_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 | |
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]
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]
- ^ Noah Webster (1884) A Practical Dictionary of the English Language
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