List of gravitationally rounded objects of the Solar System

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In 2006, the International Astronomical Union (IAU) defined 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.[1] An object in hydrostatic equilibrium is one that is large enough for its gravity to have overcome its internal rigidity, and so relax into a rounded (ellipsoidal) shape. 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. Those objects in orbit around the Sun that have achieved hydrostatic equilibrium but have not cleared their neighborhoods are called dwarf planets, and the remainder are termed small Solar System bodies. In addition, the Sun itself and a dozen or so natural satellites are also massive enough to have achieved hydrostatic equilibrium.[2] Apart from the Sun, these bodies are included in the term planetary-mass object, or planemo. All known planetary-mass objects in the Solar System, as well as the Sun, are listed below, along with a sample of the largest objects whose shape has yet to be accurately determined. The Sun's orbital characteristics are listed in relation to the Galactic Center. All other objects are listed in order of their distance from the Sun.

Sun[edit]

The Sun is a G-type main-sequence star. It contains almost 99.9 percent of all the mass in the Solar System.[3]

Sun[4]
The Sun by the Atmospheric Imaging Assembly of NASA's Solar Dynamics Observatory - 20100819.jpg
Astronomical symbol[q] Sun
Mean distance
from Galactic Center
km
light years
~2.5×1017
~26,000
Mean radius km
 :E[f]
696,000
109
Surface area km2
 :E[f]
6.0877×1012
11,990
Volume km3
 :E[f]
1.4122×1018
1,300,000
Mass kg
 :E[f]
1.9891×1030
332,946
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[5] million years 225–250
Mean orbital speed[5] 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[6] K 1–2×106
Photospheric composition HHeOCFeS

Planets[edit]

Key
*
terrestrial planet
°
gas giant

Planets are both large enough to have achieved hydrostatic equilibrium and have cleared their neighborhoods of similar objects. There are four terrestrial planets and four gas giants in the Solar System. The latter combined comprise more than 99 percent of the mass in the Solar System excluding that of the Sun.

*Mercury[7] *Venus[8] *Earth[9] *Mars[10] °Jupiter[11] °Saturn[12] °Uranus[13] °Neptune[14]
Mercury in color - Prockter07 centered.jpg Venus-real color.jpg The Earth seen from Apollo 17.jpg Mars Valles Marineris.jpeg Jupiter by Cassini-Huygens.jpg Saturn closeup.jpg Uranus2.jpg Neptune.jpg
Astronomical symbol[q] Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
Mean distance
from 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]
2,439.64
0.3825
6,051.59
0.9488
6,378.1
1
3,397.00
0.53226
71,492.68
11.209
60,267.14
9.449
25,557.25
4.007
24,766.36
3.883
Surface area km²
 :E[f]
75,000,000
0.1471
460,000,000
0.9010
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
0.87
1.083×1012
1
1.6318×1011
0.151
1.431×1015
1,321.3
8.27×1014
763.59
6.834×1013
63.086
6.254×1013
57.74
Mass kg
 :E[f]
3.302×1023
0.055
4.8690×1024
0.815
5.9742×1024
1
6.4191×1023
0.107
1.8987×1027
318
5.6851×1026
95
8.6849×1025
14
1.0244×1026
17
Density g/cm3 5.43 5.24 5.515 3.940 1.33 0.70 1.30 1.76
Equatorial gravity m/s2 3.70 8.87 9.81 3.71 23.12 10.44 8.69 11.00
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[h] 0.99726968 1.02595675 0.41354 0.44401 −0.71833[h] 0.67125
Orbital period[g] years 0.2408467 0.61519726 1.0000174 1.8808476 11.862615 29.447498 84.016846 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[9] 1.85 1.31 2.48 0.76 1.77
Axial tilt[i] deg. 0.0 177.3 23.44 25.19 3.12 26.73 97.86 29.58
Mean surface temperature K 440–100 730 287 227 152 [j] 134 [j] 72 [j] 76 [j]
Mean air temperature[k] K 288 165 135 73 76
Atmospheric composition He  Na+  P+  CO2  N2 N2  O2 CO2  N2  Ar H2  He H2  He H2  He  CH4 H2  He  CH4
Number of known moons[v] 0 0 1 2 67 62 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

Satellites[edit]

Key

Satellite of Earth

Satellite of Jupiter
$
Satellite of Saturn

Satellite of Uranus

Satellite of Neptune

Satellite of Pluto

There are 19 natural satellites in the Solar System that are known to be massive enough to be close to hydrostatic equilibrium, which Alan Stern calls satellite planets. However, several of these were once in equilibrium but are no longer: these include all of the moons listed for Saturn apart from Titan and Rhea. Other moons that were once in equilibrium but are no longer very round, such as Saturn's Phoebe, are not included. Satellites are listed first in order from the Sun, and second in order from their parent body.

Moon[15] Io[16] Europa[17] Ganymede[18] Callisto[19] $Mimas[p] $Enceladus[p] $Tethys[p] $Dione[p] $Rhea[p]
FullMoon2010.jpg Io highest resolution true color.jpg Europa-moon.jpg Noaa ganymede.jpg Callisto.jpg Mimas moon.jpg Enceladus north.jpg Inset-sat tethys-large.jpg Dione.jpg Rhea (moon) thumb.jpg
Astronomical symbol[q] Moon
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
0.273
1,815
0.286
1,569
0.245
2,634.1
0.413
2,410.3
0.378
198.30
0.031
252.1
0.04
533
0.083
561.7
0.088
764.3
0.12
Surface area[a] km²
 :E[f]
37,930,000
0.074
41,910,000
0.082
30,900,000
0.061
87,000,000
0.171
73,000,000
0.143
490,000
0.001
799,000
0.0016
3,570,000
0.007
3,965,000
0.0078
7,337,000
0.0144
Volume[b] km3
 :E[f]
2.2×1010
0.02
2.53×1010
0.02
1.59×1010
0.07
7.6×1010
0.15
5.9×1010
0.05
3.3×107
0.00003
6.7×107
0.00006
6.3×108
0.0006
7.4×108
0.0007
1.9 ×109
0.0017
Mass kg
 :E[f]
7.3477×1022
0.0123
8.94×1022
0.015
4.80×1022
0.008
1.4819×1023
0.025
1.0758×1023
0.018
3.75×1019
0.000006
1.08×1020
0.000018
6.174×1020
0.00132
1.095×1021
0.0003
2.306×1021
0.0004
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[20] 0 0 0 0 0 0
Mean surface temperature[w] K 220 130 102 110[21] 134 64 75 64 87 76
Atmospheric composition H  He Na+  K+ Ar SO2[22] O2[23] O2[24] O2  CO2[25] H2O, N2, CO2, CH4[26]
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[27] Charon[28]
Titan in natural color Cassini.jpg Iapetus by Voyager 2 - enhanced.jpg Miranda.jpg Ariel (moon).jpg Umbriel moon 1.gif Titania (moon) color cropped.jpg Voyager 2 picture of Oberon.jpg Triton Voyager 2.jpg Charon.png
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
1353.4
0.212
603.5
0.095
Surface area[a] km²
 :E[f]
83,000,000
0.163
6,700,000
0.013
700,000
0.0014
4,211,300
0.008
4,296,000
0.008
7,820,000
0.015
7,285,000
0.014
23,018,000
0.045
4,580,000
0.009
Volume[b] km3
 :E[f]
7.16×1010
0.066
1.67×109
0.0015
5.5×107
0.00005
8.1×108
0.0008
8.4×108
0.0008
2.06×109
0.0019
1.85×109
0.0017
1×1010
0.00958
9.2×108
0.00085
Mass kg
 :E[f]
1.3452×1023
0.023
1.8053×1021
0.0003
6.59×1019
0.00001
1.35×1021
0.00022
1.2×1021
0.0002
3.5×1021
0.0006
3.014×1021
0.00046
2.14×1022
0.00358
1.52×1021
0.00025
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[h] 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  ?
Axial tilt[i][u] deg. 0 0 0 0 0 0 0 0  ?
Mean surface temperature[w] K 93.7[29] 130 59 58 61 60 61 38 [30] 53
Atmospheric composition N2, CH4[31] N2, CH4[32]

IAU dwarf planets[edit]

Key

Ceres

plutoid

Dwarf planets are large enough to have achieved hydrostatic equilibrium, but have not cleared their neighbourhoods of similar objects. There are currently five dwarf planets recognized by the IAU in this category. Ceres orbits in the asteroid belt, between the orbits of Mars and Jupiter. The others orbit beyond Neptune and are sub-classified as plutoids.

Ceres[33] Pluto[28] Haumea[34] Makemake[35] Eris[36]
Ceres optimized.jpg Pluto-map-hs-2010-06-d270.jpg 2003EL61art.jpg 2005FY9art.jpg Eris and dysnomia2.jpg
Astronomical symbol[q] Ceres Pluto
Minor planet number 1 134340 136108 136472 136199
Mean distance
from 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]
471
0.0738
1,184
0.180
650 (960×770×495)
0.10[37][38]
715±7
0.11[39]
1,163
0.19[40]>
Volume km3
 :E[f]
4.37×108
0.0005[b]
6.33×109
0.007
1.5×109
0.001
1.5×109
0.001[b]
7.23×109
0.008[b]
Surface area km²
 :E[f]
2,800,000
0.0055[a]
17,000,000
0.0333
6,800,000
0.0133[z]
6,400,000
0.013[a]
17,000,000
0.0333[a]
Mass kg
 :E[f]
9.5×1020
0.00016
1.3×1022
0.0022
4.01 ± 0.04×1021
0.0007[41]
>2.1×1021
>0.0003[ad]
1.7×1022
0.0028[42]
Density g/cm3 2.08 2.0 2.6[37] >1.4[39] 2.25[c]
Equatorial gravity m/s2 0.27[d] 0.60 0.63[d] >0.28[d] ~0.8[d]
Escape velocity km/s[e] 0.51 1.23 0.91 >0.6 1.37
Rotation period[g] days 0.3781 −6.38718[h] 0.167  ?  ?
Orbital period[g] years 4.599 247.92065 285.4 309.9 557
Mean orbital speed km/s 17.882 4.7490 4.484[o] 4.4[o] 3.436[n]
Eccentricity 0.080 0.24880766 0.18874 0.159 0.44177
Inclination[f] deg. 10.587 17.14175 28.19 28.96 44.187
Axial tilt[i] deg. 4 119.61  ?  ?  ?
Mean surface temperature[w] K 167[43] 40[44] <50[45] 30 30
Atmospheric composition H2O, O2 N2, CH4 N2, CH4.[46] N2, CH4[47]
Number of known moons[v] 0 5 2[48] 0[49] 1[50]
Planetary discriminant[l][o] 0.33 0.077 0.023 0.02 0.10

Most likely additional dwarf planets[edit]

These trans-Neptunian objects are theoretically large enough to be dwarf planets. Dozens more could have been included.[2] Both Quaoar and Orcus have known moons that have allowed the mass of the systems to be determined. Both are more massive than the 5×1020 kg recommendation of the IAU 2006 draft proposal as sufficient for classification as a dwarf planet.[51]

Orcus[52] Ixion[53] 2002 MS4[54] Salacia[55] Varuna[56] 2005 UQ513[57] Quaoar[58] 2007 OR10[59] 2007 UK126[60] Sedna[61]
Orcus nasa.jpg Ixion planetoid nasa.jpg Varuna artistic.png Quaoar PRC2002-17e.jpg 1880-CT MBrown SPOTLIGHT medium.jpg MinorPlanet-2007uk126-19970930.gif Artist's conception of Sedna.jpg
Minor-planet number 90482 28978 307261 120347 20000 202421 50000 225088 229762 90377
Semi-major axis km
AU
5,896,946,000
39.419
5,935,999,000
39.68
6,273,000,000
41.93
6,311,000,000
42.19
6,451,398,000
43.13
6,479,089,380
43.31
6,493,296,000
43.6
10,072,433,340
67.33
11,032,000,000
73.74
78,668,000,000
525.86
Mean radius[s] km
 :E[f]
473
0.0742
402
0.063
467[62]
0.073
427[63]
0.067
~350
0.055
460
0.072[aa]
422
0.066
~640
0.10
440
0.07[aa]
~500
0.08
Surface area[a] km²
 :E[f]
2,811,462
0.0055
2,030,775
0.00398
 ?  ? 1,091,000
0.00636
2,659,044
0.0052
2,237,870
0.00439
6,157,522
0.012
2,432,849
0.005
3,000,000
0.006
Volume[b] km3
 :E[f]
443,273,768
0.0004
272,123,951
0.0002
 ?  ? 549,135,785
0.0005
407,720,083
0.0003
314,793,649
0.0002
1,436,755,040
0.001
356,817,905
0.0002
500,000,000
0.0005
Mass[t] kg
 :E[f]
6.32×1020[64]
0.0001
5.4×1020
0.00009
 ? 4.5×1020[65]
0.000075
5.5×1020
0.00009
8.2×1020
0.0001
(1.3–1.9)×1021[66]
0.0004
2.9×1021
0.0005
7.1×1020
0.0001
1×1021
0.00016
Density[t] g/cm3 1.5±0.3[64] 2.0  ? 1.16[65] 0.9992[67] 2.0 >2.8[66] 2.0 2.0 2.0
Equatorial gravity[d] m/s2 0.27 0.22  ? 0.11 0.14 0.26 0.24 <0.39 0.25 <0.5
Escape velocity[e] km/s 0.50 0.42  ? 0.43 0.38 0.49 0.45 <0.74 0.46 <1.0
Rotation period[g] days  ?  ?  ? 0.25 0.13216[67]  ?  ?  ?  ? 0.42[68]
Orbital period[g] years 247.492 249.95 271.53 274.03 283.20 285.12 287.97 552.52 633.28 12,059.06
Mean orbital speed km/s 4.68 4.66  ?  ? 4.53 4.52 4.52 3.63 3.25 1.04
Eccentricity 0.22552 0.242 0.148 0.10312 0.051 0.145 0.038 0.5 0.490 0.855
Inclination[f] deg. 22.5 19.6 17.693 23.9396 17.2 25.69 8 30.7 23.37 11.93
Mean surface temperature[w] K ~42 ~43  ?  ? ~43 ~41 ~41 ~30 ~32 ~12
Number of known moons 1[69] 0 0 1 0 0 1[70] 0 1[71] 0
Planetary discriminant[l][o] 0.003 0.0027 <0.1 <0.1 0.0027 0.003 0.0015 <0.1 0.036[x]  ?[x]
Absolute magnitude (H) 2.30 3.20 3.7 4.2 3.70 3.40 2.71 1.7 3.40 1.58

Notes[edit]

Unless otherwise cited:[ac][edit]

  1. ^ The planetary discriminant for the planets is taken from material published by Stephen Soter.[72] 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.[73]
  2. ^ Saturn satellite info taken from NASA Saturnian Satellite Fact Sheet.[74]
  3. ^ Astronomical symbols for all listed objects except Ceres taken from NASA Solar System Exploration.[75] Symbol for Ceres was taken from material published by James L. Hilton.[76] The Moon is the only natural satellite with an astronomical symbol, and Pluto and Ceres the only dwarf planets.
  4. ^ Uranus satellite info taken from NASA Uranian Satellite Fact Sheet.[77]
  5. ^ Radii for plutoid candidates taken from material published by John Stansberry et al.[40]
  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."[78]
  7. ^ Natural satellite numbers taken from material published by Scott S. Sheppard.[79]

Manual calculations (unless otherwise cited)[edit]

  1. ^ Surface area A derived from the radius using \begin{smallmatrix}A=4\pi r^2 \end{smallmatrix}, assuming sphericity.
  2. ^ Volume V derived from the radius using \begin{smallmatrix}V=\frac{4}{3}\pi r^3 \end{smallmatrix}, 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: G*m/r2 .
  5. ^ Escape velocity derived from the mass m, the gravitational constant G and the radius r: sqrt((2*G*m)/r).
  6. ^ Orbital speed is calculated using the mean orbital radius and the orbital period, assuming a circular orbit.
  7. ^ Assuming Pluto's density of 2.0
  8. ^ Calculated using the formula \begin{smallmatrix}T\ =\ \frac{T_{\textrm{eff}}(1-qp_{\nu})^{1/4}}{\sqrt{2}}\sqrt{52/r},\end{smallmatrix} where Teff =54.8 K at 52 AU, p_{\nu} is the geometric albedo, q=0.8 is the phase integral, and r 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,[40] where emissivity and beaming parameter were assumed equal unity, and \pi 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 \begin{smallmatrix}D=\frac{1329}{\sqrt{p}}10^{-0.2H}\end{smallmatrix}, 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.[80]
  10. ^ Mass derived from the density multipied by the volume.

Individual calculations[edit]

  1. ^ Derived from density
  2. ^ Surface area was calculated using the formula for a scalene ellipsoid:
    \begin{smallmatrix}2\pi\left(c^2+b\sqrt{a^2-c^2}E(\alpha,m)+\frac{bc^2}{\sqrt{a^2-c^2}}F(\alpha,m)\right),\,\!\end{smallmatrix} where \begin{smallmatrix}\alpha=\arccos\left(\frac{c}{a}\right)\,\,\!\end{smallmatrix} is the modular angle, or angular eccentricity; \begin{smallmatrix}m=\frac{b^2-c^2}{b^2\sin(\alpha)^2}\,\!\end{smallmatrix} and \begin{smallmatrix}F(\alpha,m)\,\!\end{smallmatrix}, \begin{smallmatrix}E(\alpha,m)\,\!\end{smallmatrix} 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[edit]

  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;[27] Mimas average diameter: 199 km[74]
  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.

References[edit]

  1. ^ "IAU 2006 General Assembly: Result of the IAU Resolution votes" (Press release). International Astronomical Union (News Release – IAU0603). 2006-08-24. Retrieved 2007-12-31.  (orig link)
  2. ^ a b Mike Brown. "The Dwarf Planets". CalTech. Retrieved 2008-09-25. 
  3. ^ M Woolfson (2000). "The origin and evolution of the solar system". Astronomy & Geophysics 41 (1): 1.12. Bibcode:2000A&G....41a..12W. doi:10.1046/j.1468-4004.2000.00012.x. 
  4. ^ NASA Solar System exploration Sun factsheet and NASA Sun factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  5. ^ a b Stacy Leong (2002). "Period of the Sun's Orbit around the Galaxy (Cosmic Year)". In Glenn Elert (ed.). The Physics Factbook (self-published). Retrieved 2008-06-26. 
  6. ^ Markus J. Aschwanden (2007). "The Sun". In Lucy Ann McFadden, Paul R. Weissman, Torrence V. Johnsson. Encyclopedia of the Solar System. Academic Press. p. 80. 
  7. ^ NASA Mercury Fact Sheet and NASA Solar System Exploration Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  8. ^ NASA Venus Factsheet and NASA Solar System Exploration Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  9. ^ a b NASA Earth factsheet and NASA Solar System Exploration Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  10. ^ NASA Mars Factsheet and NASA Mars Solar System Exploration Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  11. ^ NASA Jupiter factsheet and NASA Solar System Exploration Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  12. ^ NASA Saturn factsheet and NASA Solar System Exploration Saturn Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  13. ^ NASA Uranus factsheet and NASA Solar System Exploration Uranus Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  14. ^ NASA Neptune factsheet and NASA Solar System Exploration Neptune Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  15. ^ NASA Moon factsheet and NASA Solar System Exploration Moon Factsheet NASA Retrieved on 2008-11-17 (unless otherwise cited)
  16. ^ "NASA Io Factsheet". NASA. Retrieved 2008-11-16.  (unless otherwise cited)
  17. ^ "NASA Europa Factsheet". NASA. Retrieved 2008-11-16.  (unless otherwise cited)
  18. ^ "NASA Ganymede Factsheet". NASA. Retrieved 2008-11-16.  (unless otherwise cited)
  19. ^ "NASA Callisto Factsheet". NASA. Retrieved 2008-11-16. 
  20. ^ Bruce G. Bills (2005). "Free and forced obliquities of the Galilean satellites of Jupiter". Icarus 175 (1): 233–247. Bibcode:2005Icar..175..233B. doi:10.1016/j.icarus.2004.10.028. 
  21. ^ GS Orton; G.R. Spencer, L.D. Travis, et al. (1996). "Galileo Photopolarimeter-radiometer observations of Jupiter and the Galilean Satellites". Science 274 (5286): 389–391. Bibcode:1996Sci...274..389O. doi:10.1126/science.274.5286.389. 
  22. ^ JC Pearl, et al. (1979). "Identification of gaseous SO2 and new upper limits for other gases on Io". Nature 288 (5725): 755. Bibcode:1979Natur.280..755P. doi:10.1038/280755a0. 
  23. ^ D.T. Hall et al.; Detection of an oxygen atmosphere on Jupiter's moon Europa, Nature, Vol. 373 1995, 677–679 (accessed 2006-15-04)
  24. ^ DT Hall, PD Feldman, MA McGrath, et al. (1998). "The Far-Ultraviolet Oxygen Airglow of Europa and Ganymede". The Astrophysical Journal 499 (1): 475–481. Bibcode:1998ApJ...499..475H. doi:10.1086/305604.  Retrieved on 2008-11-17.
  25. ^ Mao-Chang Liang, BF Lane, RT Pappalardo, et al. (2005). "Atmosphere of Callisto" (PDF). Journal of Geophysics Research 110 (E02003): E02003. Bibcode:2005JGRE..11002003L. doi:10.1029/2004JE002322.  Retrieved on 2008-11-17.
  26. ^ JH Waite, et al. (2006). "Cassini Ion and Neutral Mass Spectrometer: Enceladus Plume Composition and Structure". Science 311 (5766): 1419–1422. Bibcode:2006Sci...311.1419W. doi:10.1126/science.1121290. PMID 16527970.  Retrieved on 2008-11-17.
  27. ^ a b Triton info taken from NASA Neptunian Satellite Fact Sheet NASA Retrieved on 2009-01-18 (unless otherwise cited)
  28. ^ a b NASA Pluto factsheet and NASA Solar System Exploration Pluto Factsheet Retrieved on 2008-11-17 (unless otherwise cited)
  29. ^ C. A. Hasenkopf (2007). "Optical Properties of Titan Haze Laboratory Analogs Using Cavity Ring Down Spectroscopy". Workshop on Planetary Atmospheres. Retrieved 2007-10-16. 
  30. ^ Kimberly Tryka, Robert Brown, V. Anicich et al. (August 1993). "Spectroscopic Determination of the Phase Composition and Temperature of Nitrogen Ice on Triton". Science 261 (5122): 751–754. Bibcode:1993Sci...261..751T. doi:10.1126/science.261.5122.751. PMID 17757214. 
  31. ^ H. B. Niemann, et al. (2005). "The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe". Nature 438 (7069): 779–784. Bibcode:2005Natur.438..779N. doi:10.1038/nature04122. PMID 16319830. 
  32. ^ A L Broadfoot, S K Bertaux, J E Dessler et al. (1989-12-15). "Ultraviolet Spectrometer Observations of Neptune and Triton". Science 246 (4936): 1459–1466. Bibcode:1989Sci...246.1459B. doi:10.1126/science.246.4936.1459. PMID 17756000. 
  33. ^ "NASA Asteroid Factsheet". NASA. Retrieved 2008-11-17. 
  34. ^ (i)Alexandra C. Lockwood, Michael E. Brown, John Stansberry (2014). "The size and shape of the oblong dwarf planet Haumea". Earth, Moon and Planets. arXiv:1402.4456v1. 
    (ii)D. L. Rabinowitz, K. M. Barkume, M. E. Brown, H. G. Roe, M. Schwartz, S. W. Tourtellotte, C. A. Trujillo (2006). "Photometric Observations Constraining the Size, Shape, and Albedo of 2003 EL61, a Rapidly Rotating, Pluto-Sized Object in the Kuiper Belt". The Astrophysical Journal 639 (2): 1238–1251. arXiv:astro-ph/0509401. Bibcode:2006ApJ...639.1238R. doi:10.1086/499575. 
    (iii)"Jet Propulsion Laboratory Small-Body Database Browser: 136108 Haumea". NASA's Jet Propulsion Laboratory (2008-05-10 last obs). Retrieved 2008-11-13.  (unless otherwise cited)
  35. ^ (i)Marc W. Buie (2008-04-05). "Orbit Fit and Astrometric record for 136472". SwRI (Space Science Department). Retrieved 2008-07-13. 
    (ii)"NASA Small Bodies Database Browser: 136472 Makemake (2005 FY9)". NASA JPL. Retrieved 2008-10-03.  (unless otherwise cited)
  36. ^ "NASA Small Body Database Browser: Eris". NASA JPL. Retrieved 2008-11-13.  (unless otherwise cited)
  37. ^ a b Alexandra C. Lockwood, Michael E. Brown, John Stansberry (2014). "The size and shape of the oblong dwarf planet Haumea". Earth, Moon and Planets. arXiv:1402.4456v1. 
  38. ^ E. Lollouch, et al.; Kiss, C.; Santos-Sanz, P.; Müller, T. G.; Fornasier, S.; Groussin, O.; Lacerda, P.; Ortiz, J. L.; Thirouin, A.; Delsanti, A.; Duffard, R.; Harris, A. W.; Henry, F.; Lim, T.; Moreno, R.; Mommert, M.; Mueller, M.; Protopapa, S.; Stansberry, J.; Trilling, D.; Vilenius, E.; Barucci, A.; Crovisier, J.; Doressoundiram, A.; Dotto, E.; Gutiérrez, P. J.; Hainaut, O.; Hartogh, P.; Hestroffer, D. et al. (2010). ""TNOs are cool": A survey of the trans-Neptunian region II. The thermal lightcurve of (136108) Haumea". Astronomy and Astrophysics 518: L147. arXiv:1006.0095. Bibcode:2010A&A...518L.147L. doi:10.1051/0004-6361/201014648. 
  39. ^ a b M.E. Brown, 2013, "On the size, shape, and density of dwarf planet Makemake"
  40. ^ a b c J. Stansberry, W. Grundy, M. Brown, et al.; Grundy; Brown; Cruikshank; Spencer; Trilling; Margot (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". The Solar System beyond Neptune (University of Arizona Press): 161. arXiv:astro-ph/0702538. Bibcode:2008ssbn.book..161S. 
  41. ^ M. E. Brown, A. H. Bouchez, D. L. Rabinowitz, R. Sari, C. A. Trujillo, M. A. van Dam, R. Campbell, J. Chin, S. Hartman, E. Johansson, R. Lafon, D. LeMignant, P. Stomski, D. Summers, P. L. Wizinowich (October 2005). "Keck Observatory laser guide star adaptive optics discovery and characterization of a satellite to large Kuiper belt object 2003 EL61". The Astrophysical Journal Letters 632 (L45): L45. Bibcode:2005ApJ...632L..45B. doi:10.1086/497641. 
  42. ^ Brown, Michael E.; Schaller, Emily L. (15 June 2007). "The Mass of Dwarf Planet Eris". Science 316 (5831): 1585. Bibcode:2007Sci...316.1585B. doi:10.1126/science.1139415. PMID 17569855.  edit
  43. ^ O. Saint-Pé; N. Combes; F. Rigaut (1993). "Ceres surface properties by high-resolution imaging from Earth". Icarus 105 (2): 271–281. Bibcode:1993Icar..105..271S. doi:10.1006/icar.1993.1125. 
  44. ^ T. Ker (2006). "Astronomers: Pluto colder than expected". Space.com (via CNN.com).  Retrieved on 2006-03-05.
  45. ^ Chadwick A. Trujillo, Michael E. Brown, Kristina Barkume, Emily Shaller, David L. Rabinowitz (February 2007). "The Surface of 2003 EL61 in the Near Infrared". The Astrophysical Journal 655 (2): 1172–1178. arXiv:astro-ph/0601618. Bibcode:2007ApJ...655.1172T. doi:10.1086/509861. 
  46. ^ Mike Brown, K. M. Barksume, G. L. Blake, E. L. Schaller, D. L. Rabinowitz, H. G. Roe and C. A. Trujillo (2007). "Methane and Ethane on the Bright Kuiper Belt Object 2005 FY9". The Astronomical Journal 133 (1): 284–289. Bibcode:2007AJ....133..284B. doi:10.1086/509734. 
  47. ^ J. Licandro, W. M. Grundy, N. Pinilla-Alonso, P. Leisy (2006). "Visible spectroscopy of 2003 UB313: evidence for N2 ice on the surface of the largest TNO" (PDF). Astronomy and Astrophysics 458 (1): L5–L8. arXiv:astro-ph/0608044. Bibcode:2006A&A...458L...5L. doi:10.1051/0004-6361:20066028. 
  48. ^ D. Ragozzine, M. E. Brown, C. A. Trujillo, E. L. Schaller. "Orbits and Masses of the 2003 EL61 Satellite System". AAS DPS conference 2008. Retrieved 2008-10-17. 
  49. ^ Brown, M. E.; Van Dam, M. A.; Bouchez, A. H.; Le Mignant, D.; Campbell, R. D.; Chin, J. C. Y.; Conrad, A.; Hartman, S. K.; Johansson, E. M.; Lafon, R. E.; Rabinowitz, D. L. Rabinowitz; Stomski, P. J., Jr.; Summers, D. M.; Trujillo, C. A.; Wizinowich, P. L. (2006). "Satellites of the Largest Kuiper Belt Objects" (PDF). The Astrophysical Journal 639 (1): L43–L46. arXiv:astro-ph/0510029. Bibcode:2006ApJ...639L..43B. doi:10.1086/501524. Retrieved 2011-10-19.  edit
  50. ^ M. E. Brown, M. A. van Dam, A. H. Bouchez, D. LeMignant, C. A. Trujillo, R. Campbell, J. Chin, Conrad A., S. Hartman, E. Johansson, R. Lafon, D. L. Rabinowitz, P. Stomski, D. Summers, P. L. Wizinowich (2006). "Satellites of the largest Kuiper belt objects". The Astrophysical Journal 639 (1): L43–L46. arXiv:astro-ph/0510029. Bibcode:2006ApJ...639L..43B. doi:10.1086/501524. 
  51. ^ O. Gingerich (2006). "The Path to Defining Planets" (PDF). Harvard-Smithsonian Center for Astrophysics and IAU EC Planet Definition Committee chair. Retrieved 2007-03-13. 
  52. ^ "JPL Small-Body Database Browser: 90482 Orcus (2004 DW)". NASA JPL. 2008-02-10 last obs. Retrieved 2008-07-02.  (unless otherwise cited)
  53. ^ "JPL Small-Body Database Browser: 28978 Ixion (2001 KX76)". NASA JPL. 2007-07-12 last obs. Retrieved 2008-10-04.  (unless otherwise cited)
  54. ^ "JPL Small-Body Database Browser: 307261 (2002 MS4)". 2009-09-19 last obs. Retrieved 2013-12-23.  (unless otherwise cited)
  55. ^ "JPL Small-Body Database Browser: 120347 Salacia". 2010-11-05 last obs. Retrieved 2013-12-23.  (unless otherwise cited)
  56. ^ "JPL Small-Body Database Browser: 20000 Varuna (2000 WR106)". NASA JPL. 2007-11-17 last obs. Retrieved 2008-07-02.  (unless otherwise cited)
  57. ^ "JPL Small-Body Database Browser: (2005 UQ513)". 2008-11-29 last obs. Retrieved 2008-07-31.  (unless otherwise cited)
  58. ^ "NASA JPL Database Browser: 50000 Quaoar". NASA JPL. Retrieved 2008-12-19.  (unless otherwise cited)
  59. ^ "NASA Small Bodies Database Browser: 2007 OR10". NASA JPL. Retrieved 2008-12-20.  (unless otherwise cited)
  60. ^ "JPL Small-Body Database Browser: 229762 (2007 UK126)". 2009-12-20 last obs. Retrieved 2010-05-02.  (unless otherwise cited)
  61. ^ Marc W. Buie (2007-08-13). "Orbit Fit and Astrometric record for 90377". Deep Ecliptic Survey. Retrieved 2006-01-17.  (unless otherwise cited)
  62. ^ Vilenius, E., Kiss, C., Mommert, M. et al. (April 4, 2012). ""TNOs are Cool": A survey of the trans-Neptunian region VI. Herschel/PACS observations and thermal modeling of 19 classical Kuiper belt objects". Retrieved 2012-05-07. 
  63. ^ S. Fornasier, E. Lellouch, T. Müller, P. Santos-Sanz, P. Panuzzo, C. Kiss, T. Lim, M. Mommert, D. Bockelée-Morvan, E. Vilenius, J. Stansberry, G.P. Tozzi, S. Mottola, A. Delsanti, J. Crovisier, R. Duffard, F. Henry, P. Lacerda, A. Barucci, & A. Gicquel (2013). TNOs are Cool: A survey of the trans-Neptunian region. VIII. Combined Herschel PACS and SPIRE observations of 9 bright targets at 70–500 µm.
  64. ^ a b Brown, M.E.; Ragozzine, D.; Stansberry, J.; Fraser, W.C. (2009). "The size, density, and formation of the Orcus-Vanth system in the Kuiper belt". AJ 139 (6): 2700. arXiv:0910.4784. Bibcode:2010AJ....139.2700B. doi:10.1088/0004-6256/139/6/2700. 
  65. ^ a b J.A. Stansberry (2012). "Physical Properties of Trans-Neptunian Binaries (120347) Salacia–Actaea and (42355) Typhon–Echidna". Elsevier. Retrieved 2012-04-27. 
  66. ^ a b Brown, M.E.; Fraser, Wesley (2009). "Quaoar: A Rock in the Kuiper Belt". DPS meeting #41. American Astronomical Society. Bibcode:2009DPS....41.6503F.  (Backup reference)
  67. ^ a b David C. Jewitt and Scott S. Sheppard (2002). "Physical Properties of Trans-Neptunian Object (20000) Varuna". The Astronomical Journal 123 (4): 2110–2120. arXiv:astro-ph/0201082. Bibcode:2002AJ....123.2110J. doi:10.1086/339557.  Retrieved on 2008-12-19.
  68. ^ "Case of Sedna's Missing Moon Solved". Harvard Smithsonian Center for Astrophysics. 2005. Retrieved 2011-07-05. 
  69. ^ Distant EKO The Kuiper Belt Electronic newsletter, March 2007 Retrieved on 2008-11-17
  70. ^ "IAUC 8812: Sats OF 2003 AZ_84, (50000), (55637),, (90482); V1281 Sco; V1280 Sco". International Astronomical Union. Retrieved 2011-07-05. 
  71. ^ (229762) 2007 UK126, Johnston's Archive. Last updated 20 September 2011
  72. ^ Stephen Soter (2006-08-16). "What is a Planet?". The Astronomical Journal 132 (6): 2513–2519. arXiv:astro-ph/0608359. Bibcode:2006AJ....132.2513S. doi:10.1086/508861. 
  73. ^ Lorenzo Iorio (March 2007). "Dynamical determination of the mass of the Kuiper Belt from motions of the inner planets of the Solar system". Monthly Notices of the Royal Astronomical Society 375 (4): 1311–1314. Bibcode:2007MNRAS.tmp...24I. doi:10.1111/j.1365-2966.2006.11384.x. 
  74. ^ a b NASA Saturnian Satellite Fact Sheet NASA Retrieved on 2008-11-17
  75. ^ "NASA Solar System Exploration: Planet Symbols". NASA. Retrieved 2009-01-26. 
  76. ^ James L. Hilton. "When did asteroids become minor planets?" (PDF). U.S. Naval Observatory. Retrieved 2008-10-25. 
  77. ^ "NASA Uranian Satellite Fact Sheet". NASA. Retrieved 2008-11-17. 
  78. ^ P. Kenneth Seidelmann, ed. (1992). Explanatory Supplement to the Astronomical Almanac. University Science Books. p. 384. 
  79. ^ Scott S. Sheppard. "The Jupiter Satellite Page". Carnegie Institution for Science, Department of Terrestrial Magnetism. Retrieved 2008-04-02. 
  80. ^ Dan Bruton. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics & Astronomy (Stephen F. Austin State University). Retrieved 2009-01-20.