168 Sibylla

168 Sibylla

Discovery[1]
Discovered by	J. C. Watson
Discovery site	Ann Arbor
Discovery date	September 28, 1876
Orbital characteristics[2][3]
Aphelion	3.601 AU
Perihelion	3.154 AU
Semi-major axis	3.377 AU
Eccentricity	0.066
Orbital period	6.21 years
Average orbital speed	16.19 km/s
Mean anomaly	261.860°
Inclination	4.63°
Longitude of ascending node	206.469°
Argument of perihelion	168.166
Physical characteristics
Dimensions	149.06 ± 4.29[4] km
Mass	(3.92 ± 1.80) × 10^18 kg[4]
Mean density	2.26 ± 1.05[4] g/cm^3
Sidereal rotation period	23.82[5] hours
Albedo	0.054
Spectral type	C
Absolute magnitude (H)	7.94

168 Sibylla is a large main-belt asteroid, discovered by Canadian-American astronomer J. C. Watson on September 28, 1876. 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.^[5]

References

1. "Discovery Circumstances: Numbered Minor Planets (1)-(5000)". Retrieved August 14, 2012.
2. Yeomans, Donald K., "168 Sibylla", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-25.
3. "The Asteroid Orbital Elements Database". Retrieved August 14, 2012.
4. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
5. di Martino, M.; et al. (February 1994), "Lightcurves and rotational periods of nine main belt asteroids", Icarus 107 (2), pp. 269–275, Bibcode:1994Icar..107..269D, doi:10.1006/icar.1994.1022.

External links

• 168 Sibylla at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters