List of Solar System objects by size


This is a partial list of Solar System objects by size, arranged in descending order of mean volumetric radius, and divided into several size classes. These lists can also be sorted according to an object's mass and, for the largest objects, volume, density and surface gravity, insofar as these values are available. This list contains the Sun, the planets, dwarf planets, many of the larger small Solar System bodies, all named natural satellites, and a number of smaller objects of historical or scientific interest, such as comets and near-Earth objects.
Objects on this list are ordered by mean radius rather than mass; thus, objects on the lower portions of the table can be more massive than objects higher on the list if they have a higher density.
Many trans-Neptunian objects have been discovered; in many cases their positions in this list are approximate, as there is frequently a large uncertainty in their estimated diameters.
Solar System objects more massive than 1021 kilograms are known or expected to be approximately spherical. Astronomical bodies relax into rounded shapes, achieving hydrostatic equilibrium, when their own gravity is sufficient to overcome the structural strength of their material. It was believed that the cutoff for round objects is somewhere between 100 km and 200 km in radius if they have a large amount of ice in their makeup; however, later studies revealed that icy satellites as large as Iapetus are not in hydrostatic equilibrium at this time, and a 2019 assessment suggests that many TNOs in the size range of 400-1000 kilometers may not even be fully solid bodies, much less gravitationally rounded. Objects that are ellipsoids due to their own gravity are here generally referred to as being "round", whether or not they are actually in equilibrium today, while objects that are clearly not ellipsoidal are referred to as being "irregular".
Spheroidal bodies typically have some polar flattening due to the centrifugal force from their rotation, and can sometimes even have quite different equatorial diameters. Unlike bodies such as Haumea, the irregular bodies have a significantly non-ellipsoidal profile, often with sharp edges.
There can be difficulty in determining the diameter for typical objects beyond Saturn. For TNOs there is some confidence in the diameters, but for non-binary TNOs there is no real confidence in the masses/densities. Many TNOs are often just assumed to have Pluto's density of 2.0 g/cm3, but it is just as likely that they have a comet-like density of only 0.5 g/cm3. For example, if a TNO is incorrectly assumed to have a mass of 3.59 kg based on a radius of 350 km with a density of 2 g/cm3 but is later discovered to have a radius of only 175 km with a density of 0.5 g/cm3, its true mass would be only 1.12 kg.
The sizes and masses of many of the moons of Jupiter and Saturn are fairly well known due to numerous observations and interactions of the Galileo and Cassini orbiters; however, many of the moons with a radius less than ~100 km, such as Jupiter's Himalia, have far less certain masses. Further out from Saturn, the sizes and masses of objects are less clear. There has not yet been an orbiter around Uranus or Neptune for long-term study of their moons. For the small outer irregular moons of Uranus, such as Sycorax, which were not discovered by the Voyager 2 flyby, even different NASA web pages, such as the National Space Science Data Center and JPL Solar System Dynamics, give somewhat contradictory size and albedo estimates depending on which research paper is being cited.
There are uncertainties in the figures for mass and radius, and irregularities in the shape and density, with accuracy often depending on how close the object is to Earth or whether it has been visited by a probe.

Graphical overview

List of objects by mean radius

Larger than 400 km

It was once expected that any icy body larger than approximately 200 km in radius was likely to be in hydrostatic equilibrium. However, is the smallest body for which detailed measurements are consistent with hydrostatic equilibrium, whereas Iapetus is the largest icy body that has been found to not be in hydrostatic equilibrium.
For simplicity and comparative purposes, the values are manually calculated assuming a sphericity of 1. The size of solid bodies does not include an object's atmosphere. For example, Titan looks bigger than Ganymede, but its solid body is smaller. For the giant planets, the "radius" is defined as the distance from the center at which the atmosphere reaches 1 bar of atmospheric pressure. The radius of Saturn's main rings is 136,775 km.

From 200 to 399 km

All imaged icy moons with radii greater than 200 km except Proteus are clearly round, although those under 400 km that have had their shapes carefully measured are not in hydrostatic equilibrium. The known densities of TNOs in this size range are remarkably low, implying that the objects retain significant internal porosity from their formation and were never gravitationally compressed into fully solid bodies.

From 100 to 199 km

This list contains a selection of objects estimated to be between 100 and 199 km in radius. The largest of these may lie above the boundary for hydrostatic equilibrium, but most are irregular. Most of the trans-Neptunian objects listed with a radius smaller than 200 km have "assumed sizes based on a generic albedo of 0.09" since they are too far away to directly measure their sizes with existing instruments. Mass switches from 1021 kg to 1018 kg. Main-belt asteroids have orbital elements constrained by according to JPL Solar System Dynamics. Many TNOs are omitted from this list as their sizes are poorly known.

From 50 to 99 km

This list contains a selection of objects 50 and 99 km in radius. The listed objects currently include most objects in the asteroid belt and moons of the giant planets in this size range, but many newly discovered objects in the outer Solar System are missing, such as those included in the following reference. Asteroid spectral types are mostly Tholen, but some might be SMASS.
BodyImageRadius
'
Mass
TypeRefs
'
Bienor
54598
centaurM
Themis
24
belt asteroid type C
Larissa
Neptune VII
moon of Neptune
Ursula
375
belt asteroid type C
Amphitrite
29
belt asteroid type S
Daphne
41
belt asteroid type C; binary
Aurora
94
belt asteroid type C
Hermione
121
outer belt asteroid type C; binary
Bertha
154
belt asteroid type C
Hebe
6
belt asteroid type S
Metis
9
belt asteroid type S
Elektra
130
belt asteroid type G; trinary
Janus
Saturn X
moon of Saturn
Teharonhiawako
88611
cubewano; binary
Aegle
96
belt asteroid type T
S/2015 1
Makemake I
moon of MakemakeM
Galatea
Neptune VI
moon of Neptune
Phorcys
Ceto I
secondary of 65489 Ceto
Palma
372
belt asteroid type B
Alauda
702
belt asteroid type C; binary
Hilda
153
outer belt asteroid; HildasM
Himalia
Jupiter VI
moon of Jupiter
Namaka
Haumea II
moon of Haumea
Weywot
Quaoar I
moon of 50000 Quaoar
Freia
76
outer belt asteroid type P/type X
Kalliope
22
belt asteroid type M; binary
Amalthea
Jupiter V
moon of Jupiter
Agamemnon
911
Jupiter trojan type DM
Elpis
59
belt asteroid type CP/type B
Puck
Uranus XV
moon of UranusM
Sycorax
Uranus XVII
moon of UranusM
Despina
Neptune V
moon of NeptuneM
Io
85
belt asteroid type FC/type B
Minerva
93
belt asteroid type C; trinary
Alexandra
54
belt asteroid type C
Laetitia
39
belt asteroid type S
Parthenope
11
belt asteroid type S
Manwë
385446
resonant KBO ; binary
Pales
49
belt asteroid type C
Arethusa
95
belt asteroid type CM
Flora
8
belt asteroid type S
Pulcova
762
belt asteroid type F; binary
Julia
89
belt asteroid type S
Irene
14
belt asteroid type S
Aglaja
47
belt asteroid type C
Patroclus
617
Jupiter trojan type P; binary
Melpomene
18
belt asteroid type S
Nemausa
51
belt asteroid type G
Hesperia
69
belt asteroid type M
Typhon
42355
resonant SDO ; binary
Massalia
20
belt asteroid type S
Portia
Uranus XII
moon of UranusM
Emma
283
belt asteroid type X; binary
Paha
Lempo I
moon of 47171 Lempo
Lucina
146
belt asteroid type CM
Sawiskera
Teharonhiawako I
secondary of 88611 TeharonhiawakoM
Kleopatra
216
belt asteroid type M; trinary
Achilles
588
Jupiter trojan type DUM
Panopaea
70
belt asteroid type C
Thule
279
belt asteroid type DM
Borasisi
66652
cubewano; binary
Hestia
46
belt asteroid type P/type Xc
Leto
68
belt asteroid type S
Undina
92
belt asteroid type X
Bellona
28
belt asteroid type S
Diana
78
belt asteroid type C
Anchises
1173
Jupiter trojan type PM
Galatea
74
belt asteroid type C
Deiphobus
1867
Jupiter trojan type DM
Äneas
1172
Jupiter trojan type DM
Diomedes
1437
Jupiter trojan type DM
Terpsichore
81
belt asteroid type C
Epimetheus
Saturn XI
moon of Saturn
Circe
34
belt asteroid type C
Leda
38
belt asteroid type C
Victoria
12
belt asteroid type S
Odysseus
1143
Jupiter trojan type DM
Alcathous
2241
Jupiter trojan type DM
Melete
56
belt asteroid type P
Mnemosyne
57
belt asteroid type S
Nestor
659
Jupiter trojan type XCM
Harmonia
40
belt asteroid type SM
Leleākūhonua
541132
sednoidM
Euterpe
27
belt asteroid type S
Antilochus
1583
Jupiter trojan type DM
Thorondor
Manwë I
secondary of 385446 Manwë
Thalia
23
belt asteroid type S
Erato
62
belt asteroid type BU/type ChM
Astraea
5
belt asteroid type S
Pabu
Borasisi I
secondary of 66652 BorasisiM
Eos
221
belt asteroid type S/type K
Aegina
91
belt asteroid type CM
Leukothea
35
belt asteroid type CM
Menoetius
Patroclus I
secondary of 617 PatroclusM
Isis
42
belt asteroid type S
Klotho
97
belt asteroid type M
Troilus
1208
Jupiter trojan type FCUM

From 20 to 49 km

This list includes few examples since there are about 589 asteroids in the asteroid belt with a measured radius between 20 and 49 km. Many thousands of objects of this size range have yet to be discovered in the trans-Neptunian region. The number of digits is not an endorsement of significant figures. The table switches from kg to kg. Most mass values of asteroids are assumed.
BodyImageRadius
'
Mass
Type – notesRefs
'
Asterope
233
belt asteroid type T/type KM
Pholus
5145
centaurM
Thebe
Jupiter XIV
moon of JupiterM
Lutetia
21
belt asteroid type M
Kalypso
53
belt asteroid type XC
Proserpina
26
belt asteroid type S
Juliet
Uranus XI
moon of UranusM
Urania
30
belt asteroid type S
Ausonia
63
belt asteroid type S
Beatrix
83
belt asteroid type XM
Concordia
58
belt asteroid type CM
Echidna
Typhon I
moon of 42355 TyphonM
Automedon
2920
Jupiter trojan type DM
90 Antiopebelt asteroid type C; binary
Prometheus
Saturn XVI
moon of Saturn
Danaë
61
belt asteroid type S
Thetis
17
belt asteroid type S
Pandora
55
belt asteroid type MM
Huenna
379
belt asteroid type B/type C; binary
Virginia
50
belt asteroid type X/type Ch
Feronia
72
belt asteroid type TDG
S/2000 1
Antiope I
secondary of 90 AntiopeM
Poulydamas
4348
Jupiter trojan type CM
Logos
58534
cubewano; binary
Pandora
Saturn XVII
moon of Saturn
Thalassa
Neptune IV
moon of NeptuneM
Niobe
71
belt asteroid type SM
Pomona
32
belt asteroid type SM
Belinda
Uranus XIV
moon of UranusM
Elara
Jupiter VII
moon of JupiterM
Cressida
Uranus IX
moon of UranusM
Amycus
55576
centaurM
Hylonome
10370
centaurM

3708
Jupiter trojan type CM
Nysa
44
belt asteroid type EM
Rosalind
Uranus XIII
moon of UranusM
Maja
66
belt asteroid type CM
Ariadne
43
belt asteroid type S
Iphigenia
112
belt asteroid type C
Dike
99
belt asteroid type CM
Echeclus
60558 or 174P
centaurM
Desdemona
Uranus X
moon of UranusM
Eurybates
3548
Jupiter trojan type CPM
Eurynome
79
belt asteroid type SM
Eurydike
75
belt asteroid type MM
Halimede
Neptune IX
moon of NeptuneM
Phocaea
25
belt asteroid type S
Naiad
Neptune III
moon of NeptuneM
Schwassmann–
Wachmann 1
29P
cometM
Neso
Neptune XIII
moon of NeptuneM
Angelina
64
belt asteroid type EM
Pasiphae
Jupiter VIII
moon of JupiterM
Alkmene
82
belt asteroid type SM
Nessus
7066
centaurM
Polana
142
belt asteroid type FM
Bianca
Uranus VIII
moon of UranusM
Mathilde
253
belt asteroid type C
Hidalgo
944
centaurM
Orus
21900
Jupiter trojan type C/type DM
Amalthea
113
belt asteroid type S; binaryM
Prospero
Uranus XVIII
moon of UranusM
Setebos
Uranus XIX
moon of UranusM
Carme
Jupiter XI
moon of JupiterM
Klytia
73
belt asteroid type SM
Sao
Neptune XI
moon of NeptuneM
Echo
60
belt asteroid type S
Metis
Jupiter XVI
moon of Jupiter
Ophelia
Uranus VII
moon of UranusM
Lysithea
Jupiter X
moon of JupiterM
Caliban
Uranus XVI
moon of UranusM
Laomedeia
Neptune XII
moon of NeptuneM
Cordelia
Uranus VI
moon of UranusM
Psamathe
Neptune X
moon of NeptuneM

From 1 to 19 km

This list contains some examples of Solar System objects between 1 and 19 km in radius. This is a common size for asteroids, comets, and moons.
BodyImageRadius
'
Mass
Type – notesRefs
'
Urda
167
belt asteroid type SM
Hydra
Pluto III
moon of Pluto
Siarnaq
Saturn XXIX
moon of SaturnM
Koronis
158
belt asteroid type SM
Nix
Pluto II
moon of Pluto
Ganymed
1036
Amor asteroid type S
Okyrhoe
52872
centaurM
Helene
Saturn XII
moon of Saturn; Dione trojan M
Sinope
Jupiter IX
moon of JupiterM
Hippocamp
Neptune XIV
moon of Neptune
Leucus
11351
Jupiter trojan type DM
Stephano
Uranus XX
moon of UranusM
Arrokoth
486958
cubewano; contact binaryM
Ida
243
belt asteroid type S; binary
Atlas
Saturn XV
moon of Saturn
Ananke
Jupiter XII
moon of JupiterM
Albiorix
Saturn XXVI
moon of SaturnM
Pan
Saturn XVIII
moon of Saturn
Linus
Kalliope I
asteroid moon of 22 Kalliope
Dioretsa
20461
centaur; damocloidM
Perdita
Uranus XXV
moon of UranusM
Telesto
Saturn XIII
moon of Saturn; Tethys trojan M
Mab
Uranus XXVI
moon of UranusM
Phobos
Mars I
moon of Mars
Paaliaq
Saturn XX
moon of SaturnM
Francisco
Uranus XXII
moon of UranusM
Leda
Jupiter XIII
moon of JupiterM
Calypso
Saturn XIV
moons of Saturn; Tethys trojan M
Polymele
15094
Jupiter trojan type PM
Margaret
Uranus XXIII
moon of UranusM
Ferdinand
Uranus XXIV
moon of UranusM
Cupid
Uranus XXVII
moon of UranusM
Ymir
Saturn XIX
moon of SaturnM
Trinculo
Uranus XXI
moon of UranusM
Eros
433
Amor asteroid type S
Adrastea
Jupiter XV
moon of JupiterM
Kiviuq
Saturn XXIV
moon of SaturnM
Tarvos
Saturn XXI
moon of SaturnM
Kerberos
Pluto IV
moon of Pluto
Gaspra
951
belt asteroid type S
Deimos
Mars II
moon of Mars
Skamandrios
Hektor I
asteroid moon of 624 HektorM
Ijiraq
Saturn XXII
moon of SaturnM
Halley's Comet
1P
comet
Styx
Pluto V
moon of Pluto
Romulus
Sylvia I
asteroid moon of 87 SylviaM
Masursky
2685
belt asteroid type SM
Erriapus
Saturn XXVIII
moon of SaturnM
Callirrhoe
Jupiter XVII
moon of JupiterM
Alexhelios
Kleopatra I
asteroid moon of 216 KleopatraM
Esclangona
1509
inner belt asteroid type S; binaryM
Themisto
Jupiter XVIII
moon of JupiterM
Daphnis
Saturn XXXV
moon of Saturn
Petit-Prince
Eugenia I
asteroid moon of 45 EugeniaM
Praxidike
Jupiter XXVII
moon of JupiterM
Bestla
Saturn XXXIX
moon of SaturnM
Remus
Sylvia II
asteroid moon of 87 SylviaM
Kalyke
Jupiter XXIII
moon of JupiterM
Cleoselene
Kleopatra II
asteroid moon of 216 KleopatraM
S/2019 1
Euphrosyne I
asteroid moon of 31 EuphrosyneM
Tempel 1
9P
Jupiter-family comet; Deep Impact flyby and impactedM
Phaethon
3200
Apollo asteroid type FM

53319
Apollo asteroid type XM
Borrelly
19P
Jupiter-family cometM
Šteins
2867
belt asteroid type EM
Atira
163693
Atira asteroid type S; binaryM
Annefrank
5535
belt asteroid type SM
Balam
3749
belt asteroid type S; trinary
Pallene
Saturn XXXIII
moon of SaturnM
Florence
3122
Amor asteroid type S; trinary
Wild 2
81P
Jupiter family cometM
Litva
2577
Mars-crosser type EU; trinaryM
Churyumov–Gerasimenko
67P
Jupiter-family comet
Donaldjohanson
52246
belt asteroid type CM
Cuno
4183
Apollo asteroid type S/type QM

6178
Amor asteroid type MM
Pichi üñëm
Alauda I
asteroid moon of 702 AlaudaM
Toutatis
4179
Apollo asteroid type S
Methone
Saturn XXXII
moon of SaturnM

285263
Amor asteroid type S; binaryM
Polydeuces
Saturn XXXIV
moon of Saturn; Dione trojan M

153591
Amor asteroid type C; trinary
S/2003 1
Esclangona I
asteroid moon of 1509 EsclangonaM
APL
132524
belt asteroid type SM
Camillo
3752
Apollo asteroid type SM
Cruithne
3753
Aten asteroid type Q; quasi-satellite of EarthM

Below 1 km

This list contains examples of objects below 1 km in radius. That means that irregular bodies can have a longer chord in some directions, hence the mean radius averages out.
In the asteroid belt alone there are estimated to be between 1.1 and 1.9 million objects with a radius above 0.5 km, many of which are in the range 0.5–1.0 km. Countless more have a radius below 0.5 km.
Very few objects in this size range have been explored or even imaged. The exceptions are objects that have been visited by a probe, or have passed close enough to Earth to be imaged. Radius is by mean geometric radius. Number of digits not an endorsement of significant figures. Mass scale shifts from × 1015 to 109 kg, which is equivalent to one billion kg or 1012 grams.
Currently most of the objects of mass between 109 kg to 1012 kg listed here are near-Earth asteroids. The Aten asteroid has less mass than the Great Pyramid of Giza, 5.9 × 109 kg.
For more about very small objects in the Solar System, see meteoroid, micrometeoroid, and interplanetary dust cloud. '
BodyImageRadius
'
Mass
Type – notesRefs
Ra-Shalom
2100
Aten asteroid type CM
Geographos
1620
Apollo asteroid type SM
Midas
1981
Apollo asteroid type SM
Mithra
4486
Apollo asteroid type SM

12538
Apollo asteroid type SM
Tantalus
2102
Apollo asteroid type QM
Braille
9969
Mars-crosser type QM

308242
Aten asteroid type SM
Apollo
1862
Apollo asteroid type QM

85989
Aten asteroid type K; contact binaryM
Icarus
1566
Apollo asteroid type SM
Dactyl
Ida I
asteroid moon of 243 IdaM
Castalia
4769
Apollo asteroid type S; contact binaryM

214869
Apollo asteroid type QM
Moshup
66391
Aten asteroid type S; binary

29075
Apollo asteroid type S

394130
Apollo asteroidM
Hartley 2
103P
Jupiter-family comet

163899
Aten asteroid type SM
Nyx
3908
Amor asteroid type VM

153814
Apollo asteroidM
Apollo asteroid type S; binaryM
Ryugu
162173
Apollo asteroid type Cg

162058
Amor asteroid type SM
Apollo asteroid type S; contact binaryM
Hermes
69230
Apollo asteroid type SqM
Didymos
65803
Apollo asteroid type Xk; binary
Aten
2062
Aten asteroid type SM
Aegaeon
Saturn LIII
moon of SaturnM
Apollo asteroid type SM

136617
Apollo asteroid type Sq; trinary

172034
Amor asteroid type SM
Golevka
6489
Apollo asteroid type QM
Bennu
101955
Apollo asteroid type B

153201
Aten asteroid type XM

163132
Apollo asteroidM
Squannit
asteroid moon of 66391 MoshupM
Aten asteroid type SM
Apollo asteroidM

341843
Aten asteroid type X/type CM

388188
Apollo asteroid type S; contact binaryM

6037
Apollo asteroid type SM
Aten asteroid; Earth trojan M

292220
Apollo asteroid

308635
Apollo asteroid type CM
Apollo asteroid; co-orbital with EarthM
Itokawa
25143
Apollo asteroid type S
Apophis
99942
Aten asteroid type Sq
S/2009 S 1moon of SaturnM
Apollo asteroid type SM

357439
Apollo asteroid type V; binaryM
Apollo asteroid type SM
Aten asteroid type X; co-orbital with VenusM

436724
Apollo asteroid type SM
Dimorphos
Didymos I
asteroid moon of 65803 DidymosM
Apollo asteroid type SM
YORP
54509
Apollo asteroid type SM
Kamoʻoalewa
469219
Apollo asteroid type S; quasi-satellite of EarthM
Duende
367943
Aten asteroid type LM
Apollo asteroid type XM
Apollo asteroid type E/type XeM
2014 RCApollo asteroid type SqM
Apollo asteroid
2011 MDApollo asteroid/Amor asteroid type SM
Apollo asteroid type F/type M
Apollo asteroidM

Surface gravity

The surface gravity at the equator of a body can in most cases be accurately calculated using Newton's law of universal gravitation and centrifugal force.
The gravitational acceleration at the equator is given by Newton's law of universal gravitation. The formula that follows from this law is:
where
The magnitude of the outward acceleration due to centrifugal force is given by
where
The surface gravity at the equator is then given by: