280 Philia

280 Philia is a fairly large Main belt asteroid.^[2] It was discovered by Johann Palisa on 29 October 1888 at the Vienna Observatory.

280 Philia

Orbital diagram
Discovery
Discovered by	Johann Palisa
Discovery date	29 October 1888
Designations
MPC designation	(280) Philia
Pronunciation	/ˈfɪliə/
Named after	Philia (nymph)
Alternative designations	A888 UB
Minor planet category	Main belt
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	126.17 yr (46,083 d)
Aphelion	3.26133 AU (487.888 Gm)
Perihelion	2.62787 AU (393.124 Gm)
Semi-major axis	2.94460 AU (440.506 Gm)
Eccentricity	0.10756
Orbital period (sidereal)	5.05 yr (1,845.6 d)
Mean anomaly	52.7987°
Mean motion	0° 11m 42.212s / day
Inclination	7.44582°
Longitude of ascending node	9.91179°
Argument of perihelion	90.0510°
Physical characteristics
Dimensions	45.69±2.0 km
Synodic rotation period	70.26 h (2.928 d)
Geometric albedo	0.0444±0.004
Absolute magnitude (H)	10.9

Sparse data collected during a 1987 study indicated this asteroid has a rotation period of approximately 64 hours, which is much longer than can be continually observed from one site. During 2010−2011, an international collaboration to study the asteroid collected 9,037 photometric data points over 38 sessions. The resulting light curve analysis displays a rotation period of 70.26±0.03 h with a brightness variation of 0.15±0.02 in magnitude.^[3]