77 Frigga
Main-belt asteroid
From Wikipedia, the free encyclopedia
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.
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| Discovery | |
|---|---|
| Discovered by | Christian Heinrich Friedrich Peters |
| Discovery date | November 12, 1862 |
| Designations | |
| (77) Frigga | |
| Pronunciation | /ˈfrɪɡə/[1] |
Named after | Frigg |
| Main belt | |
| Adjectives | [citation needed] |
| Orbital characteristics | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 452.196 million km (3.023 AU) |
| Perihelion | 346.228 million km (2.314 AU) |
| 399.212 million km (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° | |
| 61.419° | |
| Physical characteristics | |
| Dimensions | 60.0 × 74.0 km[2] |
| 61.390 ± 0.177 km[3] | |
| Mass | (4.16 ± 2.30/1)×1017 kg[4] |
Mean density | 3.434 ± 1.901/0.827 g/cm3[4] |
Equatorial surface gravity | 0.0074 m/s² |
Equatorial escape velocity | 0.0301 km/s |
| 9.0032 hr[3] | |
| 0.177 ± 0.025[3] 0.144[5] | |
| M | |
| 8.65[3] | |
Frigga has been studied by radar.[6] The spectra of this asteroid displays a feature at a wavelength of 3 μm, indicating the presence of hydrated minerals on the surface.[7] The near infrared spectrum is reddish and shows no spectral absorption features. Potential analogs of this spectrum include enstatite chondrites and nickel-iron meteorites.[8]
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 60.0 × 74.0 kilometres at PA -14degrees.[2]
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