Editing Trans-Neptunian object (section)

=== Color indices {{anchor|Colors|Colours}} ===
{{See also|Asteroid color indices}}
[[File:Trans-Neptunians_Size_Albedo_Color.svg|thumb|upright=1.5|Comparison of sizes, albedo, and colors of various large trans-Neptunian objects with sizes of >700 km. The dark colored arcs represent uncertainties of the object's size.]]

[[Colour indices]] are simple measures of the differences in the [[apparent magnitude]] of an object seen through blue (B), visible (V), i.e. green-yellow, and red (R) filters. The diagram illustrates known colour indices for all but the biggest objects (in slightly enhanced colour).<ref name="Hainaut, Delsanti 2002">{{cite journal |author-link=Olivier R. Hainaut |first1=O. R. |last1=Hainaut |first2=A. C. |last2=Delsanti |date=2002 |title=Color of Minor Bodies in the Outer Solar System |journal=Astronomy & Astrophysics |volume=389 |issue=2 |pages=641–664 |doi=10.1051/0004-6361:20020431 |bibcode = 2002A&A...389..641H |doi-access=free }} [http://www.sc.eso.org/~ohainaut/MBOSS datasource]</ref>
For reference, two moons, [[Triton (moon)|Triton]] and [[Phoebe (moon)|Phoebe]], the centaur [[5145 Pholus|Pholus]] and the planet [[Mars]] are plotted ''(yellow labels, size not to scale)''. Correlations between the colours and the orbital characteristics have been studied, to confirm theories of different origin of the different dynamic classes:
* [[Classical Kuiper belt object]] (cubewano) seem to be composed of two different colour populations: the so-called cold (inclination <5°) population, displaying only red colours, and the so-called hot (higher inclination) population displaying the whole range of colours from blue to very red.<ref name="Doressoundiram 2005">{{cite journal |author-link1=Alain Doressoundiram |first1=A. |last1=Doressoundiram |first2=N. |last2=Peixinho |author-link3=Catherine de Bergh |first3=C. |last3=de Bergh |author-link4=Sonia Fornasier |first4=S. |last4=Fornasier |author-link5=Philippe Thébault |first5=Ph. |last5=Thébault |author-link6=Maria A. Barucci |first6=M. A. |last6=Barucci |author-link7=Christian Veillet |first7=C. |last7=Veillet |title=The color distribution in the Edgeworth-Kuiper Belt |journal=The Astronomical Journal |volume=124 |issue=4 |pages=2279–2296 |doi=10.1086/342447 |arxiv = astro-ph/0206468 |bibcode = 2002AJ....124.2279D |year=2002 |s2cid=30565926 }}</ref> A recent analysis based on the data from [[Deep Ecliptic Survey]] confirms this difference in colour between low-inclination (named ''Core'') and high-inclination (named ''Halo'') objects. Red colours of the Core objects together with their unperturbed orbits suggest that these objects could be a relic of the original population of the belt.<ref name="Elliot2006">{{cite journal |last1=Gulbis |first1=Amanda A. S. |last2=Elliot |first2=J. L. |last3=Kane |first3=Julia F. |title=The color of the Kuiper belt Core |journal=[[Icarus (journal)|Icarus]] |volume=183 |date=2006 |issue=1 |pages=168–178 |doi=10.1016/j.icarus.2006.01.021 |bibcode = 2006Icar..183..168G }}</ref>
*[[Scattered disc]] objects show colour resemblances with hot classical objects pointing to a common origin.

While the relatively dimmer bodies, as well as the population as the whole, are reddish (V−I = 0.3–0.6), the bigger objects are often more neutral in colour (infrared index V−I < 0.2). This distinction leads to suggestion that the surface of the largest bodies is covered with ices, hiding the redder, darker areas underneath.<ref name="Rabinowitz 2005">{{cite journal |author-link=David L. Rabinowitz |first1=David L. |last1=Rabinowitz |first2=K. M. |last2=Barkume |author-link3=Michael E. Brown |first3=Michael E. |last3=Brown |first4=H. G. |last4=Roe |first5=M. |last5=Schwartz |first6=S. W. |last6=Tourtellotte |author-link7=C. A. Trujillo |first7=C. A. |last7=Trujillo |date=2006 |title=Photometric Observations Constraining the Size, Shape, and Albedo of 2003 El<sub>61</sub>, a Rapidly Rotating, Pluto-Sized Object in the Kuiper Belt |journal=Astrophysical Journal |volume=639 |issue=2 |pages=1238–1251 |doi=10.1086/499575 |arxiv = astro-ph/0509401 |bibcode = 2006ApJ...639.1238R |s2cid=11484750 }}</ref>

{| class="wikitable" style="text-align: center;"
|+ Mean-color indices of [[List of minor-planet groups|dynamical groups]] in the [[outer Solar System]]&thinsp;<ref name="Fornasier-2007"/>{{rp|35}}
! Color
! width= 120 | [[Plutino]]s
! width= 120 | [[Cubewano]]s
! width= 120 | [[Centaur (minor planet)|Centaurs]]
! width= 120 | [[Scattered disc object|SDOs]]
! width= 120 | [[Comet]]s
! width= 120 | [[Jupiter trojan]]s
|-
! B–V
| {{val|0.895|0.190}}
| {{val|0.973|0.174}}
| {{val|0.886|0.213}}
| {{val|0.875|0.159}}
| {{val|0.795|0.035}}
| {{val|0.777|0.091}}
|-
! V–R
| {{val|0.568|0.106}}
| {{val|0.622|0.126}}
| {{val|0.573|0.127}}
| {{val|0.553|0.132}}
| {{val|0.441|0.122}}
| {{val|0.445|0.048}}
|-
! V–I
| {{val|1.095|0.201}}
| {{val|1.181|0.237}}
| {{val|1.104|0.245}}
| {{val|1.070|0.220}}
| {{val|0.935|0.141}}
| {{val|0.861|0.090}}
|-
! R–I
| {{val|0.536|0.135}}
| {{val|0.586|0.148}}
| {{val|0.548|0.150}}
| {{val|0.517|0.102}}
| {{val|0.451|0.059}}
| {{val|0.416|0.057}}
|}