List of gravitationally rounded objects of the Solar System

Summary

This is a list of possibly gravitationally rounded objects of the Solar System, which are objects that have a rounded, ellipsoidal shape due to their own gravity (hydrostatic equilibrium). Their sizes range from planetary-mass objects like dwarf planets and some moons to the planets and the Sun. This list does not include small Solar System bodies, but it does include a sample of possible planetary-mass objects whose shapes have yet to be determined. The Sun's orbital characteristics are listed in relation to the Galactic Center, while all other objects are listed in order of their distance from the Sun.

Star

The Sun is a G-type main-sequence star. It contains almost 99.9% of all the mass in the Solar System.[1]

Sun[2][3]
Sun white.jpg
Symbol[q] Sun symbol.svg
Mean distance
from the Galactic Center
km
light years
~2.5×1017
~26,000
Mean radius km
:E[f]
695,508
109.3
Surface area km2
:E[f]
6.0877×1012
11,990
Volume km3
:E[f]
1.4122×1018
1,300,000
Mass kg
:E[f]
1.9855×1030
332,978.9
Gravitational parameter m3/s2 1.327×1020
Density g/cm3 1.409
Equatorial gravity m/s2 274.0
Escape velocity km/s 617.7
Rotation period days[g] 25.38
Orbital period about Galactic Center[4] million years 225–250
Mean orbital speed[4] km/s ~220
Axial tilt[i] to the ecliptic deg. 7.25
Axial tilt[i] to the galactic plane deg. 67.23
Mean surface temperature K 5,778
Mean coronal temperature[5] K 1–2×106
Photospheric composition HHeOCFeS

Planets

Key
*
Terrestrial planet
°
Gas giant

Ice giant

The 2006 International Astronomical Union (IAU) defines a planet as a body in orbit around the Sun that was large enough to have achieved hydrostatic equilibrium and to have "cleared the neighbourhood around its orbit".[6] The practical meaning of "cleared the neighborhood" is that a planet is comparatively massive enough for its gravitation to control the orbits of all objects in its vicinity. By the IAU's definition, there are eight planets in the Solar System; four terrestrial planets (Mercury, Venus, Earth and Mars) and four giant planets, which can be divided further into two gas giants (Jupiter and Saturn) and two ice giants (Uranus and Neptune). When excluding the Sun, the four giant planets account for more than 99% of the mass of the Solar System.

  *Mercury[7][8][9] *Venus[10][11][9] *Earth[12][13][9] *Mars[14][15][9] °Jupiter[16][17][9] °Saturn[18][19][9] Uranus[20][21] Neptune[22][23][9]
  Mercury in true color.jpg PIA23791-Venus-NewlyProcessedView-20200608.jpg The Earth seen from Apollo 17.jpg OSIRIS Mars true color.jpg Jupiter and its shrunken Great Red Spot.jpg Saturn during Equinox.jpg Uranus.jpg Neptune - Voyager 2 (29347980845) flatten crop.jpg
Symbol[q] Mercury symbol.svg Venus symbol.svg Earth symbol.svg Mars symbol.svg Jupiter symbol.svg Saturn symbol.svg Uranus symbol.svg or Uranus Herschel symbol.svg Neptune symbol.svg
Mean distance
from the Sun
km
AU
57,909,175
0.38709893
108,208,930
0.72333199
149,597,890
1.00000011
227,936,640
1.52366231
778,412,010
5.20336301
1,426,725,400
9.53707032
2,870,972,200
19.19126393
4,498,252,900
30.06896348
Equatorial radius km
:E[f]
2,440.53
0.3826
6,051.8
0.9488
6,378.1366
1
3,396.19
0.53247
71,492
11.209
60,268
9.449
25,559
4.007
24,764
3.883
Surface area km2
:E[f]
75,000,000
0.1471
460,000,000
0.9020
510,000,000
1
140,000,000
0.2745
64,000,000,000
125.5
44,000,000,000
86.27
8,100,000,000
15.88
7,700,000,000
15.10
Volume km3
:E[f]
6.083×1010
0.056
9.28×1011
0.857
1.083×1012
1
1.6318×1011
0.151
1.431×1015
1,321.3
8.27×1014
763.62
6.834×1013
63.102
6.254×1013
57.747
Mass kg
:E[f]
3.302×1023
0.055
4.8690×1024
0.815
5.972×1024
1
6.4191×1023
0.107
1.8987×1027
318
5.6851×1026
95
8.6849×1025
14.5
1.0244×1026
17
Gravitational parameter m3/s2 2.203×1013 3.249×1014 3.986×1014 4.283×1013 1.267×1017 3.793×1016 5.794×1015 6.837×1015
Density g/cm3 5.43 5.24 5.52 3.940 1.33 0.70 1.30 1.76
Equatorial gravity m/s2 3.70 8.87 9.8 3.71 24.79 10.44 8.87 11.15
Escape velocity km/s 4.25 10.36 11.18 5.02 59.54 35.49 21.29 23.71
Rotation period[g] days 58.646225 243.0187 0.99726968 1.02595675 0.41354 0.44401 0.71833 0.67125
Orbital period[g] days
years
87.969
0.2408467
224.701
0.61519726
365.256363
1.0000174
686.971
1.8808476
4,332.59
11.862615
10,759.22
29.447498
30,688.5
84.016846
60,182
164.79132
Mean orbital speed km/s 47.8725 35.0214 29.7859 24.1309 13.0697 9.6724 6.8352 5.4778
Eccentricity 0.20563069 0.00677323 0.01671022 0.09341233 0.04839266 0.05415060 0.04716771 0.00858587
Inclination[f] deg. 7.00 3.39 0[12] 1.85 1.31 2.48 0.76 1.77
Axial tilt[i] deg. 0.0 177.3[h] 23.44 25.19 3.12 26.73 97.86[h] 28.32
Mean surface temperature K 440–100 730 287 227 152 [j] 134 [j] 76 [j] 73 [j]
Mean air temperature[k] K 288 165 135 76 73
Atmospheric composition HeNa+
K+ 
CO2N2, SO2 N2O2, Ar, CO2 CO2, N2
Ar
H2, He H2, He H2, He
CH4
H2, He
CH4
Number of known moons[v] 0 0 1 2 79 82 27 14
Rings? No No No No Yes Yes Yes Yes
Planetary discriminant[l][o] 9.1×104 1.35×106 1.7×106 1.8×105 6.25×105 1.9×105 2.9×104 2.4×104

Dwarf planets

Key

asteroid belt

trans-Neptunian

Dwarf planets are bodies that are massive and warm enough to have achieved hydrostatic equilibrium, but have not cleared their neighbourhoods of similar objects. Since 2008, there have been five dwarf planets recognized by the IAU, though of these only Pluto and Ceres, which orbits in the asteroid belt between the orbits of Mars and Jupiter, has been confirmed.[ae] The others all orbit beyond Neptune.

Ceres[24] Pluto[25][26] Haumea[27][28][29] Makemake[30][31] Eris[32]
Ceres - RC3 - Haulani Crater (22381131691) (cropped).jpg Pluto in True Color - High-Res.jpg Haumea Hubble.png Makemake moon Hubble image with legend (cropped).jpg Eris and dysnomia2.jpg
Symbol[q] Ceres symbol.svg Pluto symbol.svg or Pluto bident symbol.svg Haumea symbol (Moskowitz, fixed width).svg Makemake symbol (Moskowitz, fixed width).svg Eris symbol (Moskowitz, fixed width).svg
Minor planet number 1 134340 136108 136472 136199
Mean distance
from the Sun
km
AU
413,700,000
2.766
5,906,380,000
39.482
6,484,000,000
43.335
6,850,000,000
45.792
10,210,000,000
67.668
Mean radius km
:E[f]
473
0.0742
1,188.3[9]
0.186
816
(2100 × 1680 × 1074)
0.13[33][34]
715
0.11[35]
1,163
0.18[36]
Volume km3
:E[f]
4.21×108
0.00039[b]
6.99×109
0.0065
1.98×109
0.0018
1.7×109
0.0016[b]
6.59×109
0.0061[b]
Surface area km2
:E[f]
2,770,000
0.0054[a]
17,700,000
0.035
8,140,000
0.016[z]
6,900,000
0.0135[a]
17,000,000
0.0333[a]
Mass kg
:E[f]
9.39×1020
0.00016
1.30×1022
0.0022
4.01 ± 0.04×1021
0.0007[37]
< 4.4 ×1021

< 0.0007

1.65×1022
0.0028
Gravitational parameter m3/s2 6.263 × 1010 8.710 × 1011 2.674 × 1011 < 2.937 × 1011 1.108 × 1012
Density g/cm3 2.16 1.87 2.02[33] 2.10 2.43
Equatorial gravity m/s2 0.27[d] 0.62 0.63[d] < 0.57 0.82[d]
Escape velocity km/s[e] 0.51 1.21 0.91 < 0.91 1.37
Rotation period[g] days 0.3781 6.3872 0.1631 0.9511 14.560
Orbital period[g] years 4.599 247.9 283.8 306.2 559
Mean orbital speed km/s 17.882 4.75 4.48[o] 4.40[o] 3.44[n]
Eccentricity 0.080 0.249 0.195 0.161 0.436
Inclination[f] deg. 10.59 17.14 28.21 28.98 44.04
Axial tilt[i] deg. 4 119.6[h] ≈126 ? ≈78
Mean surface temperature[w] K 167[38] 40[39] <50[40] 30 30
Atmospheric composition H2O N2, CH4, CO ? N2, CH4[41] N2, CH4[42]
Number of known moons[v] 0 5 2[43] 1[44] 1[45]
Planetary discriminant[l][o] 0.33 0.077 0.023 0.02 0.10

Astronomers generally agree that several other trans-Neptunian objects may be large enough to be dwarf planets, given current uncertainties. However, there has been disagreement on the required size. Early speculations were based on the small moons of the giant planets, which attain roundness around a 400 km threshold in diameter.[46] However, these moons are at higher temperatures than TNOs and are icier than TNOs are likely to be.

Many TNOs in the 400–1000 km size range are dark and low-density bodies, like 174567 Varda, 229762 Gǃkúnǁʼhòmdímà, or (55637) 2002 UX25. They have densities too low to be solid mixtures of ice and rock, which the larger TNOs are. It was once considered that this was because they were predominantly icy like some moons of Saturn, but TNOs both above and below this size range contain significant rock fractions, and William Grundy et al. pointed out that there is no evolutionary mechanism that would allow large and small TNOs to be rocky while medium ones would not be. They hypothesise instead that medium-sized TNOs are also rocky, and have low densities because they return internal porosity from their formation, and hence are not planetary bodies (as planetary bodies have sufficient gravitation to collapse out such porosity). Ice–rock mixtures at Kuiper belt temperatures are expected to be strong enough to support significant open spaces in objects up to 700 km diameter. At 900 km diameter, the interior might eventually start to collapse, but the process might not reach the surface, which would remain cold and uncompressed. (As collapsing out porosity would shrink an object, likely differentiated objects now in this size range like Orcus were probably once even larger.) Dark surfaces indicate that a body has never been resurfaced (in contrast to Orcus and Charon with bright, relatively clean water ice on their surfaces), and thus that it has at most incompletely differentiated (and might not have differentiated at all). If this assessment is correct, then only the largest few TNOs could be dwarf planets, with a transition taking place around 900–1000 km diameter rather than 400 km.[47]

The only known TNOs that have a diameter greater than 900 km, but have not been officially recognised by the IAU are dwarf planets, are Quaoar, Orcus, Sedna, and Gonggong. Quaoar, Orcus, and Gonggong have moons that have allowed their mass and density to be determined using Kepler's third law, and they are either bright enough (Orcus) to suggest resurfacing and thus planetary geology at least at some point in their past, or are dense enough (Quaoar and Gonggong) that they are clearly solid bodies and thus at least potentially dwarf planets. Sedna, which is bright but has unknown density, has been included as a strong additional candidate.

Orcus[48] Quaoar[49] Gonggong[50] Sedna[51]
Orcus-vanth hst2.jpg Quaoar-weywot hst.jpg 2007 OR10 and its moon.png Sedna PRC2004-14d.jpg
Symbol[q] Orcus symbol (Moskowitz, fixed width).svg Quaoar symbol (Moskowitz, fixed width).svg Gonggong symbol (Moskowitz, fixed width).svg Sedna symbol (Moskowitz, fixed width).svg
Minor-planet number 90482 50000 225088 90377
Semi-major axis km
AU
5,896,946,000
39.419
6,535,930,000
43.69
10,072,433,340
67.33
78,668,000,000
525.86
Mean radius[s] km
:E[f]
458.5[52]
0.0720
560.5[53]
0.0870
615[54]
0.0982
497.5[55]
0.0780
Surface area[a] km2
:E[f]
2,641,700
0.005179
3,948,000
0.007741
4,932,300
0.009671
3,110,200
0.006098
Volume[b] km3
:E[f]
403,744,500
0.000373
737,591,000
0.000681
1,030,034,600
0.000951
515,784,000
0.000476
Mass[t] kg
:E[f]
6.32×1020[56]
0.0001
1.41×1021[57]
0.0003
1.75×1021[54]
0.0003
?
Density[t] g/cm3 1.5±0.3[56] 1.99±0.46[57] 1.74±0.16 ?
Equatorial gravity[d] m/s2 0.27 0.24 0.285 ?
Escape velocity[e] km/s 0.50 0.45 0.604 ?
Rotation period[g] days ? 0.3683 0.9333 0.4280[58]
Orbital period[g] years 247.49 287.97 552.52 12,059
Mean orbital speed km/s 4.68 4.52 3.63 1.04
Eccentricity 0.226 0.038 0.506 0.855
Inclination[f] deg. 20.59 7.99 30.74 11.93
Mean surface temperature[w] K ~42 ~41 ~30 ~12
Number of known moons 1[59] 1[60] 1 0
Planetary discriminant[l][o] 0.003 0.0015 <0.1 ?[x]
Absolute magnitude (H) 2.3 2.71 1.8 1.5

Satellites

Key
🜨
Satellite of Earth

Satellite of Jupiter

Satellite of Saturn

Satellite of Uranus

Satellite of Neptune

Satellite of Pluto

There are at least 19 natural satellites in the Solar System that are known to be massive enough to be close to hydrostatic equilibrium: seven of Saturn, five of Uranus, four of Jupiter, and one each of Earth, Neptune, and Pluto. Alan Stern calls these satellite planets, although the term major moon is more common.

Several of these were once in equilibrium but are no longer: these include Earth's moon[61] and all of the moons listed for Saturn apart from Titan and Rhea.[62] The status of the moons of Uranus and Pluto are uncertain.[63] Other moons that were once in equilibrium but are no longer very round, such as Saturn's Phoebe, are not included. The satellites of Eris (Dysnomia) and Orcus (Vanth) are in this size range, but are not included as little is known about them (for example, their densities are not known). They are dark bodies that are in the size range which should allow for internal porosity.[47]

Satellites are listed first in order from the Sun, and second in order from their parent body.

🜨Moon[64] Io[65] Europa[66] Ganymede[67] Callisto[68] Mimas[p] Enceladus[p] Tethys[p] Dione[p] Rhea[p]
FullMoon2010.jpg Io highest resolution true color.jpg Europa-moon-with-margins.jpg Ganymede - Perijove 34 Composite.png Callisto.jpg Mimas Cassini.jpg PIA17202 - Approaching Enceladus.jpg PIA18317-SaturnMoon-Tethys-Cassini-20150411.jpg Dione in natural light (cropped).jpg PIA07763 Rhea full globe5.jpg
Symbol[q] Moon symbol decrescent.svg
Mean distance
from primary:
km 384,399 421,600 670,900 1,070,400 1,882,700 185,520 237,948 294,619 377,396 527,108
Mean radius km
:E[f]
1,737.1
0.272
1,815
0.285
1,569
0.246
2,634.1
0.413
2,410.3
0.378
198.30
0.031
252.1
0.04
533
0.084
561.7
0.088
764.3
0.12
Surface area[a] 1×106 km2 37.93 41.910 30.9 87.0 73 0.49 0.799 3.57 3.965 7.337
Volume[b] 1×109 km3 22 25.3 15.9 76 59 0.033 0.067 0.63 0.8 1.9
Mass 1×1022 kg 7.3477 8.94 4.80 14.819 10.758 0.00375 0.0108 0.06174 0.1095 0.2306
Density[c] g/cm3 3.3464 3.528 3.01 1.936 1.83 1.15 1.61 0.98 1.48 1.23
Equatorial gravity[d] m/s2 1.622 1.796 1.314 1.428 1.235 0.0636 0.111 0.145 0.231 0.264
Escape velocity[e] km/s 2.38 2.56 2.025 2.741 2.440 0.159 0.239 0.393 0.510 0.635
Rotation period days[g] 27.321582
(sync)[m]
1.7691378
(sync)
3.551181
(sync)
7.154553
(sync)
16.68902
(sync)
0.942422
(sync)
1.370218
(sync)
1.887802
(sync)
2.736915
(sync)
4.518212
(sync)
Orbital period about primary days[g] 27.32158 1.769138 3.551181 7.154553 16.68902 0.942422 1.370218 1.887802 2.736915 4.518212
Mean orbital speed[o] km/s 1.022 17.34 13.740 10.880 8.204 14.32 12.63 11.35 10.03 8.48
Eccentricity 0.0549 0.0041 0.009 0.0013 0.0074 0.0202 0.0047 0.02 0.002 0.001
Inclination to primary's equator deg. 18.29–28.58 0.04 0.47 1.85 0.2 1.51 0.02 1.51 0.019 0.345
Axial tilt[i][u] deg. 6.68 0 0 0–0.33[69] 0 0 0 0 0 0
Mean surface temperature[w] K 220 130 102 110[70] 134 64 75 64 87 76
Atmospheric composition ArHe
NaKH
SO2[71] O2[72] O2[73] O2CO2[74] H2O, N2
CO2, CH4[75]
Rings? No No No No No No No No No Yes?
Titan[p] Iapetus[p] Miranda[r] Ariel[r] Umbriel[r] Titania[r] Oberon[r] Triton[76] Charon[25]
Titan in true color.jpg Iapetus true.jpg Miranda.jpg Ariel (moon).jpg PIA00040 Umbrielx2.47.jpg Titania (moon) color cropped.jpg Voyager 2 picture of Oberon.jpg Triton2.jpg Charon in True Color - High-Res.jpg
Mean distance
from primary:
km 1,221,870 3,560,820 129,390 190,900 266,000 436,300 583,519 354,759 17,536
Mean radius km
:E[f]
2,576
0.404
735.60
0.115
235.8
0.037
578.9
0.091
584.7
0.092
788.9
0.124
761.4
0.119
1,353.4
0.212
603.5
0.095
Surface area[a] 1×106 km2 83.0 6.7 0.70 4.211 4.296 7.82 7.285 23.018 4.580
Volume[b] 1×109 km3 71.6 1.67 0.055 0.81 0.84 2.06 1.85 10 0.92
Mass 1×1022 kg 13.452 0.18053 0.00659 0.135 0.12 0.35 0.3014 2.14 0.152
Density[c] g/cm3 1.88 1.08 1.20 1.67 1.40 1.72 1.63 2.061 1.65
Equatorial gravity[d] m/s2 1.35 0.22 0.08 0.27 0.23 0.39 0.35 0.78 0.28
Escape velocity[e] km/s 2.64 0.57 0.19 0.56 0.52 0.77 0.73 1.46 0.58
Rotation period days[g] 15.945
(sync)[m]
79.322
(sync)
1.414
(sync)
2.52
(sync)
4.144
(sync)
8.706
(sync)
13.46
(sync)
5.877
(sync)
6.387
(sync)
Orbital period about primary days 15.945 79.322 1.4135 2.520 4.144 8.706 13.46 5.877 6.387
Mean orbital speed[o] km/s 5.57 3.265 6.657 5.50898 4.66797 3.644 3.152 4.39 0.2
Eccentricity 0.0288 0.0286 0.0013 0.0012 0.005 0.0011 0.0014 0.00002 0.0022
Inclination to primary's equator deg. 0.33 14.72 4.22 0.31 0.36 0.14 0.10 157[h] 0.001
Axial tilt[i][u] deg. 0 0 0 0 0 0 0 0 0
Mean surface temperature[w] K 93.7[77] 130 59 58 61 60 61 38[78] 53
Atmospheric composition N2, CH4[79] N2, CH4[80]

See also

Notes

Unless otherwise cited:[ac]

  1. ^ The planetary discriminant for the planets is taken from material published by Stephen Soter.[81] Planetary discriminants for Ceres, Pluto and Eris taken from Soter, 2006. Planetary discriminants of all other bodies calculated from the Kuiper belt mass estimate given by Lorenzo Iorio.[82]
  2. ^ Saturn satellite info taken from NASA Saturnian Satellite Fact Sheet.[83]
  3. ^ With the exception of the Sun and Earth symbols, astronomical symbols are mostly used by astrologers today; although occasional use of the other planet symbols (and Pluto) in astronomical contexts still exists,[84] it is officially discouraged.[85] Astronomical symbols for the Sun, the planets (first symbol for Uranus), and the Moon, as well as the first symbol for Pluto were taken from NASA Solar System Exploration.[86] The other symbols are even rarer in modern astronomy. The symbol for Ceres was taken from material published by James L. Hilton; it was used astronomically when Ceres was thought to be a major planet, and continues to be used today in astrology. The second symbol for Uranus was also taken from there.[87] The symbols for Haumea, Makemake, and Eris appear in a NASA JPL infographic, as does the second symbol for Pluto; they are otherwise mostly astrological symbols.[88] The symbols for Quaoar, Sedna, Orcus, and Gonggong were taken from the astrology progam Astrolog; so far they have only been used in astrology.[89] The Moon is the only natural satellite with a standard astronomical symbol. Symbols have been proposed for the other bodies on this list, but have yet to receive widespread adoption amongst astronomers or astrologers.
  4. ^ Uranus satellite info taken from NASA Uranian Satellite Fact Sheet.[90]
  5. ^ Radii for plutoid candidates taken from material published by John A. Stansberry et al.[36]
  6. ^ Axial tilts for most satellites assumed to be zero in accordance with the Explanatory Supplement to the Astronomical Almanac: "In the absence of other information, the axis of rotation is assumed to be normal to the mean orbital plane."[91]
  7. ^ Natural satellite numbers taken from material published by Scott S. Sheppard.[92]

Manual calculations (unless otherwise cited)

  1. ^ Surface area A derived from the radius using , assuming sphericity.
  2. ^ Volume V derived from the radius using , assuming sphericity.
  3. ^ Density derived from the mass divided by the volume.
  4. ^ Surface gravity derived from the mass m, the gravitational constant G and the radius r: Gm/r2.
  5. ^ Escape velocity derived from the mass m, the gravitational constant G and the radius r: (2Gm)/r.
  6. ^ Orbital speed is calculated using the mean orbital radius and the orbital period, assuming a circular orbit.
  7. ^ Assuming a density of 2.0
  8. ^ Calculated using the formula where Teff = 54.8 K at 52 AU, is the geometric albedo, q = 0.8 is the phase integral, and is the distance from the Sun in AU. This formula is a simplified version of that in section 2.2 of Stansberry et al., 2007,[36] where emissivity and beaming parameter were assumed equal unity, and was replaced with 4 accounting for the difference between circle and sphere. All parameters mentioned above were taken from the same paper.
  9. ^ Calculated using the formula , where H is the absolute magnitude, p is the geometric albedo and D is the diameter in km, and assuming an albedo of 0.15, as per Dan Bruton.[93]
  10. ^ Mass derived from the density multiplied by the volume.

Individual calculations

  1. ^ Derived from density
  2. ^ Surface area was calculated using the formula for a scalene ellipsoid:
    where is the modular angle, or angular eccentricity; and , are the incomplete elliptic integrals of the first and second kind, respectively. The values 980 km, 759 km, and 498 km were used for a, b, and c respectively.

Other notes

  1. ^ Relative to Earth
  2. ^ Sidereal
  3. ^ Retrograde
  4. ^ The inclination of the body's equator from its orbit.
  5. ^ At pressure of 1 bar
  6. ^ At sea level
  7. ^ The ratio between the mass of the object and those in its immediate neighborhood. Used to distinguish between a planet and a dwarf planet.
  8. ^ This object's rotation is synchronous with its orbital period, meaning that it only ever shows one face to its primary.
  9. ^ Objects' planetary discriminants based on their similar orbits to Eris. Sedna's population is currently too little-known for a planetary discriminant to be determined.
  10. ^ Proteus average diameter: 210 km;[76] Mimas average diameter: 199 km[83]
  11. ^ "Unless otherwise cited" means that the information contained in the citation is applicable to an entire line or column of a chart, unless another citation specifically notes otherwise.
  12. ^ Gravitational measurements by the Dawn orbiter have demonstrated that Ceres is in hydrostatic equilibrium.[94] None of the other putative dwarf planets have been observed this closely, though Pluto and Eris are universally assumed to be in equilibrium as well.

References

  1. ^ Woolfson, Michael Mark (2000). "The Origin and Evolution of the Solar System". Astronomy & Geophysics. 41 (1): 1.12–1.19. Bibcode:2000A&G....41a..12W. doi:10.1046/j.1468-4004.2000.00012.x.
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