| Minorplanet: | yes |
| Background: |
|
| 324 Bamberga | |
| Discovered: | 25 February 1892 |
| Mpc Name: | (324) Bamberga |
| Adjective: | Bambergian |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.68232AU |
| Perihelion: | 1.77023AU |
| Aphelion: | 3.59442abbr=onNaNabbr=on |
| Eccentricity: | 0.34004 |
| Period: | 4.39 yr (1604.6 d) |
| Inclination: | 11.1011° |
| Asc Node: | 327.883° |
| Arg Peri: | 44.2409° |
| Dimensions: | c/a = |
| Mean Diameter: | [1] 234.67 ± 7.80 km 229.4 ± 7.4 km [2] |
| Mass: | [3] |
| Density: | |
| Rotation: | 1.226 d[4] 29.43abbr=onNaNabbr=on[5] |
| Spectral Type: | C-type asteroid[6] |
| Abs Magnitude: | 6.82 |
| Albedo: | 0.060 (calculated) |
| Mean Motion: | / day |
| Observation Arc: | 124.08 yr (45321 d) |
| Uncertainty: | 0 |
324 Bamberga is one of the largest asteroids in the asteroid belt. It was discovered by Johann Palisa on 25 February 1892 in Vienna. It is one of the top-20 largest asteroids in the asteroid belt. Apart from the near-Earth asteroid Eros, it was the last asteroid which is ever easily visible with binoculars to be discovered.
Overall Bamberga is the tenth-brightest main-belt asteroid after, in order, Vesta, Pallas, Ceres, Iris, Hebe, Juno, Melpomene, Eunomia and Flora. Its high eccentricity (for comparison 36% higher than that of Pluto), though, means that at most oppositions other asteroids reach higher magnitudes.
Although its very high orbital eccentricity means its opposition magnitude varies greatly, at a rare opposition near perihelion Bamberga can reach a magnitude of +8.0,[7] which is as bright as Saturn's moon Titan. Such near-perihelion oppositions occur on a regular cycle every twenty-two years, with the last occurring in 2013 and the next in 2035, when attaining magnitude 8.1 on 13 September. Its brightness at these rare near-perihelion oppositions makes Bamberga the brightest C-type asteroid, roughly one magnitude brighter than 10 Hygiea's maximum brightness of around +9.1. At such an opposition Bamberga can in fact be closer to Earth than any main-belt asteroid with magnitude above +9.5, getting as close as 0.78 AU. For comparison, 7 Iris never comes closer than 0.85 AU and 4 Vesta never closer than 1.13 AU (when it becomes visible to the naked eye in a light pollution-free sky).
The 29-hour rotation period is unusually long for an asteroid more than 150 km in diameter. Its spectral class is intermediate between the C-type and P-type asteroids.
10μ radiometric data collected from Kitt Peak in 1975 gave a diameter estimate of 255 km. An occultation of Bamberga was observed on 8 December 1987, and gave a diameter of about 228 km, in agreement with IRAS results. In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.