| Minorplanet: | yes |
| Background: |
|
| 123 Brunhild | |
| Discovered: | 31 July 1872 |
| Mpc Name: | (123) Brunhild |
| Alt Names: | A872 OB |
| Pronounced: | [1] |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.6971AU |
| Perihelion: | 2.37594AU |
| Aphelion: | 3.0183abbr=onNaNabbr=on |
| Eccentricity: | 0.11907 |
| Period: | 4.43 yr (1617.9 d) |
| Inclination: | 6.4142° |
| Asc Node: | 307.834° |
| Arg Peri: | 125.960° |
| Avg Speed: | 18.08 km/s |
| Dimensions: | 48 km |
| Mass: | 1.2 kg (assumed) |
| Surface Grav: | 0.0134 m/s2 |
| Escape Velocity: | 0.0254 km/s |
| Rotation: | 10.04abbr=onNaNabbr=on |
| Magnitude: | 11.77 to 14.88 |
| Abs Magnitude: | 8.9 |
| Mean Motion: | / day |
| Observation Arc: | 143.71 yr (52490 days) |
| Uncertainty: | 0 |
| Moid: | 1.39621AU |
| Jupiter Moid: | 2.22588AU |
| Tisserand: | 3.350 |
123 Brunhild is a stony S-type main-belt asteroid. It was discovered by German-American astronomer C. H. F. Peters on July 31, 1872, and named after Brünnehilde, a Valkyrie in Norse mythology. Brunhild has been mistaken for the non-existent variable star KN Gem.
In 1983, 123 Brunhild was observed photometrically from the Observatoire de Haute-Provence, producing an irregular light curve that showed eight extremes, including two minima and two maxima that were more accentuated than the others. This curve indicates an irregular shape or possibly areas with higher albedo, with a rotation period of 10.04 ± 0.02 hours and a brightness variation of 0.16 ± 0.01 in magnitude.
Based upon IRAS observations, the estimated diameter of this asteroid is 47.97 ± 2.6 km with a geometric albedo of 0.2134 ± 0.026. A smaller diameter value of 41.33 ± 1.73 km is obtained from the Midcourse Space Experiment observations, with an accordingly higher albedo of 0.2886 ± 0.0247.