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.
Observation
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, 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).
Characteristics
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.
Notes
- Flattening derived from the maximum aspect ratio (c/a): , where (c/a) = 0.96±0.05.
, where (c/a) = 0.96±0.05.
References
- ^ "JPL Small-Body Database Browser: 324 Bamberga". 2008-07-26 last obs. Retrieved 11 May 2016.
- ^ P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
- ^ Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
- ^ Tedesco, E.F.; Noah, P.V.; Noah, M.; Price, S.D. (2004). "IRAS Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0". NASA Planetary Data System. Archived from the original on 19 January 2007. Retrieved 15 March 2007.
- Pitjeva, E. V. (2005). "High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants" (PDF). Solar System Research. 39 (3): 176. Bibcode:2005SoSyR..39..176P. doi:10.1007/s11208-005-0033-2. Archived from the original (PDF) on 31 October 2008.
- Harris, A. W.; Warner, B.D.; Pravec, P., eds. (2006). "Asteroid Lightcurve Derived Data. EAR-A-5-DDR-DERIVED-LIGHTCURVE-V8.0". NASA Planetary Data System. Archived from the original on 28 January 2007. Retrieved 15 March 2007.
- ^ Neese, C., ed. (2005). "Asteroid Taxonomy.EAR-A-5-DDR-TAXONOMY-V5.0". NASA Planetary Data System. Archived from the original on 10 March 2007. Retrieved 15 March 2007.
- Donald H. Menzel & Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd ed.). Boston, MA: Houghton Mifflin. p. 391. ISBN 0-395-34835-8.
- "JPL Small-Body Database Search Engine: diameter > 150 (km) and rot_per > 24 (h)". JPL Solar System Dynamics. Retrieved 6 June 2015.
- Morrison, D.; Chapman, C. R. (March 1976), "Radiometric diameters for an additional 22 asteroids", Astrophysical Journal, vol. 204, pp. 934–939, Bibcode:2008mgm..conf.2594S, doi:10.1142/9789812834300_0469.
- Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference, vol. 19, pp. 405–406, Bibcode:1988LPI....19..405G.
External links
- 324 Bamberga at AstDyS-2, Asteroids—Dynamic Site
- 324 Bamberga at the JPL Small-Body Database
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