List of natural satellites
List
This is a list of the recognized moons of the planets and of the five recognised dwarf planets of the Solar System, ordered by their official Roman numeral designations.

List of natural satellites

Section Title: List
Table Section Text: This is a list of the recognized moons of the planets and of the five recognised dwarf planets of the Solar System, ordered by their official Roman numeral designations.

Image	Numeral	Name	Mean radius (km)	Semi-major axis (km)	Sidereal period (d) (r = retrograde)	Discovery year	Discovered by	Notes	Ref(s)	Planet

-	I	Moon	1737.10	384,399	27.321582	Prehistoric	—	Synchronous rotation	Earth

-	I	Phobos	11.1 ± 0.15	9,380	0.319	1877	Hall	Mars

-	II	Deimos	6.2 ± 0.18	23,460	1.262	1877	Hall	Mars

I	Io	1818.1 ± 0.1	421,800	1.769	1610	Galileo	Main-group moon (Galilean)	Jupiter

-	II	Europa	1560.7 ± 0.7	671,100	3.551	1610	Galileo	Main-group moon (Galilean)	Jupiter

-	III	Ganymede	2634.1 ± 0.3	1,070,400	7.155	1610	Galileo	Main-group moon (Galilean)	Jupiter

-	IV	Callisto	2408.4 ± 0.3	1,882,700	16.69	1610	Galileo	Main-group moon (Galilean)	Jupiter

-	V	Amalthea	83.5 ± 2	181,400	0.498	1892	Barnard	Inner moon (Amalthea)	Jupiter

-	VI	Himalia	67 ± 10	11,461,000	250.56	1904	Perrine	Prograde irregular (Himalia)	Jupiter

-	VII	Elara	43	11,741,000	259.64	1905	Perrine	Prograde irregular (Himalia)	Jupiter

-	VIII	Pasiphae	30	23,624,000	743.63 (r)	1908	Melotte	Retrograde irregular (Pasiphae)	Jupiter

-	IX	Sinope	19	23,939,000	758.90 (r)	1914	Nicholson	Retrograde irregular (Pasiphae)	Jupiter

-	X	Lysithea	18	11,717,000	259.20	1938	Nicholson	Prograde irregular (Himalia)	Jupiter

-	XI	Carme	23	23,404,000	734.17 (r)	1938	Nicholson	Retrograde irregular (Carme)	Jupiter

-	XII	Ananke	14	21,276,000	629.77 (r)	1951	Nicholson	Retrograde irregular (Ananke)	Jupiter

XIII	Leda	10	11,165,000	240.92	1974	Kowal	Prograde irregular (Himalia)	Jupiter

-	XIV	Thebe	49.3 ± 2.0	221,900	0.675	1979	Synnott (Voyager 1)	Inner moon (Amalthea)	Jupiter

-	XV	Adrastea	8.2 ± 2.0	129,000	0.298	1979	Jewitt, Danielson (Voyager 1)	Inner moon (Amalthea)	Jupiter

-	XVI	Metis	21.5 ± 2.0	128,000	0.295	1979	Synnott (Voyager 1)	Inner moon (Amalthea)	Jupiter

-	XVII	Callirrhoe	4.3	24,103,000	758.77 (r)	2000	Scotti, Spahr, McMillan, Larsen, Montani, Gleason, Gehrels	Retrograde irregular (Pasiphae)	Jupiter

-	XVIII	Themisto	4.0	7,284,000	130.02	1975/2000	Kowal and Roemer (original); Sheppard, Jewitt, Fernández, Magnier (rediscovery)	Prograde irregular (Themisto)	Jupiter

XIX	Megaclite	2.7	23,493,000	752.86 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Pasiphae)	Jupiter

XX	Taygete	2.5	23,280,000	732.41 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Carme)	Jupiter

XXI	Chaldene	1.9	23,100,000	723.72 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Carme)	Jupiter

XXII	Harpalyke	2.2	20,858,000	623.32 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Ananke)	Jupiter

XXIII	Kalyke	2.6	23,483,000	742.06 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Carme)	Jupiter

XXIV	Iocaste	2.6	21,060,000	631.60 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Ananke)	Jupiter

XXV	Erinome	1.6	23,196,000	728.46 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Carme)	Jupiter

XXVI	Isonoe	1.9	23,155,000	726.23 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Carme)	Jupiter

XXVII	Praxidike	3.4	20,908,000	625.39 (r)	2000	Sheppard, Jewitt, Fernández, Magnier, Dahm, Evans	Retrograde irregular (Ananke)	Jupiter

XXVIII	Autonoe	2.0	24,046,000	760.95 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Pasiphae)	Jupiter

XXIX	Thyone	2.0	20,939,000	627.21 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Ananke)	Jupiter

-	XXX	Hermippe	2.0	21,131,000	633.9 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Ananke)	Jupiter

XXXI	Aitne	1.5	23,229,000	730.18 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Carme)	Jupiter

XXXII	Eurydome	1.5	22,865,000	717.33 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Pasiphae)	Jupiter

XXXIII	Euanthe	1.5	20,797,000	620.49 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Ananke)	Jupiter

XXXIV	Euporie	1.0	19,304,000	550.74 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Ananke)	Jupiter

XXXV	Orthosie	1.0	20,720,000	622.56 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Ananke)	Jupiter

XXXVI	Sponde	1.0	23,487,000	748.34 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Pasiphae)	Jupiter

XXXVII	Kale	1.0	23,217,000	729.47 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Carme)	Jupiter

XXXVIII	Pasithee	1.0	23,004,000	719.44 (r)	2001	Sheppard, Jewitt, Kleyna	Retrograde irregular (Carme)	Jupiter

XXXIX	Hegemone	1.5	23,577,000	739.88 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Pasiphae)	Jupiter

XL	Mneme	1.0	21,035,000	620.04 (r)	2003	Gladman, Allen	Retrograde irregular (Ananke)	Jupiter

XLI	Aoede	2.0	23,980,000	761.50 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Pasiphae)	Jupiter

XLII	Thelxinoe	1.0	21,164,000	628.09 (r)	2003	Sheppard, Jewitt, Kleyna, Gladman, Kavelaars, Petit, Allen	Retrograde irregular (Ananke)	Jupiter

-	XLIII	Arche	1.5	23,355,000	731.95 (r)	2002	Sheppard, Meech, Hsieh, Tholen, Tonry	Retrograde irregular (Carme)	Jupiter

XLIV	Kallichore	1.0	23,288,000	728.73 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Carme)	Jupiter

XLV	Helike	2.0	21,069,000	626.32 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Ananke)	Jupiter

XLVI	Carpo	1.5	17,058,000	456.30	2003	Sheppard, Gladman, Kavelaars, Petit, Allen, Jewitt, Kleyna	Prograde irregular (Carpo)	Jupiter

XLVII	Eukelade	2.0	23,328,000	730.47 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Carme)	Jupiter

XLVIII	Cyllene	1.0	23,809,000	752 (r)	2003	Sheppard, Jewitt, Kleyna	Retrograde irregular (Pasiphae)	Jupiter

XLIX	Kore	1.0	24,543,000	779.17 (r)	2003	Sheppard, Jewitt, Kleyna	Retrograde irregular (Pasiphae)	Jupiter

L	Herse	1.0	22,983,000	714.51 (r)	2003	Gladman, Sheppard, Jewitt, Kleyna, Kavelaars, Petit, Allen	Retrograde irregular (Carme)	Jupiter

LI	S/2010 J 1	1.0	23,314,335	723.2 (r)	2010	Jacobson, Brozović, Gladman, Alexandersen	Retrograde irregular (Carme)	Jupiter

LII	S/2010 J 2	0.5	20,307,150	588.1 (r)	2010	Veillet	Retrograde irregular (Ananke)	Jupiter

LIII	Dia	2.0	12,570,000	287.93	2001	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Prograde irregular (Himalia)	Jupiter

LIV	S/2016 J 1	3.0	20,595,480	602.7 (r)	2016	Sheppard	Retrograde irregular (Ananke)	Jupiter

LV	S/2003 J 18	1.0	20,426,000	596.58 (r)	2003	Gladman, Sheppard, Jewitt, Kleyna, Kavelaars, Petit, Allen	Retrograde irregular (Ananke)	Jupiter

LVI	S/2011 J 2	0.5	23,329,710	726.8 (r)	2011	Sheppard	Retrograde irregular (Pasiphae)	Jupiter

LVII	S/2003 J 5	2.0	23,498,000	738.74 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Carme)	Jupiter

LVIII	S/2003 J 15	1.0	22,630,000	689.77 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Pasiphae)	Jupiter

LIX	S/2017 J 1	2.0	23,483,978	734.2 (r)	2017	Sheppard	Retrograde irregular (Pasiphae)	Jupiter

LX	S/2003 J 3	1.0	20,224,000	583.88 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Ananke)	Jupiter

LXI	S/2003 J 19	1.0	23,535,000	740.43 (r)	2003	Gladman, Sheppard, Jewitt, Kleyna, Kavelaars, Petit, Allen	Retrograde irregular (Carme)	Jupiter

-	LXII	Valetudo	0.5	18,928,095	532.0	2016	Sheppard	Prograde irregular (Valetudo)	Jupiter

LXIII	S/2017 J 2	1.0	23,240,957	723.8 (r)	2017	Sheppard	Retrograde irregular (Carme)	Jupiter

LXIV	S/2017 J 3	1.0	20,639,315	605.8 (r)	2017	Sheppard	Retrograde irregular (Ananke)	Jupiter

LXV	S/2017 J 4	1.0	11,494,801	251.8 (r)	2017	Sheppard	Prograde irregular (Himalia)	Jupiter

LXVI	S/2017 J 5	1.0	23,169,389	720.5 (r)	2017	Sheppard	Retrograde irregular (Carme)	Jupiter

LXVII	S/2017 J 6	1.0	22,394,682	684.7 (r)	2017	Sheppard	Retrograde irregular (Pasiphae)	Jupiter

LXVIII	S/2017 J 7	1.0	20,571,458	602.8 (r)	2017	Sheppard	Retrograde irregular (Ananke)	Jupiter

LXIX	S/2017 J 8	0.5	23,174,446	720.7 (r)	2017	Sheppard	Retrograde irregular (Carme)	Jupiter

LXX	S/2017 J 9	1.0	21,429,955	640.9 (r)	2017	Sheppard	Retrograde irregular (Ananke)	Jupiter

LXXI	S/2018 J 1	1.0	11,453,004	250.4 (r)	2018	Sheppard	Retrograde irregular (Himalia)	Jupiter

LXXII	S/2011 J 1	0.5	20,155,290	580.7 (r)	2011	Sheppard	Retrograde irregular (Carme)	Jupiter

—	S/2003 J 2	1.0	28,455,000	981.55 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Pasiphae?)	Jupiter

—	S/2003 J 4	1.0	23,933,000	755.26 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández, Hsieh	Retrograde irregular (Pasiphae?)	Jupiter

—	S/2003 J 9	0.5	23,388,000	733.30 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Carme)	Jupiter

—	S/2003 J 10	1.0	23,044,000	716.25 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Carme?)	Jupiter

—	S/2003 J 12	0.5	17,833,000	489.72 (r)	2003	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Ananke?)	Jupiter

—	S/2003 J 16	1.0	20,956,000	616.33 (r)	2003	Gladman, Sheppard, Jewitt, Kleyna, Kavelaars, Petit, Allen	Retrograde irregular (Ananke)	Jupiter

-	—	S/2003 J 23	1.0	23,566,000	732.45 (r)	2004	Sheppard, Jewitt, Kleyna, Fernández	Retrograde irregular (Pasiphae?)	Jupiter

-	I	Mimas	198.2 ± 0.4	185,540	0.942	1789	Herschel	Main-group moon	Saturn

-	II	Enceladus	252.3 ± 0.6	238,040	1.370	1789	Herschel	Main-group moon	Saturn

-	III	Tethys	536.3 ± 1.5	294,670	1.888	1684	Cassini	Main-group moon (Sidera Lodoicea)	Saturn

-	IV	Dione	562.5 ± 1.5	377,420	2.737	1684	Cassini	Main-group moon (Sidera Lodoicea)	Saturn

-	V	Rhea	764.5 ± 2.0	527,070	4.518	1672	Cassini	Main-group moon (Sidera Lodoicea)	Saturn

-	VI	Titan	2575.5 ± 2.0	1,221,870	15.95	1655	Huygens	Main-group moon	Saturn

-	VII	Hyperion	138.6	1,500,880	21.28	1848	W.Bond, G. Bond, and Lassell	Main-group moon	Saturn

-	VIII	Iapetus	734.5 ± 4.0	3,560,840	79.33	1671	Cassini	Main-group moon (Sidera Lodoicea)	Saturn

-	IX	Phoebe	106.6 ± 1.1	12,947,780	550.31 (r)	1899	Pickering	Retrograde irregular (Norse)	Saturn

-	X	Janus	90.4 ± 3.0	151,460	0.695	1966	Dollfus; Voyager 1 (confirmed)	Inner moon (co-orbital)	Saturn

-	XI	Epimetheus	58.3 ± 3.1	151,410	0.694	1980	Walker; Voyager 1 (confirmed)	Inner moon (co-orbital)	Saturn

-	XII	Helene	16 ± 4	377,420	2.737	1980	Laques, Lecacheux	Main-group trojan	Saturn

-	XIII	Telesto	12 ± 3	294,710	1.888	1980	Smith, Reitsema, Larson, Fountain (Voyager 1)	Main-group trojan	Saturn

-	XIV	Calypso	9.5 ± 1.5	294,710	1.888	1980	Pascu, Seidelmann, Baum, Currie	Main-group trojan	Saturn

-	XV	Atlas	15.3 ± 1.2	137,670	0.602	1980	Terrile (Voyager 1)	Inner moon (shepherd)	Saturn

-	XVI	Prometheus	46.8 ± 5.6	139,380	0.613	1980	Collins (Voyager 1)	Inner moon (shepherd)	Saturn

-	XVII	Pandora	40.6 ± 4.5	141,720	0.629	1980	Collins (Voyager 1)	Inner moon (shepherd)	Saturn

-	XVIII	Pan	12.8	133,580	0.575	1990	Showalter (Voyager 2)	Inner moon (shepherd)	Saturn

-	XIX	Ymir	9	23,140,400	1,315.58 (r)	2000	Gladman	Retrograde irregular (Norse)	Saturn

-	XX	Paaliaq	11	15,200,000	686.95	2000	Gladman	Prograde irregular (Inuit)	Saturn

-	XXI	Tarvos	7.5	17,983,000	926.23	2000	Gladman, Kavelaars	Prograde irregular (Gallic)	Saturn

-	XXII	Ijiraq	6	11,124,000	451.42	2000	Gladman, Kavelaars	Prograde irregular (Inuit)	Saturn

XXIII	Suttungr	3.5	19,459,000	1,016.67 (r)	2000	Gladman, Kavelaars	Retrograde irregular (Norse)	Saturn

-	XXIV	Kiviuq	8	11,110,000	449.22	2000	Gladman	Prograde irregular (Inuit)	Saturn

-	XXV	Mundilfari	3.5	18,628,000	952.77 (r)	2000	Gladman, Kavelaars	Retrograde irregular (Norse)	Saturn

XXVI	Albiorix	16	16,182,000	783.45	2000	Holman, Spahr	Prograde irregular (Gallic)	Saturn

XXVII	Skathi	4	15,540,000	728.20 (r)	2000	Gladman, Kavelaars	Retrograde irregular (Norse)	Saturn

XXVIII	Erriapus	5	17,343,000	871.19	2000	Gladman, Kavelaars	Prograde irregular (Gallic)	Saturn

XXIX	Siarnaq	20	18,015,400	896.44	2000	Gladman, Kavelaars	Prograde irregular (Inuit)	Saturn

-	XXX	Thrymr	3.5	20,314,000	1,094.11 (r)	2000	Gladman, Kavelaars	Retrograde irregular (Norse)	Saturn

-	XXXI	Narvi	3.5	19,007,000	1,003.86 (r)	2003	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

-	XXXII	Methone	1.6	194,440	1.010	2004	Porco, Charnoz, Brahic, Dones (Cassini–Huygens)	Alkyonide moon	Saturn

-	XXXIII	Pallene	2	212,280	1.154	2004	Gordon, Murray, Beurle, et al. (Cassini–Huygens)	Alkyonide moon	Saturn

-	XXXIV	Polydeuces	1.25	377,200	2.737	2004	Porco et al. (Cassini–Huygens)	Main-group trojan	Saturn

-	XXXV	Daphnis	3–4	136,500	0.594	2005	Porco et al. (Cassini–Huygens)	Inner moon (shepherd)	Saturn

XXXVI	Aegir	3	20,751,000	1,117.52 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

-	XXXVII	Bebhionn	3	17,119,000	834.84	2004	Sheppard, Jewitt, Kleyna, Marsden	Prograde irregular (Gallic)	Saturn

-	XXXVIII	Bergelmir	3	19,336,000	1,005.74 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

XXXIX	Bestla	3.5	20,192,000	1,088.72 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

XL	Farbauti	2.5	20,377,000	1,085.55 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

XLI	Fenrir	2	22,454,000	1,260.35 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

-	XLII	Fornjot	3	25,146,000	1,494.2 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

XLIII	Hati	3	19,846,000	1,038.61 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse)	Saturn

XLIV	Hyrrokkin	4	18,437,000	931.86 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

-	XLV	Kari	3.5	22,089,000	1,230.97 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

XLVI	Loge	3	23,058,000	1,311.36 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

XLVII	Skoll	3	17,665,000	878.29 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

XLVIII	Surtur	3	22,704,000	1,297.36 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

-	XLIX	Anthe	1	197,700	1.0365	2007	Porco et al. (Cassini–Huygens)	Alkyonide moon	Saturn

L	Jarnsaxa	3	18,811,000	964.74 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

LI	Greip	3	18,206,000	921.19 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse)	Saturn

LII	Tarqeq	3.5	18,009,000	887.48	2007	Sheppard, Jewitt, Kleyna	Prograde irregular (Inuit)	Saturn

-	LIII	Aegaeon	0.25	167,500	0.808	2008	Cassini Imaging Science Team Cassini–Huygens	G-ring moonlet	Saturn

—	S/2004 S 7	3	20,999,000	1,140.24 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse?)	Saturn

—	S/2004 S 12	2.5	19,878,000	1,046.19 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse?)	Saturn

—	S/2004 S 13	3	18,404,000	933.48 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse?)	Saturn

—	S/2004 S 17	2	19,447,000	1,014.70 (r)	2004	Sheppard, Jewitt, Kleyna, Marsden	Retrograde irregular (Norse?)	Saturn

—	S/2006 S 1	3	18,790,000	963.37 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse?)	Saturn

—	S/2006 S 3	3	22,096,000	1,227.21 (r)	2006	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse?)	Saturn

—	S/2007 S 2	3	16,725,000	808.08 (r)	2007	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse?)	Saturn

—	S/2007 S 3	3	18,975,000	977.8 (r)	2007	Sheppard, Jewitt, Kleyna	Retrograde irregular (Norse?)	Saturn

-	—	S/2009 S 1	0.15	117,000	0.471	2009	Cassini Imaging Science Team Cassini–Huygens	B-ring moonlet	Saturn

-	I	Ariel	578.9 ± 0.6	190,900	2.520	1851	Lassell	Main-group moon	Uranus

-	II	Umbriel	584.7 ± 2.8	266,000	4.144	1851	Lassell	Main-group moon	Uranus

-	III	Titania	788.9 ± 1.8	436,300	8.706	1787	Herschel	Main-group moon	Uranus

-	IV	Oberon	761.4 ± 2.6	583,500	13.46	1787	Herschel	Main-group moon	Uranus

-	V	Miranda	235.8 ± 0.7	129,900	1.413	1948	Kuiper	Main-group moon	Uranus

-	VI	Cordelia	20.1 ± 3	49,800	0.335	1986	Terrile (Voyager 2)	Inner moon (shepherd)	Uranus

-	VII	Ophelia	21.4 ± 4	53,800	0.376	1986	Terrile (Voyager 2)	Inner moon (shepherd)	Uranus

-	VIII	Bianca	25.7 ± 2	59,200	0.435	1986	Smith (Voyager 2)	Inner moon	Uranus

-	IX	Cressida	39.8 ± 2	61,800	0.464	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	X	Desdemona	32.0 ± 4	62,700	0.474	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	XI	Juliet	46.8 ± 4	64,400	0.493	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	XII	Portia	67.6 ± 4	66,100	0.513	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	XIII	Rosalind	36 ± 6	69,900	0.558	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	XIV	Belinda	40.3 ± 8	75,300	0.624	1986	Synnott (Voyager 2)	Inner moon	Uranus

-	XV	Puck	81 ± 2	86,000	0.762	1985	Synnott (Voyager 2)	Inner moon	Uranus

-	XVI	Caliban	49	7,231,100	579.73 (r)	1997	Gladman, Nicholson, Burns, Kavelaars	Retrograde irregular	Uranus

-	XVII	Sycorax	75	12,179,400	1,288.38 (r)	1997	Gladman, Nicholson, Burns, Kavelaars	Retrograde irregular	Uranus

-	XVIII	Prospero	25	16,256,000	1,978.29 (r)	1999	Gladman, Holman, Kavelaars, Petit, Scholl	Retrograde irregular	Uranus

-	XIX	Setebos	24	17,418,000	2,225.21 (r)	1999	Gladman, Holman, Kavelaars, Petit, Scholl	Retrograde irregular	Uranus

-	XX	Stephano	10	8,004,000	677.36 (r)	1999	Gladman, Holman, Kavelaars, Petit, Scholl	Retrograde irregular	Uranus

XXI	Trinculo	9	8,504,000	749.24 (r)	2001	Holman, Kavelaars, Milisavljevic	Retrograde irregular	Uranus

-	XXII	Francisco	6	4,276,000	266.56 (r)	2001	Holman, Kavelaars, Milisavljevic, Gladman	Retrograde irregular	Uranus

XXIII	Margaret	5.5	14,345,000	1,687.01	2003	Sheppard, Jewitt	Prograde irregular	Uranus

-	XXIV	Ferdinand	6	20,901,000	2,887.21 (r)	2001	Holman, Kavelaars, Milisavljevic, et al.	Retrograde irregular	Uranus

-	XXV	Perdita	15	76,417	0.638	1986	Karkoschka (Voyager 2)	Inner moon	Uranus

-	XXVI	Mab	6	97,736	0.923	2003	Showalter, Lissauer	Inner moon	Uranus

-	XXVII	Cupid	9	74,392	0.613	2003	Showalter, Lissauer	Inner moon	Uranus

-	I	Triton	1353.4 ± 0.9	354,800	5.877 (r)	1846	Lassell	Retrograde irregular	Neptune

-	II	Nereid	170 ± 25	5,513,820	360.14	1949	Kuiper	Prograde irregular	Neptune

-	III	Naiad	33 ± 3	48,224	0.294	1989	Terrile (Voyager 2)	Inner moon	Neptune

-	IV	Thalassa	41 ± 3	50,075	0.311	1989	Terrile (Voyager 2)	Inner moon	Neptune

-	V	Despina	75 ± 3	52,526	0.335	1989	Synnott (Voyager 2)	Inner moon	Neptune

-	VI	Galatea	88 ± 4	61,953	0.429	1989	Synnott (Voyager 2)	Inner moon	Neptune

-	VII	Larissa	97 ± 3	73,548	0.555	1982	Reitsema, Hubbard, Lebofsky, Tholen (Voyager 2)	Inner moon	Neptune

-	VIII	Proteus	210 ± 7	117,647	1.122	1989	Synnott (Voyager 2)	Inner moon	Neptune

-	IX	Halimede	31	15,728,000	1,879.71 (r)	2002	Holman, Kavelaars, Grav, Fraser, Milisavljevic	Retrograde irregular	Neptune

-	X	Psamathe	20	46,695,000	9,115.91 (r)	2003	Jewitt, Kleyna, Sheppard, Holman, Kavelaars	Retrograde irregular	Neptune

XI	Sao	22	22,422,000	2,914.07	2002	Holman, Kavelaars, Grav, Fraser, Milisavljevic	Prograde irregular	Neptune

XII	Laomedeia	21	23,571,000	3,167.85	2002	Holman, Kavelaars, Grav, Fraser, Milisavljevic	Prograde irregular	Neptune

XIII	Neso	30	48,387,000	9,373.99 (r)	2002	Holman, Kavelaars, Grav, Fraser, Milisavljevic	Retrograde irregular	Neptune

-	XIV	Hippocamp	17.4	105,283	0.9362	2013	Showalter et al.	Inner moon	Neptune

-	I	Charon	606 ± 0.5	19,591	6.387	1978	Christy	Pluto

-	II	Nix	23.0 ± 2	48,671	24.85	2005	Weaver, Stern, Buie, et al.	Pluto

-	III	Hydra	30.5 ± 4	64,698	38.20	2005	Weaver, Stern, Buie, et al.	Pluto

-	IV	Kerberos	14.0	57,729	32.17	2011	Showalter (Hubble)	Pluto

-	V	Styx	10.0	42,393	20.16	2012	Showalter (Hubble)	Pluto

I	Hiʻiaka	~160	49,880	49.12 ± 0.03	2005	Brown et al.	Haumea

II	Namaka	~85	25,657	18.2783	2005	Brown et al.	Haumea

-	—	S/2015 (136472) 1	~87.5	~21,000	~12.4	2016	Parker et al.	Makemake

-	I	Dysnomia	350 ± 60	37,370 ± 150	15.774 ± 0.002	2005	Brown, Rabinowitz, Trujillo et al.	SDO moon	Eris

Sentence(s)

Io is the fourth moon in the Solar System.

final_sentence: Io is the fourth moon in the Solar System.