77 Frigga
Frigga (minor planet designation: 77 Frigga) is a large, M-type, possibly metallic main-belt asteroid. It was discovered by the German-American astronomer C. H. F. Peters on November 12, 1862. The object is named after Frigg, the Norse goddess. The asteroid is orbiting the Sun with a period of 4.36 years and completes a rotation on its axis every nine hours.
| Discovery | |
|---|---|
| Discovered by | Christian Heinrich Friedrich Peters |
| Discovery date | November 12, 1862 |
| Designations | |
| (77) Frigga | |
| Pronunciation | /ˈfrɪɡə/[1] |
Named after | Frigg |
| Main belt | |
| Adjectives | |
| Orbital characteristics | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 452.196 Gm (3.023 AU) |
| Perihelion | 346.228 Gm (2.314 AU) |
Semi-major axis | 399.212 Gm (2.669 AU) |
| Eccentricity | 0.133 |
| 1592.266 d (4.36 a) | |
Average orbital speed | 18.15 km/s |
| 346.682° | |
| Inclination | 2.433° |
| 1.332° | |
Argument of perihelion | 61.419° |
| Physical characteristics | |
| Dimensions | 69.2 km[2] |
| Mass | (1.74 ± 0.68) × 1018 kg[3] |
Mean density | 11.05 ± 4.34[3] g/cm3 |
Equatorial surface gravity | 0.0193 m/s² |
Equatorial escape velocity | 0.0366 km/s |
| 9.0 hr[2] | |
| 0.144[2][4] | |
Spectral type | M |
| 8.52[2] | |
Frigga has been studied by radar.[5] The spectra of this asteroid displays a feature at a wavelength of 3 μm, indicating the presence of hydrated minerals on the surface.[6] The near infrared spectrum is reddish and shows no spectral absorption features. Potential analogs of this spectrum include enstatite chondrites and nickel-iron meteorites.[7]
Since 1999 there have been four stellar occultations by the asteroid. The first three were single chord observations, and the fourth was a 3-chord observation, and a miss. The best fit ellipse measures 60.0x74.0 kilometres at PA -14degrees.[8]
References
- Upton, Clive; Kretzschmar, William A., Jr. (2017). The Routledge Dictionary of Pronunciation for Current English (2nd ed.). Routledge. p. 519. ISBN 978-1-138-12566-7.
- "JPL Small-Body Database Browser: 77 Frigga" (2012-01-04 last obs). Jet Propulsion Laboratory. Retrieved 27 January 2012.
- 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.
- Asteroid Data Sets Archived 2009-12-17 at the Wayback Machine
- "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 27 January 2012.
- Gil-Hutton, R. (March 2007), "Polarimetry of M-type asteroids", Astronomy and Astrophysics, 464 (3): 1127−1132, Bibcode:2007A&A...464.1127G, doi:10.1051/0004-6361:20066348.
- Takir, D.; et al. (March 2008), "The Near-Infrared Spectroscopy of Two M-Class Main Belt Asteroids, 77 Frigga and 325 Heidelberga", 39th Lunar and Planetary Science Conference, (Lunar and Planetary Science XXXIX), held March 10-14, 2008 in League City, Texas. LPI Contribution No. 1391., p. 1084, Bibcode:2008LPI....39.1084T
- "PDS Asteroid/Dust Subnode". sbn.psi.edu. Archived from the original on 25 April 2018. Retrieved 19 May 2018.
External links
- Lightcurve plot of 77 Frigga, Palmer Divide Observatory, B. D. Warner (2012)
- Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 77 Frigga at AstDyS-2, Asteroids—Dynamic Site
- 77 Frigga at the JPL Small-Body Database