194 Prokne

194 Prokne is a main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on March 21, 1879, in Clinton, New York, and named after Procne, the sister of Philomela in Greek mythology. Stellar occultations by Prokne have been observed twice, in 1984 from Italy and again in 1999 from Iowa (United States).

194 Prokne

Orbital diagram
Discovery
Discovered by	C. H. F. Peters, 1879
Discovery date	21 March 1879
Designations
MPC designation	(194) Prokne
Pronunciation	/ˈprɒkniː/[1]
Named after	Procne
Alternative designations	A879 FA
Minor planet category	Main belt
Adjectives	Proknean /prɒkˈniːən/[2]
Orbital characteristics[3]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	136.76 yr (49950 d)
Aphelion	3.2386 AU (484.49 Gm)
Perihelion	1.9930 AU (298.15 Gm)
Semi-major axis	2.6158 AU (391.32 Gm)
Eccentricity	0.23810
Orbital period (sidereal)	4.23 yr (1545.3 d)
Mean anomaly	42.282°
Mean motion	0° 13m 58.692s / day
Inclination	18.509°
Longitude of ascending node	159.32°
Argument of perihelion	163.24°
Earth MOID	0.986917 AU (147.6407 Gm)
Jupiter MOID	2.15988 AU (323.113 Gm)
TJupiter	3.295
Physical characteristics
Dimensions	168.42±4.1 km[3] 170.33±6.92 km[4]
Mass	(2.68±0.29)×1018 kg[4]
Mean density	1.03±0.16 g/cm3[4]
Synodic rotation period	15.679 h (0.6533 d)[3][5]
Geometric albedo	0.0528±0.003
Spectral type	C
Absolute magnitude (H)	7.68

Observations from the W. M. Keck Observatory show the asteroid to be around 151 km across, with a size ratio of 1.13±0.06 between the major and minor axes. For comparison, observations by the IRAS observatory gave a diameter of 164 km.^[6] The spectrum matches a classification of a C-type asteroid, indicating it has a primitive carbonaceous composition. Judging from radar data, the near surface solid density of the asteroid is 3.6^+1.1
_−0.9 g cm⁻³.^[7]

Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 15.679±0.001 hours and varies in brightness by 0.16±0.02 in magnitude.^[5]