203 Pompeja

203 Pompeja is a fairly large main-belt asteroid. It was discovered by Christian [Heinrich Friedrich Peters|C. H. F. Peters] on September 25, 1879, in Clinton, [Oneida County, New York|Clinton, New York], and named after Pompeii, the Roman town destroyed in a volcanic eruption in AD 79. This asteroid is orbiting the Sun at a distance of with an eccentricity of 0.06 and a period of. The orbital plane is tilted at an angle of 3.2° to the plane of the ecliptic.
Based upon photometric observations taken during 2011, it has a synodic rotation period of 24.052 ± 0.001 h, with a peak-to-peak amplitude of 0.10 ± 0.01 in magnitude. Because the rotation period nearly matches that of the Earth, it required coordinated observations from multiple observatories at widely spaced latitudes to produce a complete light curve. As discovered in 2021, Pompeja alongside the main-belt asteroid 269 Justitia have very red colors due to tholins on its surface, similar to trans-Neptunian objects. These asteroids are therefore thought to have formed in the outer Solar System despite their current orbits within the asteroid belt.