Astronomy:122 Gerda
_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 | |
| Minor planet category | Main belt |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 143.71 yr (52491 d) |
| |{{{apsis}}}|helion}} | 3.32884 astronomical unit|AU (497.987 Gm) |
| |{{{apsis}}}|helion}} | 3.11932 AU (466.644 Gm) |
| 3.22408 AU (482.316 Gm) | |
| Eccentricity | 0.032493 |
| Orbital period | 5.79 yr (2114.5 d) |
| Average Orbital speed | 16.59 km/s |
| Mean anomaly | 163.616° |
| Mean motion | 0° 10m 12.911s / day |
| Inclination | 1.64006° |
| Longitude of ascending node | 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 |
| Rotation period | 10.685 h (0.4452 d)[2] 10.687 ± 0.001 h[3] |
| Geometric albedo | 0.1883±0.009 |
| Physics | ~155 K |
| S[4] | |
| Absolute magnitude (H) | 7.87 |
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. It was named after Gerðr, the wife of the god Freyr in Norse mythology.
This asteroid is orbiting the Sun at a distance of 3.22 astronomical unit|AU with a low eccentricity of 0.03 and an orbital period of 5.79 years. The orbital plane is inclined at an angle of 1.64° to the plane of the ecliptic. This body is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter.[5]
Based upon its spectrum, this is classified as a stony S-type asteroid.[4] It has a measured diameter of 82 km.[2] 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
References
- ↑ Noah Webster (1884) A Practical Dictionary of the English Language
- ↑ 2.0 2.1 2.2 Yeomans, Donald K., "122 Gerda", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=122, retrieved 12 May 2016.
- ↑ 3.0 3.1 Buchheim, Robert K. (March 2007), "Lightcurves for 122 Gerda, 217 Eudora, 631 Phillipina 670 Ottegebe, and 972 Cohnia", The Minor Planet Bulletin 34 (1): pp. 13–14, Bibcode: 2007MPBu...34...13B.
- ↑ 4.0 4.1 Devogèle, M.; Tanga, P.; Cellino, A.; Bendjoya, Ph.; Rivet, J. -P.; Surdej, J.; Vernet, D.; Sunshine, J. M. et al. (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, doi:10.1016/j.icarus.2017.12.026, Bibcode: 2018Icar..304...31D
- ↑ McDonald, Sophia Levy (June 1948), "General perturbations and mean elements, with representations of 35 minor planets of the Hecuba group", Astronomical Journal 53: 199, doi:10.1086/106097, Bibcode: 1948AJ.....53..199M.
- ↑ 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 36 (4): pp. 133–136, Bibcode: 2009MPBu...36..133P.
External links
- 122 Gerda at AstDyS-2, Asteroids—Dynamic Site
- 122 Gerda at the JPL Small-Body Database
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