122 Gerda
Main-belt asteroid
From Wikipedia, the free encyclopedia
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.
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3D convex shape model of 122 Gerda | |
| Discovery | |
|---|---|
| Discovered by | Christian Heinrich Friedrich Peters |
| Discovery date | 31 July 1872 |
| Designations | |
| (122) Gerda | |
| Pronunciation | /ËÉ¡ÉËrdÉ/[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 | 5.7Ã1017 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 | |
This asteroid is orbiting the Sun at a distance of 3.22 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]
