322 Phaeo

322 Phaeo is an asteroid from the central regions of the asteroid belt, approximately 70 kilometers (43 miles) in diameter. It was discovered on 27 November 1891, by French astronomer Alphonse Borrelly at the Marseille Observatory in southern France.^[1] The presumably metallic X-type asteroid is the principal body of the Phaeo family and has a rotation period of 17.6 hours. It was named for the Greek mythological figure Phaeo, one of the Hyades or nymphs. Several other asteroids were named for other of the Hyades – 193 Ambrosia, 158 Koronis, 217 Eudora, and 308 Polyxo.^[10]

322 Phaeo

Orbital diagram
Discovery[1]
Discovered by	A. Borrelly
Discovery site	Marseille Obs.
Discovery date	27 November 1891
Designations
MPC designation	(322) Phaeo
Pronunciation	/ˈfiːoʊ/[2]
Named after	Φαιώ Phaiō[3] (Greek mythology)
Minor planet category	main-belt[1][4] · (middle) Phaeo[5][6]
Adjectives	Phaeoian /fiːˈoʊ.iən/
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	126.48 yr (46,198 d)
Aphelion	3.4656 AU
Perihelion	2.0960 AU
Semi-major axis	2.7808 AU
Eccentricity	0.2463
Orbital period (sidereal)	4.64 yr (1,694 d)
Mean anomaly	110.49°
Mean motion	0° 12m 45s / day
Inclination	8.0544°
Longitude of ascending node	252.36°
Argument of perihelion	115.00°
Physical characteristics
Mean diameter	69.855±0.320 km[7] 71.88 ± 4.32 km[8]
Mass	(1.86 ± 0.04) × 1018 kg[8]
Mean density	9.56 ± 1.73 g/cm3[8]
Synodic rotation period	17.5845±0.0001 h[9]
Geometric albedo	0.089±0.014[7]
Spectral type	Tholen = X[4] SMASS = X[4] B–V = 0.719[4] U–B = 0.230[4]
Absolute magnitude (H)	9.01[4]