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 in particular: 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 known dwarf planet in the asteroid belt, though 10 Hygeia may also be a gravitationally collapsed spheroid and 704 Interamnia likely was so in the past; all three of these bodies appear to have a significant amount of water ice in their composition.[8][9] 4 Vesta, the second-most-massive asteroid and one that is basaltic in composition, appears to have a fully differentiated interior and was therefore in equilibrium at some point in its history, but no longer is today.[10] 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.[11] Thus Ceres, at 950 km in diameter, is the smallest body for which gravitational measurements indicate current hydrostatic equilibrium.[12] Much larger objects, such as Earth's moon, are not near hydrostatic equilibrium today,[13][14][15] though they are primarily composed of silicate rock and iron respectively (in contrast to most dwarf planet candidates, which are ice and rock). Saturn's moons may have 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 900–1000 km in diameter have significantly lower densities (~ 1.0–1.2 g/ml) than larger bodies such as Pluto (1.86 g/ml). Brown had speculated that this was due to their composition, that they were almost entirely icy. However, Grundy et al.[3] 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 prevailing temperatures of the Kuiper Belt, water ice is quite brittle and is thus strong enough to support open interior spaces (interstices) in objects of this size; they thus concluded 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 900–1000 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.[16] Although the IAU had anticipated Tancredi's recommendations; as of 13 September 2019, the IAU has not responded.

Brown's assessment

Artistic comparison of Pluto, Eris, Haumea, Makemake, Gonggong, Quaoar, Sedna, Orcus, Salacia, 2002 MS₄, and Earth along with the Moon.

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,[17] as of 13 September 2019

Mike Brown considers a large number of trans-Neptunian bodies, ranked by estimated size, to be "probably" dwarf planets.[17] 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".[17]

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 Gonggong, Quaoar, 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 about 400–1000 km have oddly low densities, in the range of about 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.[3] propose therefore that mid-size (< 1000 km), low-density (< 1.4 g/ml) 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 about 900–1000 km.[3]

If Grundy et al.[3] are correct, then among known bodies in the outer Solar System only Pluto–Charon, Eris, Haumea, Gonggong, Makemake, Quaoar, Orcus, Sedna, and perhaps Salacia (which was determined to have a higher density of 1.5 g/cm³ a few months after Grundy's assessment)[18] 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 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.[16]	Per Brown[17]	Category
The Moon	3475	3.344	0.136	(measured, not in equilibrium for its current rotation)[19][20]			(moon of Earth)
N I Triton	2707±2	2.06	0.76	(measured, likely in equilibrium)[21]			(moon of Neptune)
134340 Pluto	2376±3	1.854±0.006	0.49 to 0.66				2:3 resonant
136199 Eris	2326±12	2.52±0.07	0.96				SDO
136108 Haumea	≈ 1560	≈ 2.018	0.51±0.02	(naming rules)			cubewano
S VIII Iapetus	1469±6	1.09±0.01	0.05 to 0.5	(measured, not in equilibrium)[22]			(moon of Saturn)
136472 Makemake	1430+38 −22	1.9±0.2	0.81+0.03 −0.05	(naming rules)			cubewano
225088 Gonggong	1230±50	1.74±0.16	0.14		NA		3:10 resonant
P I Charon	1212±1	1.70±0.02	0.2 to 0.5	(measured, likely in equilibrium)[23]			(moon of Pluto)
50000 Quaoar	1121±1.2	2.0±0.5	0.11				cubewano
90377 Sedna	995±80	?	0.32±0.06				detached
1 Ceres	946±2	2.16±0.01	0.09		(measured, close to equilibrium)[24]		asteroid
90482 Orcus	910+50 −40	1.53±0.14	0.23±0.02				2:3 resonant
120347 Salacia	846±21	1.5±0.12	0.04				cubewano
(307261) 2002 MS4	765±47	?	0.05+0.04 −0.02		NA		cubewano
(532037) 2013 FY27	740+90 −85	?	0.17+0.05 −0.03		NA	?	SDO
(208996) 2003 AZ84	727+62 −67	0.87±0.01?	0.10			?	2:3 resonant
S I Mimas	396±1	1.145±0.007	0.962±0.004	(gravitationally rounded, but not in hydrostatic equilibrium for its current rotation)[25]			(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.[26][27]

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.[28] The dwarf planet Ceres is added for comparison. 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.[29]

Designation	Best[lower-alpha 1] diameter km	Measured			per measured	Per Brown[17]			Diameter per assumed albedo		Result per Tancredi[16]	Category
Designation	Best[lower-alpha 1] diameter km	Mass[lower-alpha 2] (10¹⁸ kg)	H [30][31]	Diameter (km)	Geometric albedo[lower-alpha 3] (%)	H	Diameter[lower-alpha 4] (km)	Geometric albedo (%)	Small albedo=100% (km)	Large albedo=4% (km)	Result per Tancredi[16]	Category
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	1560	4006	0.2	1560±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 Gonggong	1230	1750	2.34	1230±50	14	2	1290	19	636	3180		3:10 resonant
50000 Quaoar	1121	1400	2.74	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
174567 Varda	767	266	3.61	767+14 −15	12	3.7	689	13	252	1260	possible	cubewano
(307261) 2002 MS4	765		3.6	765±47	7	4	960	5	253	1266		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
(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
229762 Gǃkúnǁʼhòmdímà	655	136	3.7	655±14	15	3.7	612	17	242	1209		SDO
20000 Varuna	654		3.76	654+154 −102	12	4.1	756	9	235	1176	accepted	cubewano
(455502) 2003 UZ413	650		4.38	650+1 −175	7	4.7	536	8	96	481		2:3 resonant
2014 UZ224	635		3.4	635+65 −72	13	4	688	11	278	1388		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
(303775) 2005 QU182	584		3.8	584+155 −144	13	3.8	415	33	231	1155		cubewano
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
(78799) 2002 XW93	565		5.5	565+71 −73	4	5.4	584	4	106	528		SDO
(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
(543354) 2014 AN55	561		4.1			4.6	561	9	201	1006		SDO
2004 XR190	561		4.3			4.6	561	9	183	917		detached
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
2014 YA50	536		4.6			4.7	536	8	160	799		cubewano
2017 OF69	533		4.6						160	799		2:3 resonant
(145451) 2005 RM43	524		4.4	524+96 −103		4.8	524	8	175	876	possible	SDO
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
(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
(145480) 2005 TB190	507		4.4	507+127 −116	14	4.4	469	15	175	876		detached
(84522) 2002 TC302	504		3.9	504±12	14	4.2	591	12	221	1103		2:5 resonant
(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
(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
(175113) 2004 PF115	468		4.54	468+39 −41	12	4.5	482	12	164	821		2:3 resonant
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
(120132) 2003 FY128	460		4.6	460±21	12	5.1	467	8	160	799		SDO
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
(26181) 1996 GQ21	456		4.9	456+89 −105	6	5.3	468	7	139	696		SDO
(119951) 2002 KX14	455		4.86	455±27	10	4.9	468	10	142	709		cubewano
(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
2013 SF106	443		5.0						133	665		SDO
(82075) 2000 YW134	437		4.74	437+118 −137	13	4.9	513	8	167	837		detached
471143 Dziewanna	433		3.8	433+63 −64	30	3.8	475	25	231	1155		SDO
(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
(182934) 2002 GJ32	416		6.16	416+81 −73	3	6.1	235	12	78	390		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
2012 VB116	404		5.2						121	606		cubewano
(307616) 2003 QW90	401		5	401+63 −48	8	5.4	457	6	133	665		cubewano
(469615) 2004 PT107	400		6.33	400+45 −51	3	6	302	8	72	360		cubewano

The measured diameter, else Brown's estimated diameter, else the diameter calculated from H using an assumed albedo of 9%.
This is the total system mass (including moons), except for Pluto and Ceres.
The geometric albedo $A$ is calculated from the measured absolute magnitude $H$ and measured diameter $D$ via the formula: $A=\left({\frac {1329\times 10^{-H/5}}{D}}\right)^{2}$
Diameters with the text in red indicate that Brown's bot derived them from heuristically expected albedo.

References

Mike Brown. "The Dwarf Planets". Retrieved 20 January 2008.
Stern, Alan (24 August 2012). "The Kuiper Belt at 20: Paradigm Changes in Our Knowledge of the Solar System". Applied Physics Laboratory. 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.
Grundy, W.M.; Noll, K.S.; Buie, M.W.; Benecchi, S.D.; Ragozzine, D.; Roe, H.G. (December 2019). "The mutual orbit, mass, and density of transneptunian binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK₁₂₆)" (PDF). Icarus. 334: 30–38. doi:10.1016/j.icarus.2018.12.037. Archived from the original (PDF) on 7 April 2019.
Bruton, Dan. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics & Astronomy (Stephen F. Austin State University). Archived from the original on 23 March 2010. Retrieved 13 June 2008.
"IAU 2006 General Assembly: Result of the IAU Resolution votes". International Astronomical Union. 24 August 2006. Archived from the original on 3 January 2007. Retrieved 26 January 2008.
"Dwarf Planets". NASA. Archived from the original on 4 July 2012. Retrieved 22 January 2008.
"Plutoid chosen as name for Solar System objects like Pluto" (Press release). 11 June 2008. Archived from the original on 2 July 2011. Retrieved 15 June 2008.
"ESO science paper 1918a" (PDF).
Hanuš, J.; Vernazza, P.; Viikinkoski, M.; Ferrais, M.; Rambaux, N.; Podlewska-Gaca, E.; Drouard, A.; Jorda, L.; Jehin, E.; Carry, B.; Marsset, M.; Marchis, F.; Warner, B.; Behrend, R.; Asenjo, V.; Berger, N.; Bronikowska, M.; Brothers, T.; Charbonnel, S.; Colazo, C.; Coliac, J-F.; Duffard, R.; Jones, A.; Leroy, A.; Marciniak, A.; Melia, R.; Molina, D.; Nadolny, J.; Person, M.; et al. (2020). "arXiv paper 1911.13049". Astronomy & Astrophysics. A65: 633. arXiv:1911.13049. doi:10.1051/0004-6361/201936639.
Savage, Don; Jones, Tammy; Villard, Ray (19 April 1995). "Asteroid or mini-planet? Hubble maps the ancient surface of Vesta". HubbleSite (Press release). News Release STScI-1995-20. Retrieved 17 October 2006.
"Iapetus' peerless equatorial ridge". www.planetary.org. Retrieved 2 April 2018.
"DPS 2015: First reconnaissance of Ceres by Dawn". www.planetary.org. Retrieved 2 April 2018.
Garrick; Bethell; et al. (2014). "The tidal-rotational shape of the Moon and evidence for polar wander". Nature. 512 (7513): 181–184. Bibcode:2014Natur.512..181G. doi:10.1038/nature13639. PMID 25079322.
Balogh, A.; Ksanfomality, Leonid; Steiger, Rudolf von (23 February 2008). Hydrostatic equilibrium of Mercury. ISBN 9780387775395 – via Google Books.
"[no title cited]". doi:10.1002/2015GL065101. Cite journal requires |journal= (help)
Tancredi, G. (2010). "Physical and dynamical characteristics of icy "dwarf planets" (plutoids)". Icy Bodies of the Solar System: Proceedings IAU Symposium No. 263, 2009. 263: 173–185. Bibcode:2010IAUS..263..173T. doi:10.1017/S1743921310001717.
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.
Grundy, W.M.; Noll, K.S.; Roe, H.G.; Buie, M.W.; Porter, S.B.; Parker, A.H.; et al. (December 2019). "Mutual orbit orientations of transneptunian binaries" (PDF). Icarus. 334: 62–78. Bibcode:2019Icar..334...62G. doi:10.1016/j.icarus.2019.03.035. Archived from the original (PDF) on 7 April 2019.
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.
Bursa, M. (October 1984). "Secular Love Numbers and Hydrostatic Equilibrium of Planets". Earth, Moon, and Planets. 31 (2): 135–140. Bibcode:1984EM&P...31..135B. doi:10.1007/BF00055525.
Thomas, P.C. (December 2000). "The Shape of Triton from Limb Profiles". Icarus. 148 (2): 587–588. Bibcode:2000Icar..148..587T. doi:10.1006/icar.2000.6511.
Thomas, P.C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission" (PDF). Icarus. 208 (1): 395–401. Bibcode:2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025.
Kholshevnikovab, K.V.; Borukhaa, M.A.; Eskina, B.B.; Mikryukov, D.V. (23 October 2019). "On the asphericity of the figures of Pluto and Charon". Icarus. 181: 104777. doi:10.1016/j.pss.2019.104777.
Raymond, C.; Castillo-Rogez, J.C.; Park, R.S.; Ermakov, A.; et al. (September 2018). "Dawn Data Reveal Ceres' Complex Crustal Evolution" (PDF). European Planetary Science Congress. 12.
Tajeddine, R.; Rambaux, N.; Lainey, V.; Charnoz, S.; et al. (17 October 2014). "Constraints on Mimas' interior from Cassini ISS libration measurements". Science. 346 (6207): 322–324. Bibcode:2014Sci...346..322T. doi:10.1126/science.1255299. PMID 25324382.
Vernazza, P.; Jorda, L.; Ševeček, P.; Brož, M.; Viikinkoski, M.; Hanuš, J.; et al. (28 October 2019). "A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea" (PDF). Nature Astronomy. 273 (2): 136–141. doi:10.1038/s41550-019-0915-8. hdl:10045/103308. Retrieved 28 October 2019.
Strickland, Ashley; Woodyatt, Amy (28 October 2019). "It's an asteroid! No, it's the new smallest dwarf planet in our solar system". CNN. Retrieved 28 October 2019.
"AstDys (47171) 1999TC36 Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 7 December 2009.
Johnston, Wm. Robert (24 May 2019). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 11 August 2019.
"List Of Trans-Neptunian Objects". Minor Planet Center.
"List Of Centaurs and Scattered-Disk Objects". Minor Planet Center.

External links

NASA JPL Small-Body Database Search Engine
TNOs are cool public database, incl. diameters and albedos measured by Herschel and Spitzer to date, Herschel OT KP "TNOs are Cool: A Survey of the Transneptunian Region"
How many dwarf planets are there in the outer solar system? (updates daily) (Mike Brown)
Details on the dwarf planet size calculations (Mike Brown)
Which are the Dwarfs in the Solar System? Tancredi, G.; Favre, S. Icarus, Volume 195, Issue 2, p. 851–862.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[best_diam-30] The measured diameter, else Brown's estimated diameter, else the diameter calculated from H using an assumed albedo of 9%.

[system_mass-31] This is the total system mass (including moons), except for Pluto and Ceres.

[albedo-34] The geometric albedo $A$ is calculated from the measured absolute magnitude $H$ and measured diameter $D$ via the formula: $A=\left({\frac {1329\times 10^{-H/5}}{D}}\right)^{2}$

[brown_albedo-35] Diameters with the text in red indicate that Brown's bot derived them from heuristically expected albedo.

[Brown-1] Mike Brown. "The Dwarf Planets". Retrieved 20 January 2008.

[Stern2012-2] Stern, Alan (24 August 2012). "The Kuiper Belt at 20: Paradigm Changes in Our Knowledge of the Solar System". Applied Physics Laboratory. 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.

[Grundy2019-3] Grundy, W.M.; Noll, K.S.; Buie, M.W.; Benecchi, S.D.; Ragozzine, D.; Roe, H.G. (December 2019). "The mutual orbit, mass, and density of transneptunian binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK₁₂₆)" (PDF). Icarus. 334: 30–38. doi:10.1016/j.icarus.2018.12.037. Archived from the original (PDF) on 7 April 2019.

[bruton-4] Bruton, Dan. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics & Astronomy (Stephen F. Austin State University). Archived from the original on 23 March 2010. Retrieved 13 June 2008.

[iau2006-5] "IAU 2006 General Assembly: Result of the IAU Resolution votes". International Astronomical Union. 24 August 2006. Archived from the original on 3 January 2007. Retrieved 26 January 2008.

[6] "Dwarf Planets". NASA. Archived from the original on 4 July 2012. Retrieved 22 January 2008.

[iau2008-7] "Plutoid chosen as name for Solar System objects like Pluto" (Press release). 11 June 2008. Archived from the original on 2 July 2011. Retrieved 15 June 2008.

[8] "ESO science paper 1918a" (PDF).

[9] Hanuš, J.; Vernazza, P.; Viikinkoski, M.; Ferrais, M.; Rambaux, N.; Podlewska-Gaca, E.; Drouard, A.; Jorda, L.; Jehin, E.; Carry, B.; Marsset, M.; Marchis, F.; Warner, B.; Behrend, R.; Asenjo, V.; Berger, N.; Bronikowska, M.; Brothers, T.; Charbonnel, S.; Colazo, C.; Coliac, J-F.; Duffard, R.; Jones, A.; Leroy, A.; Marciniak, A.; Melia, R.; Molina, D.; Nadolny, J.; Person, M.; et al. (2020). "arXiv paper 1911.13049". Astronomy & Astrophysics. A65: 633. arXiv:1911.13049. doi:10.1051/0004-6361/201936639.

[Hubble-10] Savage, Don; Jones, Tammy; Villard, Ray (19 April 1995). "Asteroid or mini-planet? Hubble maps the ancient surface of Vesta". HubbleSite (Press release). News Release STScI-1995-20. Retrieved 17 October 2006.

[11] "Iapetus' peerless equatorial ridge". www.planetary.org. Retrieved 2 April 2018.

[12] "DPS 2015: First reconnaissance of Ceres by Dawn". www.planetary.org. Retrieved 2 April 2018.

[13] Garrick; Bethell; et al. (2014). "The tidal-rotational shape of the Moon and evidence for polar wander". Nature. 512 (7513): 181–184. Bibcode:2014Natur.512..181G. doi:10.1038/nature13639. PMID 25079322.

[14] Balogh, A.; Ksanfomality, Leonid; Steiger, Rudolf von (23 February 2008). Hydrostatic equilibrium of Mercury. ISBN 9780387775395 – via Google Books.

[15] "[no title cited]". doi:10.1002/2015GL065101. Cite journal requires |journal= (help)

[tancredi-2010-16] Tancredi, G. (2010). "Physical and dynamical characteristics of icy "dwarf planets" (plutoids)". Icy Bodies of the Solar System: Proceedings IAU Symposium No. 263, 2009. 263: 173–185. Bibcode:2010IAUS..263..173T. doi:10.1017/S1743921310001717.

[brown-list-17] 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.

[Grundy2019-2-18] Grundy, W.M.; Noll, K.S.; Roe, H.G.; Buie, M.W.; Porter, S.B.; Parker, A.H.; et al. (December 2019). "Mutual orbit orientations of transneptunian binaries" (PDF). Icarus. 334: 62–78. Bibcode:2019Icar..334...62G. doi:10.1016/j.icarus.2019.03.035. Archived from the original (PDF) on 7 April 2019.

[TheMoon-19] 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.

[MoonLove-20] Bursa, M. (October 1984). "Secular Love Numbers and Hydrostatic Equilibrium of Planets". Earth, Moon, and Planets. 31 (2): 135–140. Bibcode:1984EM&P...31..135B. doi:10.1007/BF00055525.

[21] Thomas, P.C. (December 2000). "The Shape of Triton from Limb Profiles". Icarus. 148 (2): 587–588. Bibcode:2000Icar..148..587T. doi:10.1006/icar.2000.6511.

[22] Thomas, P.C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission" (PDF). Icarus. 208 (1): 395–401. Bibcode:2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025.

[23] Kholshevnikovab, K.V.; Borukhaa, M.A.; Eskina, B.B.; Mikryukov, D.V. (23 October 2019). "On the asphericity of the figures of Pluto and Charon". Icarus. 181: 104777. doi:10.1016/j.pss.2019.104777.

[24] Raymond, C.; Castillo-Rogez, J.C.; Park, R.S.; Ermakov, A.; et al. (September 2018). "Dawn Data Reveal Ceres' Complex Crustal Evolution" (PDF). European Planetary Science Congress. 12.

[Mimas-25] Tajeddine, R.; Rambaux, N.; Lainey, V.; Charnoz, S.; et al. (17 October 2014). "Constraints on Mimas' interior from Cassini ISS libration measurements". Science. 346 (6207): 322–324. Bibcode:2014Sci...346..322T. doi:10.1126/science.1255299. PMID 25324382.

[26] Vernazza, P.; Jorda, L.; Ševeček, P.; Brož, M.; Viikinkoski, M.; Hanuš, J.; et al. (28 October 2019). "A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea" (PDF). Nature Astronomy. 273 (2): 136–141. doi:10.1038/s41550-019-0915-8. hdl:10045/103308. Retrieved 28 October 2019.

[27] Strickland, Ashley; Woodyatt, Amy (28 October 2019). "It's an asteroid! No, it's the new smallest dwarf planet in our solar system". CNN. Retrieved 28 October 2019.

[AstDys-TC36-28] "AstDys (47171) 1999TC36 Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 7 December 2009.

[johnstonsarchive-TNO-list-29] Johnston, Wm. Robert (24 May 2019). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 11 August 2019.

[mpc-tno-32] "List Of Trans-Neptunian Objects". Minor Planet Center.

[mpc-sdo-33] "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center.

Trans-Neptunian objects
TNO classes	Cubewanos Scattered-disc objects Detached objects Resonant objects Neptune trojans Plutinos Twotinos TNO moons
Dwarf planets (moons)	Pluto Charon Styx Nix Kerberos Hydra Haumea Namaka Hiʻiaka Makemake S/2015 (136472) 1 Eris Dysnomia
Sednoids	90377 Sedna 2012 VP113 541132 Leleākūhonua