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List of possible dwarf planets

The number of dwarf planets in the Solar System is unknown. Estimates have run as high as 200 in the Kuiper belt[1] and over 10,000 in the region beyond.[2] However, consideration of the surprisingly low densities of many dwarf-planet candidates suggests that the numbers may be much lower (e.g. at most 10 among bodies known so far).[3] The International Astronomical Union (IAU) notes five: Ceres in the inner Solar System and four in the trans-Neptunian region: Pluto, Eris, Haumea, and Makemake, the last two of which were accepted as dwarf planets for naming purposes.

IAU naming procedures

In 2008, the IAU modified its naming procedures such that objects considered most likely to be dwarf planets receive differing treatment than others. Objects that have an absolute magnitude (H) less than +1, and hence a minimum diameter of 838 kilometres (521 mi) if the albedo is below 100%,[4] are overseen by two naming committees, one for minor planets and one for planets. Once named, the objects are declared to be dwarf planets. Makemake and Haumea are the only objects to have proceeded through the naming process as presumed dwarf planets; currently there are no other bodies that meet this criterion. All other bodies are named by the minor-planet naming committee alone, and the IAU has not stated how or if they will be accepted as dwarf planets.

Limiting values

Calculation of the diameter of Ixion depends on the albedo (the fraction of light that it reflects), which is currently unknown.

Beside directly orbiting the Sun, the qualifying feature of a dwarf planet is that it have "sufficient mass for its self-gravity to overcome rigid-body forces so that it assumes a hydrostatic equilibrium (nearly round) shape".[5][6][7] Current observations are generally insufficient for a direct determination as to whether a body meets this definition. Often the only clues for trans-Neptunian objects is a crude estimate of their diameters and albedos. Icy satellites as large as 1500 km in diameter have proven to not be in equilibrium, whereas dark objects in the outer solar system often have low densities that imply they are not even solid bodies, much less gravitationally controlled dwarf planets.

Ceres is currently the only recognized dwarf planet in the asteroid belt, though 10 Hygeia may also be a gravitationally collapsed spheroid; both of these objects appear to have a significant amount of water ice in their composition.[8] 4 Vesta, the second-most-massive asteroid, appears to have a fully differentiated interior and was therefore in equilibrium at some point in its history, but it is not today.[9] The third-most massive object, 2 Pallas, has a somewhat irregular surface and is thought to have only a partially differentiated interior. Michael Brown has estimated that, because rocky objects such as Vesta and Pallas are more rigid than icy objects, rocky objects below 900 kilometres (560 mi) in diameter may not be in hydrostatic equilibrium and thus not dwarf planets.[1]

Based on a comparison with the icy moons that have been visited by spacecraft, such as Mimas (round at 400 km in diameter) and Proteus (irregular at 410–440 km in diameter), Brown estimated that an icy body relaxes into hydrostatic equilibrium at a diameter somewhere between 200 and 400 km.[1] However, after Brown and Tancredi made their calculations, better determination of their shapes showed that Mimas and the other mid-sized ellipsoidal moons of Saturn up to at least Iapetus (which is of the approximate size of Haumea and Makemake) are no longer in hydrostatic equilibrium. They have equilibrium shapes that froze in place some time ago, and do not match the shapes that equilibrium bodies would have at their current rotation rates.[10] Thus Ceres, at 950 km in diameter, is the smallest body for which gravitational measurements indicate current hydrostatic equilibrium,[11] and Earth's moon, at 3,474 km, is the largest body known to not be in equilibrium. The Moon is entirely rocky, unlike Ceres, Saturn's moons and almost all of the dwarf planet candidates, which are ice and rock. Saturn's moons may have also been subject to a thermal history that would have produced equilibrium-like shapes in bodies too small for gravity alone to do so. Thus, at present it is unknown whether any trans-Neptunian objects smaller than Pluto and Eris are in hydrostatic equilibrium.[3] The IAU has not addressed this issue since these findings.

The majority of mid-sized TNOs up to about 900 or 1000 km in diameter have significantly lower (1-1.2 gm/ml) densities than larger bodies such as Pluto (1.8 gm/ml). Brown had speculated that this was due to their composition, that they were almost entirely icy. However, Grundy et al. point out that there is no known mechanism or evolutionary pathway for mid-sized bodies to be icy while both larger and smaller objects are partially rocky. They demonstrated that at the temperatures of the Kuiper Belt, water ice is strong enough to support open interior spaces (interstices) in objects of this size, and conclude that they have low densities for the same reason that smaller objects do—because they have not compacted under self-gravity into fully solid objects, and thus the typical object smaller than 900 or 1000 km in diameter is (pending some other formative mechanism) unlikely to be a dwarf planet.

Tancredi's assessment

In 2010, Gonzalo Tancredi presented a report to the IAU evaluating a list of 46 candidates for dwarf planet status based on light-curve-amplitude analysis and the assumption that the object was more than 450 kilometres (280 mi) in diameter. Some diameters are measured, some are best-fit estimates, and others use an assumed albedo of 0.10. Of these, he identified 15 as dwarf planets by his criteria (including the 4 accepted by the IAU), with another 9 being considered possible. To be cautious, he advised the IAU to "officially" accept as dwarf planets the top three not yet accepted: Sedna, Orcus, and Quaoar.[12] Although the IAU had anticipated Tancredi's recommendations, as of 2013, they have not responded.

Brown's assessment

Brown's categories Min. Number of objects
nearly certainly >900 km 10
highly likely 600–900 km 27
likely 500–600 km 68
probably 400–500 km 130
possibly 200–400 km 741
Source: Mike Brown,[13] as of September 13, 2019
EarthMoonCharonCharonNixNixKerberosStyxHydraHydraPlutoPlutoDysnomiaDysnomiaErisErisNamakaNamakaHi'iakaHi'iakaHaumeaHaumeaMakemakeMakemakeMK2MK22007 OR102007 OR10S/2010 (225088) 1S/2010 (225088) 1WeywotWeywotQuaoarQuaoarSednaSedna2002 MS42002 MS4VanthVanthOrcusOrcusActaeaActaeaSalaciaSalaciaFile:EightTNOs.png
Artistic comparison of Pluto, Eris, Haumea, Makemake, 2007 OR10, Quaoar, Sedna, 2002 MS4, Orcus, Salacia, and Earth along with the Moon.

Mike Brown considers a large number of trans-Neptunian bodies, ranked by estimated size, to be "probably" dwarf planets.[13] He did not consider asteroids, stating "In the asteroid belt Ceres, with a diameter of 900 km, is the only object large enough to be round".[13]

The terms for varying degrees of likelihood he split these into:

  • Near certainty: diameter estimated/measured to be over 900 kilometres (560 mi). Sufficient confidence to say these must be in hydrostatic equilibrium, even if predominantly rocky.
  • Highly likely: diameter estimated/measured to be over 600 kilometres (370 mi). The size would have to be "grossly in error" or they would have to be primarily rocky to not be dwarf planets.
  • Likely: diameter estimated/measured to be over 500 kilometres (310 mi). Uncertainties in measurement mean that some of these will be significantly smaller and thus doubtful.
  • Probably: diameter estimated/measured to be over 400 kilometres (250 mi). Expected to be dwarf planets, if they are icy, and that figure is correct.
  • Possibly: diameter estimated/measured to be over 200 kilometres (120 mi). Icy moons transition from a round to irregular shape in the 200–400 km range, suggesting that the same figure holds true for KBOs. Thus, some of these objects could be dwarf planets.
  • Probably not: diameter estimated/measured to be under 200 km. No icy moon under 200 km is round, suggesting that the same is true for KBOs. The estimated size of these objects would have to be in error for them to be dwarf planets.

Beside the five accepted by the IAU, the 'nearly certain' category includes 2007 OR10, Quaoar, 90377 Sedna, Orcus, 2002 MS4 and Salacia.

Grundy et al's assessment

Grundy et al. propose that dark, low-density TNOs in the size range of approximately 400–1000 km are transitional between smaller, porous (and thus low-density) bodies and larger, denser, brighter and geologically differentiated planetary bodies (such as dwarf planets). Bodies in this size range should have begun to collapse the interstitial spaces left over from their formation, but not fully, leaving some residual porosity.[3]

Many TNOs in the size range of 400–1000 km have oddly low densities, in the range of 1.0–1.2 g/cm3, that are substantially less than dwarf planets such as Pluto, Eris and Ceres, which have densities closer to 2. Brown has suggested that large low-density bodies must be composed almost entirely of water ice, since he presumed that bodies of this size would necessarily be solid. However, this leaves unexplained why TNOs both larger than 1000 km and smaller than 400 km, and indeed comets, are composed of a substantial fraction of rock, leaving only this size range to be primarily icy. Experiments with water ice at the relevant pressures and temperatures suggest that substantial porosity could remain in this size range, and it is possible that adding rock to the mix would further increase resistance to collapsing into a solid body. Bodies with internal porosity remaining from their formation could be at best only partially differentiated, in their deep interiors. (If a body had begun to collapse into a solid body, there should be evidence in the form of fault systems from when its surface contracted.) The higher albedos of larger bodies is also evidence of full differentiation, as such bodies were presumably resurfaced with ice from their interiors. Grundy et al. propose therefore that mid-size, low-density and low-albedo (< ≈0.2) bodies such as Salacia, Varda, Gǃkúnǁʼhòmdímà and (55637) 2002 UX25 are not differentiated planetary bodies like Orcus, Quaoar and Charon. The boundary between the two populations would appear to be in the range of 900–1000 km.[3]

If Grundy et al. are correct, then among known bodies in the outer Solar System only Pluto–Charon, Eris, Haumea, 2007 OR10, Makemake, Quaoar, Orcus, Sedna, and perhaps Salacia (which was determined to have a higher density of 1.5 gm/cm^3 a few months after Grundy's assessment[14]) are likely to have achieved hydrostatic equilibrium at some point in their histories, and thus to possibly still be dwarf planets at present.

Likeliest dwarf planets

The assessments of the IAU, Tancredi et al., Brown and Grundy et al. for the dozen largest potential dwarf planets are as follows. For the IAU, the acceptance criteria were for naming purposes. Several of these objects had not yet been discovered when Tancredi et al. did their analysis. Brown's sole criterion is diameter; he accepts a great many more as highly likely to be dwarf planets (see below). Grundy et al. did not determine which bodies were dwarf planets, but rather which could not be. A red No marks objects too dark or not dense enough to be solid bodies, a question mark the smaller bodies consistent with being differentiated (the question of current equilibrium was not addressed).

Iapetus, Earth's Moon, and Mimas are included for comparison, as none of these objects are in equilibrium today. Triton and Charon (which formed as TNO's and are likely in equilibrium) are also added for comparison.

Designation Measured mean
diameter (km)
Density
(g/cm³)
Albedo Per IAU Per Tancredi
et al.[12]
Per Brown[13] Per Grundy
et al.[3]
Category
No The Moon 3475 3.344 0.136 (measured, not in equilibrium for its current rotation)[15][16] (moon of Earth)
N I Triton 2707±2 2.06 0.76 (measured, likely in equilibrium)[17] (moon of Neptune)
134340 Pluto 2376±3 1.854±0.006 0.49 to 0.66 Yes Yes Yes 2:3 resonant
136199 Eris 2326±12 2.52±0.07 0.96 Yes Yes Yes SDO
136108 Haumea 1596±12 1.885±0.080 0.51±0.02 Yes
(naming rules)
Yes Yes cubewano
No S VIII Iapetus 1469±6 1.09±0.01 0.05 to 0.5 (measured, not in equilibrium)[18] (moon of Saturn)
136472 Makemake 1430+38
−22
1.9±0.2 0.81+0.03
−0.05
Yes
(naming rules)
Yes Yes cubewano
(225088) 2007 OR10 1230±50 1.74±0.16 0.14 NA Yes Maybe 3:10 resonant
P I Charon 1212±1 1.70±0.02 0.2 to 0.5 (measured, likely in equilibrium)[19] (moon of Pluto)
50000 Quaoar 1121±1.2 2.0±0.5 0.11 Yes Yes Maybe cubewano
90377 Sedna 995±80 ? 0.32±0.06 Yes Yes Maybe detached
Yes 1 Ceres 946±2 2.16±0.01 0.09 Yes (measured, close to equilibrium)[20] asteroid
90482 Orcus 910+50
−40
1.53±0.14 0.23±0.02 Yes Yes Maybe 2:3 resonant
120347 Salacia 846±21 1.5±0.12 0.04 Maybe Yes No cubewano
(307261) 2002 MS4 765±47 ? 0.05+0.04
−0.02
NA Yes No cubewano
(532037) 2013 FY27 740+90
−85
? 0.17+0.05
−0.03
NA Yes? No SDO
(208996) 2003 AZ84 727+62
−67
0.87±0.01? 0.10 Yes Yes? No 2:3 resonant
No S I Mimas 396±1 1.145±0.007 0.962±0.004 (gravitationally rounded, but not in hydrostatic equilibrium for its current rotation)[21] (moon of Saturn)

Observations in 2019 showed that the asteroid 10 Hygiea was close to spherical, so it is possible that it may be in hydrostatic equilibrium (and thus a dwarf planet) as well.[22][23]

Largest candidates

The following trans-Neptunian objects have estimated diameters at least 400 kilometres (250 mi) and so are considered "probable" dwarf planets by Brown's assessment. Not all bodies estimated to be this size are included. The list is complicated by bodies such as 47171 Lempo that were at first assumed to be large single objects but later discovered to be binary or triple systems of smaller bodies.[24] The dwarf planet Ceres is added for comparison.

The IAU-recognised dwarf planets have bold names. Explanations and sources for the measured masses and diameters can be found in the corresponding articles linked in column "Designation" of the table.

The Best diameter column uses a measured diameter if one exists, otherwise it uses Brown's assumed-albedo diameter. If Brown does not list the body, the size is calculated from an assumed-albedo of 9% per Johnston.[25]

Designation Best[a]
diameter
km
Measured per
measured
Per Brown[13] Diameter
per assumed albedo
Result
per Tancredi[12]
Category
Mass[b]
(1018 kg)
H

[26][27]

Diameter
(km)
Geometric
albedo[c]
(%)
H
Diameter[d]
(km)
Geometric
albedo

(%)
Small
albedo=100%
(km)
Large
albedo=4%
(km)
134340 Pluto 2376 13030 −0.76 2376±3.2 63 −0.7 2329 64 1886 9430 accepted (measured) 2:3 resonant
136199 Eris 2326 16600 −1.1 2326±12 90 −1.1 2330 99 2206 11028 accepted (measured) SDO
136108 Haumea 1596 4006 0.2 1596±12 58 0.4 1252 80 1212 6060 accepted cubewano
136472 Makemake 1430 3100 −0.2 1430±14 104 0.1 1426 81 1457 7286 accepted cubewano
(225088) 2007 OR10 1230 1750 2.34 1230±50 14 2 1290 19 636 3180 3:10 resonant
50000 Quaoar 1121 1400 2.82 1121±1.2 11 2.7 1092 13 363 1813 accepted (and recommended) cubewano
90377 Sedna 995 1.83 995±80 33 1.8 1041 32 572 2861 accepted (and recommended) detached
1 Ceres 939 939 3.36 939±2 9 283 1414 asteroid belt
90482 Orcus 917 641 2.31 917±25 25 2.3 983 23 459 2293 accepted (and recommended) 2:3 resonant
120347 Salacia 846 492 4.25 846±21 5 4.2 921 4 188 939 possible cubewano
(55565) 2002 AW197 768 3.3 768+39
−38
14 3.8 754 12 291 1454 accepted cubewano
(307261) 2002 MS4 765 3.6 765±47 7 4 960 5 253 1266 cubewano
174567 Varda 757 266 3.61 757+14
−15
12 3.7 689 13 252 1260 possible cubewano
(532037) 2013 FY27 740 3.15 740+90
−85
18 3.5 721 14 312 1558 SDO
(208996) 2003 AZ84 732 3.74 732±26 11 3.7 747 11 237 1187 accepted 2:3 resonant
(90568) 2004 GV9 680 4.25 680±34 8 4.2 703 8 188 939 accepted cubewano
(145452) 2005 RN43 679 3.89 679+55
−73
11 3.9 697 11 222 1108 possible cubewano
20000 Varuna 668 3.76 668+154
−86
12 4.1 756 9 235 1176 accepted cubewano
(55637) 2002 UX25 665 125 3.87 665±29 11 3.9 704 11 224 1118 cubewano
2018 VG18 656 3.6 3.6 656 12 253 1266 SDO
2014 UZ224 635 3.4 635+65
−72
19 4 688 11 278 1388 SDO
229762 Gǃkúnǁʼhòmdímà 632 136 3.7 632+34
−34
15 3.7 612 17 242 1209 SDO
(523794) 2015 RR245 626 3.8 4.2 626 10 231 1155 SDO
(523692) 2014 EZ51 626 3.8 4.2 626 10 231 1155 detached
28978 Ixion 617 3.83 617+19
−20
14 3.8 674 12 228 1139 accepted 2:3 resonant
2010 RF43 615 3.9 4.2 615 10 221 1103 SDO
19521 Chaos 600 4.8 600+140
−130
6 5 612 5 146 729 cubewano
2015 KH162 587 4.1 4.4 587 10 201 1006 detached
(84522) 2002 TC302 584 3.9 584+106
−88
14 4.2 591 12 221 1103 2:5 resonant
(78799) 2002 XW93 584 5.5 5.4 584 4 106 528 SDO
2010 JO179 574 4 4.5 574 9 211 1053 SDO
2010 KZ39 574 4 4.5 574 9 211 1053 detached
(523759) 2014 WK509 574 4.4 4.5 574 9 175 876 detached
2012 VP113 574 4 4.5 574 9 211 1053 detached
(523671) 2013 FZ27 561 4.4 4.6 561 9 175 876 1:2 resonant
(523639) 2010 RE64 561 4.4 4.6 561 9 175 876 SDO
2014 AN55 561 4.1 4.6 561 9 201 1006 SDO
2004 XR190 561 4.3 4.6 561 9 183 917 detached
(42301) 2001 UR163 561 4.1 4.6 561 9 201 1006 possible SDO
2002 XV93 549 5.42 549+22
−23
4 5.4 564 4 110 548 2:3 resonant
2010 FX86 549 4.7 4.6 549 9 153 763 cubewano
(528381) 2008 ST291 549 4.4 4.6 549 9 175 876 detached
(84922) 2003 VS2 548 4.1 548+30
−45
15 4.1 537 15 201 1006 not accepted 2:3 resonant
2006 QH181 536 4.3 4.7 536 8 183 917 SDO
(455502) 2003 UZ413 536 4.3 4.7 536 8 183 917 2:3 resonant
2014 YA50 536 4.6 4.7 536 8 160 799 cubewano
2017 OF69 533 4.6 160 799 2:3 resonant
2015 BP519 524 4.5 4.8 524 8 167 837 SDO
(482824) 2013 XC26 524 4.4 4.8 524 8 175 876 cubewano
(470443) 2007 XV50 524 4.4 4.8 524 8 175 876 cubewano
(145451) 2005 RM43 524 4.4 4.8 524 8 175 876 possible SDO
(82075) 2000 YW134 513 4.5 4.9 513 8 167 837 detached
(470308) 2007 JH43 513 4.5 4.9 513 8 167 837 2:3 resonant
(278361) 2007 JJ43 513 4.5 4.9 513 8 167 837 cubewano
(523681) 2014 BV64 513 4.7 4.9 513 8 153 763 cubewano
2014 HA200 513 4.7 4.9 513 8 153 763 SDO
2014 FC72 513 4.7 4.9 513 8 153 763 detached
2015 BZ518 513 4.7 4.9 513 8 153 763 cubewano
2014 WP509 513 4.5 4.9 513 8 167 837 cubewano
(120348) 2004 TY364 512 4.52 512+37
−40
10 4.7 536 8 166 829 not accepted 2:3 resonant
(472271) 2010 TQ182 509 4.7 153 763 cubewano
(523645) 2010 VK201 501 5 5 501 7 133 665 cubewano
2013 AT183 501 4.6 5 501 7 160 799 SDO
(523742) 2014 TZ85 501 4.8 5 501 7 146 729 4:7 resonant
2014 FC69 501 4.6 5 501 7 160 799 detached
(499514) 2010 OO127 501 4.6 5 501 7 160 799 cubewano
(202421) 2005 UQ513 498 3.6 498+63
−75
26 4 643 11 253 1266 cubewano
(315530) 2008 AP129 490 4.7 5.1 490 7 153 763 cubewano
(470599) 2008 OG19 490 4.7 5.1 490 7 153 763 SDO
(523635) 2010 DN93 490 4.8 5.1 490 7 146 729 detached
2003 QX113 490 5.1 5.1 490 7 127 635 SDO
2003 UA414 490 5 5.1 490 7 133 665 SDO
(119979) 2002 WC19 490 4.7 5.1 490 7 153 763 1:2 resonant
(472271) 2014 UM33 490 4.7 5.1 490 7 153 763 cubewano
(523693) 2014 FT71 490 5 5.1 490 7 133 665 4:7 resonant
2014 HZ199 479 5 5.2 479 7 133 665 cubewano
2014 BZ57 479 5 5.2 479 7 133 665 cubewano
(523752) 2014 VU37 479 5.1 5.2 479 7 127 635 cubewano
(495603) 2015 AM281 479 4.8 5.2 479 7 146 729 detached
(48639) 1995 TL8 479 4.8 5.2 479 7 146 729 SDO
(307982) 2004 PG115 479 4.8 5.2 479 7 146 729 SDO
471143 Dziewanna 470 3.8 470+35
−10
24 3.8 475 25 231 1155 SDO
(26181) 1996 GQ21 468 4.9 5.3 468 7 139 696 SDO
2015 AJ281 468 5 5.3 468 7 133 665 4:7 resonant
(523757) 2014 WH509 468 5.2 5.3 468 7 121 606 cubewano
2014 JP80 468 5 5.3 468 7 133 665 2:3 resonant
2014 JR80 468 5.1 5.3 468 7 127 635 2:3 resonant
(523750) 2014 US224 468 5 5.3 468 7 133 665 cubewano
2013 FS28 468 4.9 5.3 468 7 139 696 SDO
2010 RF188 468 5.2 5.3 468 7 121 606 SDO
2011 WJ157 468 5 5.3 468 7 133 665 SDO
(145480) 2005 TB190 464 4.4 464±62 14 4.4 469 15 175 876 detached
(26375) 1999 DE9 461 4.8 461±45 10 5.2 474 7 146 729 possible 2:5 resonant
(120132) 2003 FY128 460 4.6 460±21 12 5.1 467 8 160 799 SDO
(307616) 2003 QW90 457 5 5.4 457 6 133 665 cubewano
(469306) 1999 CD158 457 5 5.4 457 6 133 665 4:7 resonant
(308379) 2005 RS43 457 5 5.4 457 6 133 665 1:2 resonant
2010 ER65 457 5.2 5.4 457 6 121 606 detached
(445473) 2010 VZ98 457 4.8 5.4 457 6 146 729 SDO
2010 RF64 457 5.7 5.4 457 6 96 481 cubewano
(523640) 2010 RO64 457 5.2 5.4 457 6 121 606 cubewano
2010 TJ 457 5.7 5.4 457 6 96 481 SDO
2014 OJ394 457 5.1 5.4 457 6 127 635 detached
2014 QW441 457 5.2 5.4 457 6 121 606 cubewano
2014 AM55 457 5.2 5.4 457 6 121 606 cubewano
(523772) 2014 XR40 457 5.2 5.4 457 6 121 606 cubewano
(523653) 2011 OA60 457 5.1 5.4 457 6 127 635 cubewano
2003 QX111 453 7.1 6.8 453 2 51 253 2:3 resonant
(84719) 2002 VR128 449 5.58 449+42
−43
5 5.6 459 5 102 509 2:3 resonant
(471137) 2010 ET65 447 5.1 5.5 447 6 127 635 SDO
(471165) 2010 HE79 447 5.1 5.5 447 6 127 635 2:3 resonant
2010 EL139 447 5.6 5.5 447 6 101 504 2:3 resonant
(523773) 2014 XS40 447 5.4 5.5 447 6 111 553 cubewano
2014 XY40 447 5.1 5.5 447 6 127 635 cubewano
2015 AH281 447 5.1 5.5 447 6 127 635 cubewano
2014 CO23 447 5.3 5.5 447 6 116 579 cubewano
(523690) 2014 DN143 447 5.3 5.5 447 6 116 579 cubewano
(523738) 2014 SH349 447 5.4 5.5 447 6 111 553 cubewano
2014 FY71 447 5.4 5.5 447 6 111 553 4:7 resonant
(471288) 2011 GM27 447 5.1 5.5 447 6 127 635 cubewano
(532093) 2013 HV156 447 5.2 5.5 447 6 121 606 1:2 resonant
(119951) 2002 KX14 445 4.86 445±27 10 4.9 468 10 142 709 cubewano
(471165) 2002 JR146 423 5.1 127 635 2:3 resonant
(444030) 2004 NT33 423 4.8 423+87
−80
12 5.1 490 7 146 729 4:7 resonant
(303775) 2005 QU182 416 3.8 416±73 31 3.8 415 33 231 1155 SDO
(469372) 2001 QF298 408 5.43 408+40
−45
7 5.4 421 7 109 545 2:3 resonant
38628 Huya 406 5.04 406±16 10 5 466 8 130 652 accepted 2:3 resonant
(175113) 2004 PF115 406 4.54 406+98
−75
16 4.5 482 12 164 821 2:3 resonant
2012 VB116 404 5.2 121 606 cubewano
  1. ^ The measured diameter, else Brown's estimated diameter, else the diameter calculated from H using an assumed albedo of 9%.
  2. ^ This is the total system mass (including moons), except for Pluto and Ceres.
  3. ^ The geometric albedo is calculated from the measured absolute magnitude and measured diameter via the formula:
  4. ^ Diameters with the text in red indicate that Brown's bot derived them from heuristically expected albedo.

See also

References

  1. ^ a b c Mike Brown. "The Dwarf Planets". Retrieved 2008-01-20.
  2. ^ "Today we know of more than a dozen dwarf planets in the solar system [and] it is estimated that the ultimate number of dwarf planets we will discover in the Kuiper Belt and beyond may well exceed 10,000".The PI's Perspective
  3. ^ a b c d e W.M. Grundy, K.S. Noll, M.W. Buie, S.D. Benecchi, D. Ragozzine & H.G. Roe, 'The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK126)', Icarus (forthcoming, available online 30 March 2019) DOI: 10.1016/j.icarus.2018.12.037,
  4. ^ Dan Bruton. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics & Astronomy (Stephen F. Austin State University). Archived from the original on 2010-03-23. Retrieved 2008-06-13.
  5. ^ "IAU 2006 General Assembly: Result of the IAU Resolution votes". International Astronomical Union. 2006. Archived from the original on 2007-01-03. Retrieved 2008-01-26.
  6. ^ "Dwarf Planets". NASA. Retrieved 2008-01-22.
  7. ^ "Plutoid chosen as name for Solar System objects like Pluto" (Press release).
  8. ^ [www.eso.org]
  9. ^ Savage, Don; Jones, Tammy; Villard, Ray (1995-04-19). "Asteroid or Mini-Planet? Hubble Maps the Ancient Surface of Vesta". Hubble Site News Release STScI-1995-20. Retrieved 2006-10-17.
  10. ^ "Iapetus' peerless equatorial ridge". www.planetary.org. Retrieved 2 April 2018.
  11. ^ "DPS 2015: First reconnaissance of Ceres by Dawn". www.planetary.org. Retrieved 2 April 2018.
  12. ^ a b c Tancredi, G. (2010). "Physical and dynamical characteristics of icy "dwarf planets" (plutoids)". Icy Bodies of the Solar System: Proceedings IAU Symposium No. 263, 2009.
  13. ^ a b c d e Michael E. Brown (13 September 2019). "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Archived from the original on 13 October 2019. Retrieved 24 November 2019.
  14. ^ [www2.lowell.edu]
  15. ^ Matsuyama, Isamu (January 2013). "Fossil figure contribution to the lunar figure". Icarus. 222 (1): 411–414. Bibcode:2013Icar..222..411M. doi:10.1016/j.icarus.2012.10.025.
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External links