76 Freia
Discovery | |
---|---|
Discovered by | Heinrich d'Arrest |
Discovery date | October 21, 1862 |
Designations | |
MPC designation | (76) Freia |
Pronunciation | /ˈfreɪ.ə/[2] |
Named after | Freyja |
Minor planet category | Outer main belt[1] (Cybele) |
Adjectives | Freian |
Orbital characteristics | |
Epoch December 31, 2006 (JD 2454100.5) | |
Aphelion | 594.715 Gm (3.975 AU) |
Perihelion | 427.898 Gm (2.860 AU) |
511.306 Gm (3.418 AU) | |
Eccentricity | 0.163 |
2307.979 d (6.32 a) | |
Average orbital speed | 16.00 km/s |
299.268° | |
Inclination | 2.116° |
204.535° | |
254.070° | |
Physical characteristics | |
Dimensions | 183.7±4 km[1] |
Mass | (1.97 ± 4.20) × 1018 kg[3] |
Mean density | 0.79 ± 1.69[3] g/cm3 |
Equatorial surface gravity | 0.0513 m/s2 |
Equatorial escape velocity | 0.0971 km/s |
Synodic rotation period | 9.968240±0.000009 h[4] |
0.036 [5] | |
CP | |
Absolute magnitude (H) | 7.90 |
Freia (minor planet designation: 76 Freia) is a very large main-belt asteroid. It orbits in the outer part of the asteroid belt and is classified as a Cybele asteroid.[6] Its composition is very primitive and it is extremely dark in color. Freia was discovered by the astronomer Heinrich d'Arrest on October 21, 1862, in Copenhagen, Denmark. It was his first and only asteroid discovery. It is named after the goddess Freyja in Norse mythology.
The sidereal orbital period of this asteroid is commensurable with that of Jupiter, which made it useful for ground-based mass estimates of the giant planet.[7] A shape model for the asteroid was published by Stephens and Warner (2008), based upon lightcurve data. This yielded a sidereal rotation period of 9.968240±0.000009 h. They found two possible solutions for the spin axis, with the preferred solution in ecliptic coordinates being (λ, β) = (139°±5°, 25°±5°).[4]
References[]
- ^ a b "JPL Small-Body Database Browser: 76 Freia" (2008-03-04 last obs). Retrieved 5 September 2010.
- ^ "Freya". Lexico UK English Dictionary. Oxford University Press. n.d.
- ^ a b Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
- ^ a b Stephens, Robert D.; Warner, Brian D. (June 2008), "A Preliminary Shape and Spin Axis Model for 76 Freia", The Minor Planet Bulletin, 35 (2): 84−85, Bibcode:2008MPBu...35...84S.
- ^ Asteroid Data Sets Archived 2009-12-17 at the Wayback Machine
- ^ De Prá, M. N.; et al. (September 2018), "PRIMASS visits Hilda and Cybele groups", Icarus, 311: 35–51, arXiv:1711.02071, Bibcode:2018Icar..311...35D, doi:10.1016/j.icarus.2017.11.012.
- ^ Klepczynski, W. J.; et al. (November 1971), "The Mass of Jupiter from the Motion of (76) Freia", Astronomical Journal, 76: 939, Bibcode:1971AJ.....76..939K, doi:10.1086/111204.
External links[]
- 76 Freia at AstDyS-2, Asteroids—Dynamic Site
- 76 Freia at the JPL Small-Body Database
- Minor planet object articles (numbered)
- Cybele asteroids
- Discoveries by Heinrich Louis d'Arrest
- Minor planets named from Norse mythology
- Named minor planets
- P-type asteroids (Tholen)
- X-type asteroids (SMASS)
- Astronomical objects discovered in 1862
- C-type main-belt-asteroid stubs