(12755) Balmer Main-belt Asteroid
Discovered on 20 July 1993 by E. W. Elst at La Silla.
Johann J. Balmer (1825-1898) was a Swiss high-school teacher who examined the four visible lines in the spectrum of the hydrogen atom. By playing around with the numbers of their wavelengths, he finally put all four wavelengths into one equation, i.e., Balmer's formula.Naming citation (20041126/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Balmer is today
Seen from above the solar system on 2026-10-14: Balmer is 2.75 au from the Sun and 2.40 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 12755 |
| Provisional designation | 1993 OS10 |
| Orbit class | Main-belt Asteroid |
| Diameter | 9.36 km (#5,512 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0800 |
| Rotation period | 6.59 hours |
| Absolute magnitude (H) | 13.95 |
| Orbital period | 4.50 years |
| Semi-major axis | 2.72 au |
| Perihelion – aphelion | 2.66 – 2.79 au |
| Eccentricity | 0.0225 |
| Inclination | 4.03° |
| Closest distance between its orbit and Earth's (MOID) | 1.65 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Johann
- (1651) Behrens
- (5195) Kaendler
- (6734) Benzenberg
- (7449) Dollen
- (8158) Herder
- (8203) Jogolehmann
- (8368) Lamont
- (8583) Froberger
- (9052) Uhland
- (9134) Encke
- (10749) Musaus
- (11673) Baur
All asteroids named after someone called Johann
Also discovered on 20 July 1993
- (6977) Jaucourt
- (7478) Hasse
- (8096) Emilezola
- (8190) Bouguer
- (8191) Mersenne
- (9376) Thionville
- (10136) Gauguin
- (11571) Daens
- (11943) Davidhartley
- (11944) Shaftesbury
- (12352) Jepejacobsen
- (12353) Marquez