122 Gerda is a fairly large outer main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on July 31, 1872, and named after Gerðr, the wife of the god Freyr in Norse mythology. Based upon its spectrum, this is classified as an S-type asteroid.[4] It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter.[5]
_Gerda.png) 3D convex shape model of 122 Gerda | |
| Discovery | |
|---|---|
| Discovered by | Christian Heinrich Friedrich Peters |
| Discovery date | 31 July 1872 |
| Designations | |
| (122) Gerda | |
| Pronunciation | /ˈɡɜːrdə/[1] |
| A872 OA; 1948 TQ1 | |
| Main belt | |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 143.71 yr (52491 d) |
| Aphelion | 3.32884 AU (497.987 Gm) |
| Perihelion | 3.11932 AU (466.644 Gm) |
| 3.22408 AU (482.316 Gm) | |
| Eccentricity | 0.032493 |
| 5.79 yr (2114.5 d) | |
Average orbital speed | 16.59 km/s |
| 163.616° | |
| 0° 10m 12.911s / day | |
| Inclination | 1.64006° |
| 178.139° | |
| 321.617° | |
| Earth MOID | 2.13107 AU (318.804 Gm) |
| Jupiter MOID | 1.66324 AU (248.817 Gm) |
| TJupiter | 3.187 |
| Physical characteristics | |
| Dimensions | 81.69±1.9 km |
| Mass | 5.7×1017 kg |
Equatorial surface gravity | 0.0228 m/s2 |
Equatorial escape velocity | 0.0432 km/s |
| 10.685 h (0.4452 d)[2] 10.687 ± 0.001 h[3] | |
| 0.1883±0.009 | |
| Temperature | ~155 K |
| S[4] | |
| 7.87 | |
Photometric observations of this asteroid in 2007 were used to produce a light curve that showed that Gerda rotates every 10.687 ± 0.001 hours and varied in brightness by 0.16 in magnitude.[3] In 2009, observations at the Organ Mesa Observatory in Las Cruces, New Mexico generated a light curve with a period of 10.712 ± 0.01 hours with a brightness variation of 0.11 ± 0.01 magnitudes. This is compatible with previous studies.[6]
See also
editReferences
edit- ^ Noah Webster (1884) A Practical Dictionary of the English Language
- ^ a b Yeomans, Donald K., "122 Gerda", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
- ^ a b Buchheim, Robert K. (March 2007), "Lightcurves for 122 Gerda, 217 Eudora, 631 Phillipina 670 Ottegebe, and 972 Cohnia", The Minor Planet Bulletin, vol. 34, no. 1, pp. 13–14, Bibcode:2007MPBu...34...13B.
- ^ a b Devogèle, M.; Tanga, P.; Cellino, A.; Bendjoya, Ph.; Rivet, J. -P.; Surdej, J.; Vernet, D.; Sunshine, J. M.; Bus, S. J.; Abe, L.; Bagnulo, S.; Borisov, G.; Campins, H.; Carry, B.; Licandro, J.; McLean, W.; Pinilla-Alonso, N. (April 2018), "New polarimetric and spectroscopic evidence of anomalous enrichment in spinel-bearing calcium-aluminium-rich inclusions among L-type asteroids", Icarus, 304: 31–57, arXiv:1802.06975, Bibcode:2018Icar..304...31D, doi:10.1016/j.icarus.2017.12.026
- ^ McDonald, Sophia Levy (June 1948), "General perturbations and mean elements, with representations of 35 minor planets of the Hecuba group", Astronomical Journal, 53: 199, Bibcode:1948AJ.....53..199M, doi:10.1086/106097.
- ^ Pilcher, Frederick (October 2009), "New Lightcurves of 8 Flora, 13 Egeria, 14 Irene, 25 Phocaea 40 Harmonia, 74 Galatea, and 122 Gerda", The Minor Planet Bulletin, vol. 36, no. 4, pp. 133–136, Bibcode:2009MPBu...36..133P.
External links
edit- 122 Gerda at AstDyS-2, Asteroids—Dynamic Site
- 122 Gerda at the JPL Small-Body Database
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