1633 Chimay

1633 Chimay, provisional designation 1929 EC, is a Themistian asteroid from the outer region of the asteroid belt, approximately 37 kilometers in diameter.

1633 Chimay

Lightcurve based 3D-model of Chimay
Discovery[1]
Discovered by	S. Arend
Discovery site	Uccle Obs.
Discovery date	3 March 1929
Designations
MPC designation	(1633) Chimay
Named after	Chimay (Belgian town)[2]
Alternative designations	1929 EC · 1941 KF 1946 HC · 1948 RO 1951 AM · 1952 HY3 1954 SS · 1955 XN 1972 VM1 · A917 BB
Minor planet category	main-belt · Themis[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	100.02 yr (36,531 days)
Aphelion	3.5907 AU
Perihelion	2.7980 AU
Semi-major axis	3.1943 AU
Eccentricity	0.1241
Orbital period (sidereal)	5.71 yr (2,085 days)
Mean anomaly	237.33°
Mean motion	0° 10m 21.36s / day
Inclination	2.6759°
Longitude of ascending node	114.08°
Argument of perihelion	65.539°
Physical characteristics
Dimensions	36.07 km (derived)[3] 36.12±3.1 km (IRAS:3)[4] 36.26±0.86 km[5] 37.428±0.466[6] 37.732±0.426 km[7]
Synodic rotation period	6.58±0.01 h[8] 6.59064±0.00005 h[9] 6.5911±0.0001 h[10] 6.6367±0.0038 h[11]
Geometric albedo	0.0781 (derived)[3] 0.0785±0.0135[7] 0.080±0.014[6] 0.0854±0.017 (IRAS:3)[4] 0.088±0.005[5]
Spectral type	S[3]
Absolute magnitude (H)	10.36±0.17 (R)[8] · 10.481±0.002 (R)[11] · 10.5[5][7] · 10.6[1][3] · 10.97±0.06[12]

It was discovered on 3 March 1929, by Belgian astronomer Sylvain Arend at the Royal Observatory of Belgium in Uccle.^[13] Five nights later, the body was independently discovered by Max Wolf at Heidelberg Observatory in southern Germany.^[2] It was later named for the Belgian town of Chimay.^[2]

Classification and orbit

Chimay is a member of the Themis family, a dynamical family of asteroids with nearly coplanar ecliptical orbits. It orbits the Sun in the outer main-belt at a distance of 2.8–3.6 AU once every 5 years and 9 months (2,085 days). Its orbit has an eccentricity of 0.12 and an inclination of 3° with respect to the ecliptic.^[1] Chimay was first identified as A917 BB at Heidelberg in 1917, extending the body's observation arc by 12 years prior to its official discovery observation.^[13]

Physical characteristics

Several rotational lightcurves were obtained from photometric observations. Lightcurve analysis gave a well-defined, concurring rotation period of 6.58–6.63 hours with a brightness variation between 0.31 and 0.58 magnitude (U=3/3-/2).^{[8][9][10][11][14]}

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Chimay measures between 36.1 and 37.7 kilometers in diameter, and its surface has a low albedo between 0.079 and 0.089.^[4][5][6][7] In accordance with the space-based surveys, the Collaborative Asteroid Lightcurve Link (CALL) derives an albedo of 0.078, and calculates a diameter of 36.1 kilometers. CALL also classifies Chimay as a S-type rather than a carbonaceous C-type asteroid.^[3]

Naming

This minor planet was named after the Belgian town Chimay, home of the discoverer, who also co-discovered Comet Arend–Roland.^[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3931).^[15]