Template:Minor planet color code legend/doc

Color code for orbital classification of numbered minor planets

The colorization is based on the following defining criteria of a minor planet's (MPs) orbital elements such as semimajor axis a, perihelion distance q, aphelion distance Q, and orbital eccentricity e. Figures below give the actual number distribution of MPs by color-coded orbital class. They are used in the color-coded partial lists of minor planets.

Principal orbital groups	MPs (#)	MPs (%)	Distribution	Orbital criteria
Near-Earth object(a)	3,104	0.50%		q < 1.3 AU
Mars-crosser	6,180	1.00%		1.3 AU < q < 1.666 AU; a < 3.2 AU
MBA (inner)	195,710	31.74%		a < 2.5 AU; q > 1.666 AU
MBA (middle)	216,729	35.14%		2.5 AU < a < 2.82 AU; q > 1.666 AU
MBA (outer)	187,562	30.41%		2.82 AU < a < 4.6 AU; q > 1.666 AU
Jupiter trojan	6,300	1.02%		4.6 AU < a < 5.5 AU; e < 0.3
Centaur	158	0.03%		5.5 AU < a < 30.1 AU
Trans-Neptunian object	912	0.15%		a > 30.1 AU
Total (numbered)	616,690(b)	100%		Source: JPL's SBDB

^(a) NEO-subgroups with number of members: Aten (255), Amor (1,275), Apollo (1,566) and Atira (8) asteroids.

^(b) Including 35 unclassified bodies: 6144 Kondojiro, 8373 Stephengould, 9767 Midsomer Norton, (18916) 2000 OG₄₄, (32511) 2001 NX₁₇, (96177) 1984 BC, (115916) 2003 WB₈, (136620) 1994 JC, (144870) 2004 MA₈, (241944) 2002 CU₁₄₇, (275618) 2000 AU₂₄₂, (301964) 2000 EJ₃₇, (306418) 1998 KK₅₆, (322713) 2000 KD₄₁, (363135) 2001 QQ₁₉₉, (393350) 1992 RN₁, (405058) 2001 TX₁₆, (406803) 2008 UX₆₄, (477587) 2010 JT₈₆, (487496) 2014 SE₂₈₈, (490171) 2008 UD₂₅₃, (494667) 2001 WX₁, (497009) 2003 BU₃₅, (497619) 2006 QL₃₉, (504160) 2006 SV₃₀₁, 514107 Ka`epaoka`awela, (518509) 2006 FZ₅₁, (524114) 2000 SB₁, (526889) 2007 GH₆, (584530) 2017 GY₁₀, (612078) 1998 UQ₁, (612320) 2001 XE₁₀₄, (613709) 2007 CM₅₇, (613987) 2008 JO₂₀, (614590) 2009 XY₂₁ (colored as    for being unclassified).

Hexadecimal map

Code	Group	Code	Group
#FFC2E0	NEOs	#FA8072	MCs
#FEFEFE	MBA (inner)	#E9E9E9	MBA (middle)
#D6D6D6	MBA (outer)	#C2FFFF	JTs
#C7FF8F	Centaurs	#C2E0FF	TNOs
#B88A00	unclassified

Sources for classification

The orbital classification largely follows JPL's conventions (see definitions below), except for the boundary of inner/outer main-belt asteroids which are grouped by the two major Kirkwood gaps (a at 2.5 and 2.82 AU, instead of JPL's 2.0 and 3.2 AU). Also the Apollo, Amor, Aten, and Atira groups have no distinct color and are displayed with one color as NEOs. For outer main-belt asteroids, the criteria "q > 1.666 AU" has also been added.

• MCAs Asteroids that cross the orbit of Mars constrained by (1.3 AU < q < 1.666 AU; a < 3.2 AU).
• JTs Asteroids trapped in Jupiter's L4/L5 Lagrangian points (4.6 AU < a < 5.5 AU; e < 0.3).
• CEN Objects with orbits between Jupiter and Neptune (5.5 AU < a < 30.1 AU).
• TNO Objects with orbits outside Neptune (a > 30.1 AU).
• MBA (middle) Asteroids with orbital elements constrained by (2.0 AU < a < 3.2 AU; q > 1.666 AU).
• MBA (inner) Asteroids with orbital elements constrained by (a < 2.0 AU; q > 1.666 AU).
• MBA (outer) Asteroids with orbital elements constrained by (3.2 AU < a < 4.6 AU).
• APO Near-Earth asteroid orbits which cross the Earth's orbit similar to that of 1862 Apollo (a > 1.0 AU; q < 1.017 AU).
• ATE Near-Earth asteroid orbits similar to that of 2062 Aten (a < 1.0 AU; Q > 0.983 AU).
• AMO Near-Earth asteroid orbits similar to that of 1221 Amor (1.017 AU < q < 1.3 AU).
• ATI Asteroid orbits contained entirely within the orbit of the Earth (Q < 0.983 AU). Also known as Interior Earth Objects.

Remarks

• Unclassified: A handful of minor planets can not be classified with the above given criteria. These are objects with a semi-major axis corresponding to those of Jupiter trojans, but with an eccentricity larger than 0.3. Others are Mars-crossing (MPC) outer main-belt asteroids (JPL).
• Divergent classification: A relatively larger number of objects may be differently classified . In particular, JPL's Small-Body Database and the Minor Planet Center's website often do not agree on the distinction of main-belt Hungaria and Mars-crosser asteroids.
• {{Infobox planet}}: adjust the background color of the heading sections in {{Infobox planet}} to the above color scheme with |background=. This allows for a basic distinction of NEOs, MBAs, Jupiter trojans, centaurs and TNOs at first glance. Since the background of the infobox itself already uses a light-grey background color, the heading sections should use #D6D6D6 for all main-belt object articles, irrespective whether they are inner, middle or outer belt asteroids.