15th Largest Asteroid, 324 Bamberga

324 Bamberga is one of the largest main-belt asteroids and the 15th largest asteroids currently known.

Discovery

Bamberga was discovered by Johann Palisa on February 25, 1892 in Vienna.

Bamberga was the last asteroid which is ever easily visible with binoculars to be discovered.

Naming

Bamberga the asteroid was named after Bamberg, a city in Bavaria, Germany, located in Upper Franconia on the river Regnitz close to its confluence with the river Main.

Bamberg was one of the few cities in Germany not destroyed by World War II bombing because of a nearby artillery factory that prevented planes from getting near to it.

Stats

Diameter (mean): 229 km
Aphelion: 3.591 AU
Perihelion: 1.781 AU
Semi-major axis: 2.686 AU
Orbital Period: 4.40 years
Rotation period: 29.43 hrs
Date discovered: 1892.2.25
Class: C
Type: Main-belt Asteroid
(data from JPL Small-Body Database)

Orbit

Bamberga's 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 1991 and the next in 2013, when attaining magnitude 8.1 on Sept. 13th.

Bamberga's brightness at these rare near-perihelion oppositions makes it 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.

Bamberga has an unusually long rotation period (29.43 hrs) among the large asteroids. Its spectral class is intermediate between the C-type and P-type asteroids.

Star Occultation

An occultation of a star (HIP 59807) by Bamberga was observed on on 20 April 2007. Results from the occultation agrees well with the expected diameter 229 km.