.png) A three-dimensional model of 76 Freia based on its light curve. | |
| Discovery | |
|---|---|
| Discovered by | Heinrich d'Arrest |
| Discovery date | October 21, 1862 |
| Designations | |
| MPC designation | (76) Freia |
| Pronunciation | /ˈfreɪ.ə/ |
| Named after | Freyja |
| Minor planet category | Outer main belt (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) |
| Semi-major axis | 511.306 Gm (3.418 AU) |
| Eccentricity | 0.163 |
| Orbital period (sidereal) | 2307.979 d (6.32 a) |
| Average orbital speed | 16.00 km/s |
| Mean anomaly | 299.268° |
| Inclination | 2.116° |
| Longitude of ascending node | 204.535° |
| Argument of perihelion | 254.070° |
| Physical characteristics | |
| Dimensions | 183.7±4 km |
| Mass | (1.97 ± 4.20) × 10 kg |
| Mean density | 0.79 ± 1.69 g/cm |
| Equatorial surface gravity | 0.0513 m/s |
| Equatorial escape velocity | 0.0971 km/s |
| Synodic rotation period | 9.968240±0.000009 h |
| Geometric albedo | 0.036 |
| Spectral type | CP |
| Absolute magnitude (H) | 7.90 |
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. 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. 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°).
References
- "Freya". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 22 March 2020.
- ^ "JPL Small-Body Database Browser: 76 Freia" (2008-03-04 last obs). Retrieved 5 September 2010.
- ^ 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.
- ^ 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, S2CID 119383924.
- 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
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