324 Bamberga

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324 Bamberga
Discovery A
Discoverer Johann Palisa
Discovery date February 25, 1892
Alternate
designations B		 none
Category Main belt
Orbital elements C
Epoch 30 January 2005 (JD 2453400.5)
Eccentricity (e) 0.338
Semi-major axis (a) 401.409 Gm (2.683 AU)
Perihelion (q) 265.576 Gm (1.775 AU)
Aphelion (Q) 537.241 Gm (3.591 AU)
Orbital period (P) 1605.397 d (4.4 a)
Mean orbital speed 18.18 km/s
Inclination (i) 11.107°
Longitude of the
ascending node (Ω)		 328.058°
Argument of
perihelion (ω)		 44.062°
Mean anomaly (M) 4.564°
Physical characteristics D
Dimensions 229 km[1]
Mass 1.1×1019 kg[2]
Density 1.8 g/cm³
Surface gravity 0.014 m/s²
Escape velocity 0.23 km/s
Rotation period 1.226 d[3]
Spectral class C-type asteroid[4]
Absolute magnitude 6.82[1]
Albedo (geometric) 0.0628[1]
Mean surface
temperature		 ~172 K
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324 Bamberga (pronounced /bæmˈbɝɡə/ bam-bər'-gə) is the 16th largest asteroid in the Main asteroid belt. It was discovered by Johann Palisa on February 25, 1892 in Vienna, making it one of the last large (diameter over 200 km) asteroids discovered. Apart from the near-earth asteroid Eros, it was the last asteroid which is ever easily visible with binoculars to be discovered.

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[5], 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 1991 and the next in 2013. 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.

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.

It has an unusually long rotation period among the large asteroids. Its spectral class is intermediate between the C-type and P-type asteroids.[4]

An occultation of Bamberga was observed on 8 December 1987, and gave a diameter of about 228 km, in agreement with IRAS results.

[edit] Bamberga in fiction

See Asteroids in fiction.

[edit] References

  1. ^ a b c 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. Retrieved on 2007-03-15.
  2. ^ Pitjeva, E. V. (2005). "High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants" (PDF). Solar System Research 39 (3): 176. doi:10.1007/s11208-005-0033-2. 
  3. ^ 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. Retrieved on 2007-03-15.
  4. ^ a b Neese, C.; Ed. (2005). Asteroid Taxonomy.EAR-A-5-DDR-TAXONOMY-V5.0.. NASA Planetary Data System. Retrieved on 2007-03-15.
  5. ^ Donald H. Menzel and Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets, 2nd edition, Boston, MA: Houghton Mifflin, p. 391. ISBN 0395348358. 
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