Solar system objects: physical data and discovery dates

Solar System Objects: Physical Data and Discovery Dates

compiled by Wm. Robert Johnston
last updated 7 February 2006

Table includes the following solar system objects:

the Sun and all major planets;
all planetary satellites;
all asteroids and trans-Neptunian objects with estimated diameters of at least 300 km;
selected asteroids and trans-Neptunian objects with satellites; and
asteroids and comets which have been targeted by space probes.

ID indicates star (*), planet (P), planetary satellite (S), asteroid (A), trans-Neptunian object (T), satellite of asteroid or trans-Neptunian object (M), or comet (C). For diameter/axial dimension figures, one figure is average diameter; two figures (a x b) are equatorial and polar diameters; and three figures (a x b x c) are triaxial ellipsoid axes. Under rotation period, negative figures indicate retrograde rotation and "SYN" indicates synchronous rotation with respect to primary.

object	id	diameter/axial dimensions (km)			density	mass	surface gravity	rotation period	discovery date
object	id	a or eq.	b or pol.	c	(kg/m³)	(Earth=1)	(Earth=1)	(days)	discovery date
SUN	*	1391000			1409	332946	27.89	25.38	N/A
MERCURY	P	4881	4878	4878	5427	0.0053	0.377	58.6462	N/A
VENUS	P	12103	12103		5244.8	0.815	0.903	-243.0198	N/A
1999 HF1	A	3.7			2000	7.5E-12	0.0001	0.09663	20 APR 1999
N/A	M	0.8							23 APR 1999
EARTH	P	12756	12714		5514.8	1.000000	1.000000	0.99726968	N/A
Moon	S	3477	3476	3475	3344	0.0123001	0.165	SYN	N/A
1996 FG3	A	1.5	1.3	1	1400	3.5E-13	0.00002	0.14973	24 MAR 1996
N/A	M	0.45	0.3	0.3	1400				10 DEC 1998
(25143) Itokawa	A	0.69	0.29	0.26	2300	6.8E-15	0.000012	0.54	26 SEP 1998
2000 DP107	A	0.9	0.8		1700	7.7E-14	0.00002	0.1156	29 FEB 2000
S/2000 (2000 DP107) 1	M	0.3	0.25					SYN	22 SEP 2000
(433) Eros	A	34.4	11.2	11.2	2670	1.115E-9	0.0004	0.219594	13 AUG 1898
(1862) Apollo	A	1.8	1.4					0.12773	24 APR 1932
N/A	M	0.08							29 OCT 2005
MARS	P	6797	6788	6752	3933.5	0.1074	0.379	1.02595675	N/A
Phobos	S	27	22	19	1870	1.79E-9	0.0006	SYN	11 AUG 1877
Deimos	S	15	12	11	2250	3.8E-10	0.0004	SYN	17 AUG 1877
(69230) Hermes	A	0.4						0.5788	28 OCT 1937
N/A	M	0.4						SYN	18 OCT 2003
(5407) 1992 AX	A	4						0.1062	4 JAN 1992
N/A	M	1.5							7 JAN 1997
(4674) Pauling	A	8							2 MAY 1989
S/2004 (4674) 1	M	2.5							4 MAR 2004
(1509) Esclangona	A	12						0.11	21 DEC 1938
S/2003 (1509) 1	M	4							13 FEB 2003
(3671) Dionysus	A	0.9			1600	4.7E-13	0.00002	0.1127	27 MAY 1984
S/1997 (3671) 1	M	0.3							30 MAY 1997
(951) Gaspra	A	18.2	10.5	8.9					30 JUL 1916
(5535) Annefrank	A	6.6	5.0	3.4					23 MAR 1942
(3749) Balam	A	7			1200	2.5E-11	0.0001		24 JAN 1982
S/2002 (3749) 1	M	1.5							8 FEB 2002
(9969) Braille	A	2.1	1.0	1.0				9.4	27 MAY 1992
(4) Vesta	A	578	560	458	3900	0.000051	0.029	0.2225887	29 MAR 1807
(4179) Toutatis	A	4.6	2.3	1.9					4 JAN 1989
(253) Mathilde	A	66	48	44	1300	1.7E-8	0.00049	17.4	12 NOV 1885
(45) Eugenia	A	290	220	160	1100	0.00000097	0.003	0.2374647	27 JUN 1857
Petit-Prince	M	13							1 NOV 1998
(1) Ceres	A	950	920		1980	0.00014	0.026	0.3781	1 JAN 1801
(2) Pallas	A	570	525	482	4200	0.000053	0.031	0.32555136	28 MAR 1802
(243) Ida	A	60	25	19	2700	0.000000007	0.001	0.193068	29 SEP 1884
Dactyl	M	1.6	1.4	1.2					28 AUG 1993
(22) Kalliope	A	230	180	150	2030	0.00000123	0.005	0.1728416	16 NOV 1852
Linus	M	36							29 AUG 2001
(283) Emma	A	150			870	0.00000025	0.002	0.287	8 FEB 1889
S/2003 (283) 1	M	12							14 JUL 2003
(704) Interamnia	A	340	290					0.3636	1 OCT 1910
(52) Europa	A	320	280					0.2347	4 FEB 1858
(130) Elektra	A	215	155		3800	0.0000021	0.010	0.2177	17 FEB 1873
S/2003 (130) 1	M	4							15 AUG 2003
9P/Temple 1	C							1.74	3 APR 1867
(379) Huenna	A	93			1200	0.000000079	0.002	0.2926	8 JAN 1894
S/2003 (379) 1	M	7							14 AUG 2003
(10) Hygeia	A	450	370					1.151	12 APR 1849
(90) Antiope	A	110			1000	0.000000069	0.002	0.6873	1 OCT 1866
S/2000 (90) 1	M	110			1000	0.000000069	0.002	SYN	10 AUG 2000
(511) Davida	A	350	300					0.2137	30 MAY 1903
(121) Hermione	A	220	200	200	1800	0.0000015	0.005	0.3849	12 MAY 1872
S/2002 (121) 1	M	13							28 SEP 2002
81P/Wild 2	C	5.5	4	3.3	400	2.5E-12	0.00002		6 JAN 1978
(107) Camilla	A	340	230	140	1880	0.00000182	0.006	0.2018306	17 NOV 1868
S/2001 (107) 1	M	9							1 MAR 2001
(87) Sylvia	A	380	260	230	1200	0.00000246	0.005	0.2159853	16 MAY 1866
Remus	M	7							9 AUG 2004
Romulus	M	18							18 FEB 2001
19P/Borrelly	C	8	3					1.1	28 DEC 1904
JUPITER	P	142796	133540		1326	317.8284	2.635	0.41351	N/A
Metis	S	60	40	34				SYN	4 MAR 1980
Adrastea	S	24	20	16				SYN	8 JUL 1979
Amalthea	S	250	146	128	900	3.5E-7	0.002	SYN	9 SEP 1892
Thebe	S	116	98	84				SYN	5 MAR 1979
Io	S	3659	3638	3632	3529.4	0.014952	0.183	SYN	8 JAN 1610
Europa	S	3125	3120	3119	2984	0.008035	0.133	SYN	8 JAN 1610
Ganymede	S	5270	5268	5267	1940	0.024806	0.145	SYN	7 JAN 1610
Callisto	S	4817	4816		1851	0.018011	0.127	SYN	7 JAN 1610
Themisto	S	8							30 SEP 1975
Leda	S	10							10 SEP 1974
Himalia	S	170						0.396	3 NOV 1904
Lysithea	S	24							6 JUL 1938
Elara	S	80						0.5	2 JAN 1905
S/2000 J11	S	4							5 DEC 2000
Carpo	S	3							9 FEB 2003
S/2003 J3	S	2							5 FEB 2003
S/2003 J12	S	1							8 FEB 2003
Euporie	S	2							11 DEC 2001
Mneme	S	2							6 FEB 2003
S/2003 J18	S	2							6 FEB 2003
Helike	S	4							6 FEB 2003
S/2003 J16	S	2							6 FEB 2003
Euanthe	S	3							11 DEC 2001
Harpalyke	S	4							23 NOV 2000
Praxidike	S	7							23 NOV 2000
Thelxinoe	S	2							2003
Orthosie	S	2							8 DEC 2001
Hermippe	S	4							9 DEC 2001
Iocaste	S	5							23 NOV 2000
Ananke	S	20							29 SEP 1951
Thyone	S	4							12 DEC 2001
S/2003 J15	S	2							6 FEB 2003
S/2003 J17	S	2							8 FEB 2003
Kallichore	S	2							6 FEB 2003
S/2003 J9	S	2							6 FEB 2003
S/2003 J19	S	2							6 FEB 2003
Pasithee	S	2							11 DEC 2001
Arche	S	3							31 OCT 2002
Isonoe	S	4							23 NOV 2000
Kale	S	2							9 DEC 2001
Chaldene	S	4							26 NOV 2000
Eurydome	S	3							9 DEC 2001
S/2003 J4	S	2							5 FEB 2003
Erinome	S	3							23 NOV 2000
Taygete	S	5							25 NOV 2000
Carme	S	30							30 JUL 1938
Aitne	S	3							9 DEC 2001
Kalyke	S	5							23 NOV 2000
Pasiphae	S	36							27 JAN 1908
Megaclite	S	5							25 NOV 2000
Aoede	S	4							8 FEB 2003
Sponde	S	2							9 DEC 2001
Sinope	S	28							21 JUL 1914
Cyllene	S	2							9 FEB 2003
S/2003 J23	S	2							6 FEB 2003
S/2003 J5	S	4							6 FEB 2003
Callirrhoe	S	12							6 OCT 1999
Autonoe	S	4							10 DEC 2001
S/2003 J10	S	2							6 FEB 2003
Hegemone	S	3							8 FEB 2003
Eukelade	S	4							5 FEB 2003
S/2003 J14	S	2							8 FEB 2003
S/2003 J2	S	2							5 FEB 2003
(617) Patroclus	A	105			1300	1.3E-7	0.002	SYN?	17 OCT 1906
S/2001 (617) 1	M	95			1300	1.0E-7	0.002	SYN?	22 SEP 2001
SATURN	P	120660	107670		687.3	95.1609	1.136	0.444009	N/A
Pan	S	26						SYN	16 JUL 1990
Daphnis	S	7							MAY 2005
Atlas	S	37	34	27				SYN	OCT 1989
Prometheus	S	148	100	68				SYN	OCT 1989
S/2004 S4	S	5							21 JUN 2004
S/2004 S6	S	5							28 OCT 2004
S/2004 S3	S	5							21 JUN 2004
Pandora	S	110	88	62				SYN	OCT 1989
Epimetheus	S	138	110	106	610	9.0E-8	0.001	SYN	26 FEB 1980
Janus	S	199	191	151	650	3.22E-7	0.002	SYN	15 DEC 1966
Mimas	S	405	396	393	1120	6.3E-6	0.006	SYN	17 SEP 1789
Methone	S	3							1 JUN 2004
Pallene	S	4							1 JUN 2004
Enceladus	S	507	495	491	1000	0.0000109	0.007	SYN	28 AUG 1789
Tethys	S	1071	1056	1052	990	0.000105	0.015	SYN	21 MAR 1684
Telesto	S	30	25	15				SYN	8 APR 1980
Calypso	S	30	16	16				SYN	13 MAR 1980
Polydeuces	S	4							21 OCT 2004
Dione	S	1120	1120		1490	0.000184	0.024	SYN	21 MAR 1684
Helene	S	35	32	20				SYN	1 MAR 1980
Rhea	S	1528	1528		1240	0.000386	0.027	SYN	23 DEC 1672
Titan	S	5150	5150		1881	0.022524	0.138	SYN	25 MAR 1655
Hyperion	S	370	280	226	1100	1.8E-6	0.004		19 SEP 1848
Iapetus	S	1436	1436		1300	0.00027	0.027	SYN	25 OCT 1671
Kiviuq	S	19							7 AUG 2000
Ijiraq	S	15							23 SEP 2000
Phoebe	S	229	213	212	1630	1.48E-6	0.005	0.392	16 AUG 1898
Paaliaq	S	31							7 AUG 2000
Skathi	S	11							23 SEP 2000
Albiorix	S	30							12 DEC 2000
S/2004 S11	S	6							2004
Erriapo	S	13							23 SEP 2000
Siarnaq	S	56							23 SEP 2000
Tarvos	S	19							23 SEP 2000
Mundilfari	S	8							23 SEP 2000
S/2004 S13	S	6							2004
S/2004 S17	S	4							2004
S/2004 S15	S	6							2004
Narvi	S	8							5 FEB 2003
S/2004 S10	S	6							2004
Suttungr	S	7							22 DEC 2000
S/2004 S12	S	5							2004
S/2004 S18	S	7							2004
S/2004 S7	S	6							2004
S/2004 S9	S	5							2004
Thrymr	S	8							23 SEP 2000
S/2004 S14	S	6							2004
S/2004 S8	S	6							2004
S/2004 S16	S	4							2004
Ymir	S	25							7 AUG 2000
1P/Halley	C	15.3	7.2	7.2	260	1.8E-11	3E-6	2.24	N/A
URANUS	P	51120	49950		1318	14.5357	0.951	-0.7183	13 MAR 1781
Cordelia	S	26						SYN	20 JAN 1986
Ophelia	S	26						SYN	20 JAN 1986
Bianca	S	44						SYN	23 JAN 1986
Cressida	S	66						SYN	9 JAN 1986
Desdemona	S	58						SYN	13 JAN 1986
Juliet	S	84						SYN	3 JAN 1986
Portia	S	110						SYN	3 JAN 1986
Rosalind	S	58						SYN	13 JAN 1986
Cupid	S	12						SYN?	25 AUG 2003
Belinda	S	68						SYN	13 JAN 1986
Perdita	S	20						SYN?	1986
Puck	S	154						SYN	30 DEC 1985
Mab	S	15						SYN?	10 JUL 2003
Miranda	S	480	468	466	1200	0.000011	0.008	SYN	1 MAR 1948
Ariel	S	1162	1156	1155	1670	0.00023	0.028	SYN	24 OCT 1851
Umbriel	S	1169	1169		1400	0.00020	0.023	SYN	24 OCT 1851
Titania	S	1578	1578		1710	0.000590	0.038	SYN	11 JAN 1787
Oberon	S	1523	1523		1630	0.000505	0.035	SYN	11 JAN 1787
Francisco	S	15							13 AUG 2001
Caliban	S	60							6 SEP 1997
Stephano	S	20							18 JUL 1999
Trinculo	S	20							13 AUG 2001
Sycorax	S	120							6 SEP 1997
Margaret	S	20							29 AUG 2003
Prospero	S	30							17 JUL 1999
Setebos	S	30							18 JUL 1999
Ferdinand	S	20							13 AUG 2001
NEPTUNE	P	49530	48680		1638	17.1478	1.148	0.6713	23 SEP 1846
Naiad	S	66						SYN	AUG 1989
Thalassa	S	80						SYN	AUG 1989
Despina	S	148						SYN	JUL 1989
Galatea	S	176						SYN	JUL 1989
Larissa	S	208	178					SYN	JUL 1989
Proteus	S	436	416	402				SYN	JUN 1989
Triton	S	2705	2705		2054	0.00358	0.079	SYN	10 OCT 1846
Nereid	S	340							24 FEB 1949
S/2002 N1	S	54							10 AUG 2002
S/2002 N2	S	44							23 JUL 2002
S/2002 N3	S	44							11 AUG 2002
Psamathe	S	34							1 SEP 2003
S/2002 N4	S	60							14 AUG 2002
(78799) 2002 XW93	T	350							10 DEC 2002
(35671) 1998 SN165	T	300							23 SEP 1998
(120348) 2004 TY364	T	550							3 OCT 2004
(119951) 2002 KX14	T	580							17 MAY 2002
2002 VU130	T	330							7 NOV 2002
(55638) 2002 VE95	T	380							14 NOV 2002
(47171) 1999 TC36	T	380			700	0.0000023	0.004	0.3	1 OCT 1999
S/2001 (47171) 1	M	140							8 DEC 2001
2002 XV93	T	440							10 DEC 2002
2001 QF298	T	510							19 AUG 2001
(84719) 2002 VR128	T	320							3 NOV 2002
(84922) 2003 VS2	T	640							14 NOV 2003
2001 RU143	T	300							12 SEP 2001
(15789) 1993 SC	T	360						0.32	17 SEP 1993
(90482) Orcus	T	1530							17 FEB 2004
PLUTO	P	2390	2390		2030	0.0021	0.069	-6.3867	2 MAR 1930
Charon	S	1207	1207		1660	0.00026	0.028	SYN	22 JUN 1978
S/2005 P2	S	100							2005
S/2005 P1	S	130							2005
2001 XD255	T	350							9 DEC 2001
2003 AZ84	T	730							13 JAN 2003
2002 GF32	T	320							8 APR 2002
(28978) Ixion	T	890							22 MAY 2001
2001 KD77	T	300							24 MAY 2001
(38628) Huya	T	540							10 MAR 2000
2004 PT107	T	330							13 AUG 2004
(24835) 1995 SM55	T	700							19 SEP 1995
2002 MS4	T	770							18 JUN 2002
(120347) 2004 SB60	T	580							22 SEP 2004
2002 GH32	T	300							8 APR 2002
(90568) 2004 GV9	T	700							13 APR 2004
2002 VT130	T	330							7 NOV 2002
2001 YH140	T	350							18 DEC 2001
(55637) 2002 UX25	T	840							30 OCT 2002
2001 QD298	T	330							19 AUG 2001
2003 QA112	T	300							26 AUG 2003
2005 JA175	T	320							10 MAY 2005
2001 QO297	T	300							19 AUG 2001
(20000) Varuna	T	970						0.264	28 NOV 2000
2001 XR254	T	330							10 DEC 2001
(55636) 2002 TX300	T	810							15 OCT 2002
(19308) 1996 TO66	T	900						0.26	12 OCT 1996
(120178) 2003 OP32	T	670							26 JUL 2003
2002 GV31	T	380							6 APR 2002
2003 EL61	T	1960	1520	1000	3000	0.0007	0.061		7 MAR 2003
S/2005 (2003 EL61) 2	M	170							30 JUN 2005
S/2005 (2003 EL61) 1	M	310							2005
2005 JP179	T	300							11 MAY 2005
(50000) Quaoar	T	1260						0.73662	4 JUN 2002
2003 QW90	T	580							23 AUG 2003
1999 CD158	T	420							10 FEB 1999
2002 PQ145	T	330							9 AUG 2002
2001 QS297	T	370							20 AUG 2001
2001 QY297	T	370							21 AUG 2001
2001 QS322	T	370							19 AUG 2001
2002 XH91	T	350							4 DEC 2002
(79360) 1997 CS29	T	310							3 FEB 1997
N/A	M	290							22 OCT 2002
2003 UZ117	T	400							24 OCT 2003
2003 WU188	T	300							24 NOV 2003
2001 UQ18	T	370							20 OCT 2001
2003 QA91	T	380							24 AUG 2003
2003 GH55	T	320							1 APR 2003
1998 WW31	T	150			1500	0.00000017	0.003		18 NOV 1998
S/2000 (1998 WW31) 1	M	130			1500	0.00000011	0.003		22 DEC 2000
2002 GJ32	T	350							8 APR 2002
2000 CN105	T	440							6 FEB 2000
2002 GD32	T	330							7 APR 2002
2003 QM91	T	380							25 AUG 2003
2002 PJ149	T	380							11 AUG 2002
2001 CZ31	T	320							3 FEB 2001
(19521) Chaos	T	750							19 NOV 1998
2005 FY9	T	1500							31 MAR 2005
2004 PR107	T	530							11 AUG 2004
2003 MW12	T	770							21 JUN 2003
2002 CY248	T	420							6 FEB 2002
2003 UB292	T	320							23 OCT 2003
2002 KW14	T	530							17 MAY 2002
2000 CO105	T	370							5 FEB 2000
(55565) 2002 AW197	T	790							10 JAN 2002
2001 KA77	T	380							24 MAY 2001
(119979) 2002 WC19	T	420							16 NOV 2002
2000 AF255	T	300							6 JAN 2000
(40314) 1999 KR16	T	300						0.245	16 MAY 1999
(120132) 2003 FY128	T	440							26 MAR 2003
(42301) 2001 UR163	T	640							21 OCT 2001
2001 QW297	T	320							20 AUG 2001
(48639) 1995 TL8	T	350							15 OCT 1995
N/A	M	160							9 NOV 2002
2002 JR146	T	350							7 MAY 2002
(79978) 1999 CC158	T	300							15 FEB 1999
(84522) 2002 TC302	T	1200							9 OCT 2002
(26375) 1999 DE9	T	510						0.5	20 FEB 1999
2004 XR190	T	550							11 DEC 2004
(82075) 2000 YW134	T	430							26 DEC 2000
N/A	M	240							25 OCT 2002
2001 QX322	T	320							19 AUG 2001
2003 UB313	T	3000							21 OCT 2003
S/2005 (2003 UB313) 1	M	350							10 SEP 2005
(15874) 1996 TL66	T	630							9 OCT 1996
(26181) 1996 GQ21	T	400							12 APR 1996
C/1995 O1 Hale-Bopp	C	40							23 JUL 1995
(90377) Sedna	T	1700						0.428	14 NOV 2003