Discovery[1] | |
---|---|
Discovered by | J. C. Watson |
Discovery site | Ann Arbor |
Discovery date | 28 September 1876 |
Designations | |
(168) Sibylla | |
Pronunciation | /sɪˈbɪlə/[2] |
Named after | Sibyls |
A876 SA; 1911 HF; 1949 MO | |
main-belt | |
Adjectives | Sibyllian /sɪˈbɪliən/ |
Orbital characteristics[3][4] | |
Epoch 31 July 2016 (JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 136.01 yr (49676 d) |
Aphelion | 3.6215 AU (541.77 Gm) |
Perihelion | 3.1417 AU (469.99 Gm) |
3.3816 AU (505.88 Gm) | |
Eccentricity | 0.070943 |
6.22 yr (2271.4 d) | |
Average orbital speed | 16.19 km/s |
171.517° | |
0° 9m 30.564s / day | |
Inclination | 4.6617° |
205.959° | |
173.920° | |
Physical characteristics | |
Dimensions | 148.39±4.0 km[3] 149.06 ± 4.29 km[5] |
Mass | (3.92 ± 1.80) × 1018 kg[5] |
Mean density | 2.26 ± 1.05 g/cm3[5] |
47.009 h (1.9587 d) | |
23.82 hours[6] | |
0.0535±0.003 | |
C | |
7.94 | |
168 Sibylla is a large main-belt asteroid, discovered by Canadian-American astronomer J. C. Watson on September 28, 1876. It was most likely named for the Sibyls, referring to the Ancient Greek female oracles.[7] Based upon its spectrum this object is classified as a C-type asteroid, which indicates it is very dark and composed of primitive carbonaceous materials. 168 Sibylla is a Cybele asteroid, orbiting beyond most of the main-belt asteroids.
Photometric observations of this asteroid made at the Torino Observatory in Italy during 1990–1991 were used to determine a synodic rotation period of 23.82 ± 0.004 hours.[6] The shape of this slowly rotating object appears to resemble an oblate spheroid.[8]
JPL
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