.gif) | |
| Discovery | |
|---|---|
| Discovered by | C. H. F. Peters |
| Discovery site | Litchfield Obs. |
| Discovery date | 7 July 1867 |
| Designations | |
| (92) Undina | |
| Pronunciation | /ʌnˈdaɪnə/[1] |
| Main belt | |
| Adjectives | Undinian/ʌnˈdɪniən/[2] |
| Orbital characteristics[3] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 145.11 yr (53001 d) |
| Aphelion | 3.51946 AU (526.504 Gm) |
| Perihelion | 2.85654 AU (427.332 Gm) |
| 3.18800 AU (476.918 Gm) | |
| Eccentricity | 0.10397 |
| 5.69yr (2079.1d) | |
| 6.12456° | |
| 0° 10m 23.347s / day | |
| Inclination | 9.92900° |
| 101.588° | |
| 239.494° | |
| Physical characteristics | |
| 126.42±3.4 km[3] 124.44 ± 3.25 km[4] | |
| Mass | (4.43 ± 0.25) × 1018 kg[4] |
Meandensity | 4.39 ± 0.42 g/cm3[4] |
| 15.941 h (0.6642 d) | |
| 0.2509±0.014[3] 0.251[5] | |
| M | |
| 6.61 | |
92 Undina (from LatinUndīna) is a largemain beltasteroid. The asteroid was discovered byChristian Peters on 7 July 1867 from theHamilton College Observatory.[6] It is named for the eponymous heroine ofUndine, a popularnovella byFriedrich de la Motte Fouqué.
This minor planet is orbiting at a distance of around 3 AU from the Sun, which is known for a concentration ofTholenM-type asteroids. Indeed, 92 Undina has an unusually high albedo of 0.25 and an M-type spectrum, or Xc-type on the Bus taxonomy.[7] However, it displays absorption features at awavelength of 3 μm, which is usually indicative of hydrated silicates on the surface.[8] There is a faint band in the region of 9 μm that is typically attributed to a form oforthopyroxene having low levels of calcium and iron. The spectrum of 92 Undina closely resembles powdered material from theEsquel meteorite, although with a higher albedo.[7]
Observations performed at the Palmer Divide Observatory inColorado Springs, Colorado during 2007 produced alight curve with a period of 15.941 ± 0.002 hours with a brightness range of 0.20 ± 0.02 inmagnitude. This matches a 15.94-hour period reported in 1979.[9] Attempts in 2014 to model the spin axis and shape based on light curve information proved inconclusive, but did indicate that "the pole latitude is not far removed from the ecliptic plane and rotation is probably retrograde".[10]
