168 Sibylla

168 Sibylla

Orbital diagram
Discovery[1]
Discovered by	J. C. Watson
Discovery site	Ann Arbor
Discovery date	28 September 1876
Designations
MPC designation	(168) Sibylla
Pronunciation	/sɪˈbɪlə/[2]
Named after	Sibyls
Alternative designations	A876 SA; 1911 HF; 1949 MO
Minor planet category	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)
Semi-major axis	3.3816 AU (505.88 Gm)
Eccentricity	0.070943
Orbital period (sidereal)	6.22 yr (2271.4 d)
Average orbital speed	16.19 km/s
Mean anomaly	171.517°
Mean motion	0° 9^m 30.564^s / day
Inclination	4.6617°
Longitude of ascending node	205.959°
Argument of perihelion	173.920°
Physical characteristics
Dimensions	148.39±4.0 km[3] 149.06 ± 4.29 km[5]
Mass	(3.92 ± 1.80) × 10^18 kg[5]
Mean density	2.26 ± 1.05 g/cm^3[5]
Synodic rotation period	47.009 h (1.9587 d)
Sidereal rotation period	23.82 hours[6]
Geometric albedo	0.0535±0.003
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. 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]

References

1. "Discovery Circumstances: Numbered Minor Planets (1)-(5000)". Retrieved 14 August 2012.
2. "Sibylla". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
3. Yeomans, Donald K., "168 Sibylla", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
4. "The Asteroid Orbital Elements Database". astorb. Lowell Observatory. Retrieved 14 August 2012.
5. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73 (1): 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009, S2CID 119226456. See Table 1.
6. di Martino, M.; et al. (February 1994), "Lightcurves and rotational periods of nine main belt asteroids", Icarus, 107 (2): 269–275, Bibcode:1994Icar..107..269D, doi:10.1006/icar.1994.1022.
7. Schmadel, Lutz (2003), Dictionary of Minor Planet Names, Physics and astronomy online library, vol. 1, Springer Science & Business Media, p. 30, ISBN 9783540002383.
8. Wang, Xiaobin; et al. (January 2016), "Studies for slowly rotating asteroids (168) Sibylla and (346) Hermentaria", Asteroids: New Observations, New Models, Proceedings of the International Astronomical Union, IAU Symposium, vol. 318, pp. 185–192, Bibcode:2016IAUS..318..185W, doi:10.1017/S1743921315008777.

External links

• 168 Sibylla at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 168 Sibylla at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters