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.[4] As discovered in 2021, the asteroid has a very red color due to tholins on its surface, similar to trans-Neptunian objects. It is therefore thought to have formed in the outer Solar System despite its current orbit within the asteroid belt.[5]
^ abPilcher, Frederick; et al. (July 2012), "Rotation Period Determination for 203 Pompeja - Another Triumph of Global Collaboration", The Minor Planet Bulletin, 39 (3): 99, Bibcode:2012MPBu...39...99P
^Hasegawa, Sunao; Marsset, Michaël; Demeo, Francesca E.; Bus, Schelte J.; Geem, Jooyeon; Ishiguro, Masateru; Im, Myungshin; Kuroda, Daisuke; Vernazza, Pierre (2021), "Discovery of two TNO-like bodies in the asteroid belt", The Astrophysical Journal Letters, 916 (1): L6, arXiv:2106.14991, Bibcode:2021ApJ...916L...6H, doi:10.3847/2041-8213/ac0f05, S2CID235669878