122 Gerda

Gerda (minor planet designation: 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]

122 Gerda
Discovery
Discovered byChristian Heinrich Friedrich Peters
Discovery date31 July 1872
Designations
(122) Gerda
Pronunciation/ˈɡɜːrdə/[1]
 
Main belt
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc143.71 yr (52491 d)
Aphelion3.32884 AU (497.987 Gm)
Perihelion3.11932 AU (466.644 Gm)
3.22408 AU (482.316 Gm)
Eccentricity0.032493
5.79 yr (2114.5 d)
16.59 km/s
163.616°
0° 10m 12.911s / day
Inclination1.64006°
178.139°
321.617°
Earth MOID2.13107 AU (318.804 Gm)
Jupiter MOID1.66324 AU (248.817 Gm)
TJupiter3.187
Physical characteristics
Dimensions81.69±1.9 km
Mass5.7×1017 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

    References
    1. Noah Webster (1884) A Practical Dictionary of the English Language
    2. Yeomans, Donald K., "122 Gerda", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
    3. 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. 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
    5. 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.
    6. 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.


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