203 Pompeja

203 Pompeja is a fairly large main-belt asteroid. It was discovered by C. H. F. Peters on September 25, 1879, in Clinton, New York, and named after Pompeii, the Roman town destroyed in volcanic eruption in AD 79. This asteroid is orbiting the Sun at a distance of 2.74 AU with an eccentricity (ovalness) of 0.06 and a period of 4.53 yr. The orbital plane is tilted at an angle of 3.2° to the plane of the ecliptic.^[2]

203 Pompeja

Orbital diagram
Discovery
Discovered by	C. H. F. Peters
Discovery date	25 September 1879
Designations
MPC designation	(203) Pompeja
Pronunciation	/pɒmˈpiːə/[1]
Named after	Pompeii
Alternative designations	A879 SA, 1895 EA
Minor planet category	Main belt
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	136.43 yr (49,832 d)
Aphelion	2.897 AU (433.4 Gm)
Perihelion	2.577 AU (385.5 Gm)
Semi-major axis	2.737 AU (409.4 Gm)
Eccentricity	0.058490
Orbital period (sidereal)	4.53 yr (1,653.6 d)
Average orbital speed	18.01 km/s
Mean anomaly	47.6383°
Mean motion	0° 13m 3.72s / day
Inclination	3.1780°
Longitude of ascending node	347.916°
Argument of perihelion	57.060°
Physical characteristics
Mean diameter	124.592±1.079 km[2]
Mass	(1.251 ± 0.640/0.401)×1018 kg[3]
Mean density	1.626 ± 0.831/0.521 g/cm3[3][a]
Synodic rotation period	24.052 h (1.0022 d)[4][2]
Geometric albedo	0.036±0.006[2]
Spectral type	DCX:
Absolute magnitude (H)	8.97[2]

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, 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.^[5]

Notes

1. Assuming a diameter of 113.68 ± 6.55 km.