explorer state `?view=census`.*