238 Hypatia

238 Hypatia is a large main-belt asteroid that was discovered by Russian astronomer Viktor Knorre on July 1, 1884, in Berlin. It was the third of his four asteroid discoveries. The name was given in honour of philosopher Hypatia of Alexandria. Based upon the spectrum, it is classified as a C-type asteroid^[4] and is probably composed of primitive carbonaceous material. Like many asteroids of this type, its surface is very dark in colour.

Orbit of Hypatia (blue ring)

238 Hypatia

3D model based on lightcurve data
Discovery
Discovered by	Viktor Knorre
Discovery date	1 July 1884
Designations
MPC designation	(238) Hypatia
Pronunciation	/hɪˈpeɪʃiə/[1]
Named after	Hypatia
Alternative designations	A884 NA, 1947 HA
Minor planet category	Main belt
Adjectives	Hypatian
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	124.07 yr (45318 d)
Aphelion	3.1652 AU (473.51 Gm)
Perihelion	2.6514 AU (396.64 Gm)
Semi-major axis	2.9083 AU (435.08 Gm)
Eccentricity	0.088335
Orbital period (sidereal)	4.96 yr (1811.5 d)
Average orbital speed	17.47 km/s
Mean anomaly	170.00°
Mean motion	0° 11m 55.392s / day
Inclination	12.413°
Longitude of ascending node	183.89°
Argument of perihelion	210.750°
Physical characteristics
Dimensions	148.49±3.6 km[2] 146.13 ± 2.66 km[3]
Mass	(4.90 ± 1.70) × 1018 kg[3]
Mean density	2.99 ± 1.05 g/cm3[3]
Synodic rotation period	8.8749 h (0.36979 d)
Geometric albedo	0.0428±0.002
Spectral type	C
Absolute magnitude (H)	8.18

Photometric observations of this asteroid at the European Southern Observatory in 1981 gave a light curve with a period of 8.9 ± 0.1 hours and a brightness variation of 0.12 in magnitude.^[5] Stellar occultation events were observed for this asteroid during 2001 and 2005. The resulting chords provided cross-section diameter estimates of 146.5 and 145.3 km, respectively.^[6]