Asteroid's

On the first day of 1801 Giuseppe Piazzi found a new object which he thought was a comet. Once this object's orbit was determined it was found it,s orbit was more like a planet. Piazzi named it Ceres after the Sicilian goddess of grain. Over the next few years Pallas, Vestra and Juno were all discovered. By the end of the 19th Century there were several hundred. Several thousand have been found to date and are given provisonal designations so far. Thousands more are discovered each year. There is with no doubt that there are many more that are to small too be seen from Earth. There are 26 asteroids known larger than 200km, Astronomer's think that we know 99% of the asteriod's larger than 100km. Also, asteriod's between 10 to 100km in size. We think we know about half of these. But we know only a few of Asteriod's of those under 1 km and there could be millions more. To date the total mass of all the Asteriod's is less than our Moon in total.

Astronomer's used to dismiss as uninteresting an vermin. But now we know that these small rocky bodies hold important clues to the birth of the solar system. They have been linked to the end of the dinosuars and maybe even the end of Civilistion. These bodies are also called minor bodies with widely different distances from the Sun. From Inside the Earth's orbit to beyond Saturn. Most do orbit in the main belt between Mars and Jupiter. But in Total 10,000 have been discovered and named or named so far. The larger can be seen in backyard telescopes. Other are found on long exposure astrophotos appearing as a streak. Other's are seen when they cross a star and cause an occultation. They are possibly a planet that did not form because of perturbations of Jupiter. The largest is Ceres it is 933km in diameter and comtains 25% of the mass of all the other asteroid's combined. The next largest are 2 Pallas, 4 Vestra and 10 Hygiea which are btween 400 and 525km in Diameter. All the other known asteroid's are less than 340km in diameter.

Asteroid Number and Name	Diameter (km)	~Mass 10¹⁵ kg	Rotation Period	Orbital Period	Spectral Class	Semimajor Axis	Orbital Eccentricity	Orbital Inclination	Asteroid Number and Name
1 Ceres	960 x 932	870,000	9.075 hrs	4.60 yrs	C	2.767 AU	10.58 deg	0.0789	1 Ceres
2 Pallas	570 x 525 x 482	318,000	7.811 hrs	4.61 yrs	U	2.774 AU	0.2299	34.84 deg	2 Pallas
3 Juno	240	20,000	7.210 hrs	4.36 yrs	S	2.669 AU	0.2579	12.97 deg	3 Juno
4 Vesta	530	300,000	5.342 hrs	3.63 yrs	U	2.362 AU	0.0895	7.14 deg	4 Vesta
45 Eugenia	226	6,100	5.699 hrs	4.49 yrs	FC	2.721 AU	0.0831	6.61 deg	45 Eugenia
140 Siwa	103	1,500	18.5 hrs	4.51 yrs	C	2.734 AU	0.2157	3.19 deg	140 Siwa
216 Kleopatra	217 x 94	Unkown.	5.385 hrs	4.67 yrs	M	2.793 AU	0.2535	13.14 deg	216 Kleopatra
243 Ida	58 x 23	100	4.633 hrs	4.84 yrs	S	2.861 AU	0.0451	1.14 deg	243 Ida
253 Mathilde	66 x 48 x 46	103.3	417.7 hrs	4.31 yrs	C	2.646 AU	0.2660	6.71 deg	253 Mathilde
433 Eros	33 x 13 x 13	7.2	5.270 hrs	1.76 yrs	S	1.458 AU	0.2229	10.83 deg	433 Eros
951 Gaspra	19 x 12 x 11	10	7.042 hrs	3.29 yrs	S	2.209 AU	0.1738	4.10 deg	951 Gaspra
1566 Icarus	1.4	0.001	2.273 hrs	1.12 yrs	U	1.078 AU	0.8269	22.86 deg	1566 Icarus
1620 Geographos	2.0	0.004	5.222 hrs	1.39 yrs	S	1.245 AU	0.3356	13.34 deg	1620 Geographos
1862 Apollo	1.6	0.002	3.063 hrs	1.81 yrs	S	1.471 AU	0.5600	6.36 deg	1862 Apollo
2060 Chiron	180	4000	5.9 hrs	50.7 yrs	B	13.633 AU	0.3801	6.94 deg	2060 Chiron
2530 Shipka	Unkown.	Unkown.	Unkown.	5.25 yrs	Unkown.	3.019 AU	0.1237	10.10 deg	2530 Shipka
2703 Rodari	Unkown.	Unkown.	Unkown.	3.25 yrs	Unkown.	2.194 AU	0.0572	6.04 deg	2703 Rodari
3352 McAuliffe	2 - 5	Unkown.	Unkown.	2.57 yrs	Unkown.	1.879 AU	0.3686	4.77 deg	3352 McAuliffe
3840 Mimistrobell	Unkown.	Unkown.	Unkown.	3.38 yrs	Unkown.	2.249 AU	0.0831	3.92 deg	3840 Mimistrobell
4179 Toutatis	4.6 x 2.4 x 1.9	0.05	130. hrs	3.98 yrs	S	2.512 AU	0.6339	0.47 deg	4179 Toutatis
4660 Nereus	2	Unkown.	Unkown.	1.82 yrs	Unkown.	1.490 AU	0.3603	1.42 deg	4660 Nereus
4769 Castalia	Unkown.	1.8 x 0.8	0.0005	1.10 yrs	Unkown.	1.063 AU	0.4831	8.89 deg	4769 Castalia
4979 Otawara	Unkown.	5.5	0.2	3.19 yrs	Unkown.	2.168 AU	0.1449	0.91 deg	4979 Otawara
9969 Braille	2.2 x 1.0	Unkown.	Unkown.	3.58 yrs	Unkown.	2.341 AU	0.4336	29.0 deg	9969 Braille

A chart of some asteroids. There ia a debate to how to classifiy asteroids,comets and moons. Many moons are probably captured asteroids like the moons of Mars and many of the smaller moons of the gas giant's. Asteroids are classified into a number of types according to their spectra and their albedo.

C-TYPE: this class is has 75% of all the known asteroids. They are dark only having an albedo of 0.03 and are similar to caronceaous Chondrite meteroites; approximately the same chemical composition as our sun but with no hydrogen.

Mathilde
Catalogue No.: 253
Dimensions: 66x48x46 km
Density: 1.3
Class: C
Rotation: 17.4 days
This is the largest asteroid yet visited and also one of the slowest rotators. Its low density can only be explained by its porous composition.

S-TYPE:make up 17% and are quite bright, their albedio is 10-22 and are made of a metallic nickel-iron mixed with iron and magnesium-silicates.

Ida & Dactyl
Catalogue No.: 243
Dimensions: 56x24x21 km
Density: 2.5
Class: S
Rotation:4.63 hours This asteroid was passed by by the Galileo probe. This asteroid is notable for having a satellite, Dactyl that is only 1.4 km in diameter. It is not known how Dacyl was formed and how it became a satellite to Ida.

Toutatis
Catalogue No.: 4179
Dimensions: 4.5x2.4x1.9 km
Density: 2.1
Class: S
Rotation: Two separate periods ( 5.41 and 7.35 days ) Due to Earth's gravity it's orbit is chaotic. It also wobbles along different axes that combine and create nonperiodic rotation. On Septermber 29 2004 it will come within four lunar distances, close enough to see with binoculars.

Castalia
Catalogue No.: 4769
Dimensions: 1.8x0.8x0.8 km
Density: 2.1
Class: S
Rotation: 4 hours
Castalia was the first ever asteroid to be imaged. This occurred in 1989 when passed within eleven lunar distances of Earth and was imaged by radar from the Arecibo observatory in Puerto Rico.

M-TYPE:Most of the rest, bright albedo 10-18 and are made of pure nickel-iron.

Kleopatra
Cataloge No.: 216
Dimensions: 217 x 94
Density:Unkown
Rotation: 5.3 hours
Cass: M

Their are a few dozen of some rare types asteroids.
Extra Information:There are also the so-called "Trojan" asteroids that revolve in Jupiter's orbit. These are D class and are similar in composition to C class asteroids. There are also a few V class bodies that are made of igneous material.

Vesta
Catalogue No.: 4
Dimensions: 525 km in diameter.
Density: 3.3g/cm cubed
Class: V
Rotation: 5.34 hours.
The largest of the V class asteroids ( it is made of basaltic rock ) and also one of the first discovered.
There are a few classification schemes in use today but because of observation biases the percentage may not be only a representation of the true distribution of asteriods.

Asteroids are categorized by their position in the solar system:

Main Belt:These are found btweeen Mars and Jupiter Mars about 2-4 AU From the Sun. They are then shorted into sub groups: Hungarias, Floras, Phocaea, Koronis, Eros, Themis, Cybeles and Hildas. These are named after main belt Astroids.

Near Earth Asteroids:(NEAs) These are Asteroids that come close to the Earth. These are split into sub groups.

Asteroid Number and Name	Closest Approach Date	Closest Approach (AU)	H Abs Mag	Approx Diameter (meters)	Orbital Period (yrs)	Semimajor Axis (AU)	Orbital Eccentricity	Orbital Inclination (deg)	Numberand Name
1998 WT24	2001 Dec 16	0.0124	17.7	1250	0.61	0.718	0.418	7.4	1998 WT24
4660 Nereus	2002 Jan 22	0.0290	18.3	950	1.82	1.489	0.360	1.4	4660 Nereus
1998 FH12	2003 Jun 27	0.0495	19.0	680	1.14	1.093	0.540	3.5	1998 FH12
1994 PM	2003 Aug 16	0.0250	17.8	1200	1.80	1.479	0.753	18.0	1994 PM
1998 FG2	2003 Oct 21	0.0360	21.5	220	1.48	1.299	0.356	4.1	1998 FG2
1996 GT	2003 Nov 12	0.0479	18.5	860	2.10	1.642	0.383	3.4	1996 GT
1998 SF36	2004 Jun 26	0.0137	18.8	750	1.53	1.325	0.280	1.7	1998 SF36
1999 MN	2004 Jul 11	0.0174	21.6	200	0.55	0.674	0.664	2.0	1999 MN
4179 Toutatis	2004 Sep 29	0.0104	15.3	4600 x 2400	1.10	2.511	0.634	0.5	4179 Toutatis
1992 UY4	2005 Aug 8	0.0404	18.0	1100	4.33	2.657	0.620	2.8	1992 UY4
4450 Pan	2008 Feb 19	0.0408	17.2	1570	3.00	1.442	0.587	5.5	4450 Pan
2000 UG11	2008 Nov 9	0.0089	20.4	360	2.67	1.923	0.570	8.9	2000 UG11
1999 AQ10	2009 Feb 18	0.0118	20.4	360	0.91	0.937	0.234	6.6	1999 AQ10
1994 CC	2009 Jun 10	0.0169	18.0	1100	2.09	1.637	0.417	4.6	1994 CC
2001 FE90	2009 Jun 28	0.0185	19.8	470	2.68	1.929	0.495	8.8	2001 FE90
1999 MN	2010 Jun 2	0.0076	21.6	200	0.55	0.674	0.664	2.0	1999 MN
1998 FW4	2013 Sep 27	0.0075	19.0	680	3.95	2.498	0.729	3.6	1998 FW4
1998 WT24	2015 Dec 11	0.0277	17.7	1250	0.61	0.718	0.418	7.4	1998 WT24
1999 VP11	2017 Oct 22	0.0151	18.6	820	1.13	1.084	0.584	17.3	1999 VP11
4660 Nereus	2021 Dec 11	0.0263	18.3	950	1.82	1.489	0.360	1.4	4660 Nereus
7482 1994 PC1	2022 Jan 18	0.0132	16.8	1900	1.56	1.346	0.328	33.5	7482 1994 PC1
7335 1989 JA	2022 May 27	0.0269	16.5	2000	2.35	1.770	0.484	15.2	7335 1989 JA
1998 HH49	2023 Oct 16	0.0060	21.5	220	1.93	1.551	0.502	8.4	1998 HH49
2000 GE2	2024 Oct 2	0.0131	20.2	390	2.02	1.596	0.557	2.2	2000 GE2
1997 NC1	2026 Jun 27	0.0171	18.4	900	0.81	0.866	0.208	16.7	1997 NC1
1999 AN10	2027 Aug 7	0.0026	18.0	1100	1.76	1.459	0.562	39.9	1999 AN10
2000 SG344	2028 May 7	0.0200	24.6	Unknown	0.97	0.980	0.067	0.1	2000 SG344
1997 XF11	2028 Oct 26	0.0064	16.8	1900	1.73	1.442	0.484	4.1	1997 XF11
2000 SG344	2029 Feb 16	0.0530	24.6	Unknown	0.97	0.980	0.067	0.1	2000 SG344
2000 SG344	2029 Jul 28	0.0340	24.6	Unknown	0.97	0.980	0.067	0.1	2000 SG344
2000 SG344	2029 Nov 21	0.0450	24.6	Unknown	0.97	0.980	0.067	0.1	2000 SG344
2000 SG344	2030 Sep 22	0.0340	24.6	Unknown	0.97	0.980	0.067	0.1	2000 SG344
1994 WR12	2030 Nov 26	0.0180	22.2	160	0.65	0.754	0.405	7.1	1994 WR12
1998 BB10	2033 Jul 22	0.0269	20.5	340	1.43	1.272	0.425	11.5	1998 BB10
2000 QK130	2036 Mar 15	0.0116	21.1	260	1.28	1,181	0.262	4.7	2000 QK130
1999 KW4	2036 May 25	0.0154	16.6	2000	0.51	0.642	0.688	38.9	1999 KW4
1997 QK1	2039 Jul 14	0.0165	20.1	410	4.67	2.793	0.642	2.9	1997 QK1
1998 SH36	2040 Oct 12	0.0130	20.6	330	1.13	1.088	0.571	2.1	1998 SH36
1998 WT24	2040 Dec 20	0.0278	17.7	1250	0.61	0.718	0.418	7.4	1998 WT24
1998 VD35	2042 May 11	0.0163	20.3	370	1.96	1.565	0.477	7.0	1998 VD35
1999 FA	2046 Mar 5	0.0199	20.6	330	1.12	1.078	0.133	12.0	1999 FA
4769 Castalia	2046 Aug 26	0.0251	16.9	1800 x 800	1.10	1.063	0.483	8.9	4769 Castalia
1862 Apollo	2046 Nov 13	0.0353	16.3	1600	1.81	1.471	0.560	6.4	1862 Apollo
1999 DB7	2048 Feb 28	0.0098	19.9	450	1.32	1.206	0.195	10.8	1999 DB7
1999 AN10	2049 Aug 7	0.0148	18.0	1100	1.76	1.459	0.562	39.9	1999 AN10
4581 Asclepius	2051 Mar 24	0.0122	20.5	340	1.03	1.022	0.357	4.9	4581 Asclepius
2000 TU28	2051 Apr 12	0.0192	21.0	270	1.11	1.074	0.183	15.6	2000 TU28
1620 Geographos	2051 Aug 23	0.0479	15.6	2000	1.39	1.246	0.335	13.3	1620 Geographos
1988 TA	2053 Oct 1	0.0088	20.8	300	1.91	1.541	0.479	2.5	1988 TA
1998 WT24	2054 Dec 19	0.0141	17.7	1250	0.61	0.718	0.418	7.4	1998 WT24
2000 RS11	2056 Mar 14	0.0174	18.9	720	1.45	1.282	0.321	17.1	2000 RS11
1998 SH36	2057 Oct 12	0.0119	20.6	330	1.13	1.088	0.571	2.1	1998 SH36
4660 Nereus	2060 Feb 14	0.0080	18.3	940	1.82	1.489	0.360	1.4	4660 Nereus
1999 RQ36	2060 Sep 22	0.0055	20.9	280	1.20	1.129	0.205	6.0	1999 RQ36
2000 QK130	2067 Mar 17	0.0163	21.1	260	1.28	1,181	0.262	4.7	2000 QK130
2340 Hathor	2069 Oct 21	0.0066	20.3	370	0.78	0.844	0.450	5.8	2340 Hathor
4179 Toutatis	2069 Nov	0.0199	15.3	4600 x 2400	3.98	2.511	0.634	0.5	4179 Toutatis
4660 Nereus	2071 Feb 4	0.0157	18.3	940	1.82	1.489	0.360	1.4	4660 Nereus
1999 KW4	2071 May 26	0.0171	16.6	2000	0.51	0.642	0.688	38.9	1999 KW4
2000 DO1	2075 Mar 10	0.0182	20.4	360	1.70	1.427	0.681	3.4	2000 DO1
1999 JU3	2076 Dec 8	0.0171	19.2	620	1.30	1.189	0.190	5.9	1999 JU3
1998 OR2	2079 Apr 16	0.0119	16.2	2000	3.70	2.391	0.566	5.9	1998 OR2
2000 UG11	2083 Nov 9	0.0180	20.4	360	2.67	1.923	0.570	8.9	2000 UG11
1999 SO5	2086 Apr 6	0.0191	21.0	270	1.13	1.085	0.065	13.4	1999 SO5
2340 Hathor	2086 Oct 21	0.0059	20.3	370	0.78	0.844	0.450	5.8	2340 Hathor
1999 VP11	2086 Oct 22	0.0060	18.6	820	1.13	1.084	0.584	17.3	1999 VP11
1566 Icarus	2090 Jun 14	0.0357	16.4	1400	1.12	1.078	0.8268	22.9	1566 Icarus
1999 MN	2092 Jul 11	0.0187	21.6	200	0.55	0.674	0.664	2.0	1999 MN
1989 UQ	2093 Aug 13	0.0160	19.3	600	0.88	0.915	0.265	1.3	1989 UQ
2000 WO107	2093 Dec 1	0.0127	19.5	540	0.87	0.911	0.781	7.8	2000 WO107
3200 Phaethon	2093 Dec 14	0.0194	14.6	5000	1.43	1.271	0.890	22.1	3200 Phaethon
1998 SC15	2095 Apr 9	0.0088	19.4	570	1.44	1.274	0.415	16.1	1998 SC15
1997 XF11	2095 Oct 26	0.0193	16.8	1900	1.73	1.442	0.484	4.1	1997 XF11
1998 WT24	2099 Dec 18	0.0126	17.7	1250	0.61	0.718	0.418	7.4	1998 WT24
433 Eros	2012 Jan 31	0.1790	11.2	33000 x 13000	1.76	1.458	0.223	10.8	433 Eros

Some Near Earth Asteroids. Athens:Semimajor axis less than 1AU and perhelion distances greater than 0.983 AU.
Apollos: Semimajor axis greater than 1.0 AU and distances less than 1.017AU.
Amors: perihelion distances betweeen 1.017 and 1.3 AU.
Trogans: Located near Jupiter's Lagrange point (60 degrees ahead or behind Jupiter in its orbit, several Hundred are known. It is thought there maybe thousands.

There are a few Asteroids Classed as Centaurs in the outer solar system: 2060 Chiron orbits btween Saturn and Uranus. 5335 Damocles ranges from near Mars to beyond Uranus 5145 Pholus orbit is from Saturn to Neptune. These Orbits that cross these planets are unstable. There is a good chance that they will be permutated in the future. The composition of these objects is probably more like Kuiper belt objects. But now Chiron is classed as a comet.

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