(7563) 1988 BC

(7563) 1988 BC (provisional designation 1988 BC) is a background asteroid from the central region of the asteroid belt, approximately 16 kilometers (10 miles) in diameter. It was discovered on 16 January 1988, by Japanese amateur astronomer Takuo Kojima at the YGCO Chiyoda Station in the Kantō region of Japan.^[1] The asteroid has a rotation period of 6.5 hours.^[9]

(7563) 1988 BC

Discovery[1]
Discovered by	T. Kojima
Discovery site	YGCO Chiyoda Stn.
Discovery date	16 January 1988
Designations
MPC designation	(7563) 1988 BC
Alternative designations	1988 BC · 1991 VJ5
Minor planet category	main-belt[1][2] · (middle) background
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	30.03 yr (10,969 d)
Aphelion	3.2894 AU
Perihelion	2.0689 AU
Semi-major axis	2.6792 AU
Eccentricity	0.2278
Orbital period (sidereal)	4.39 yr (1,602 d)
Mean anomaly	299.98°
Mean motion	0° 13m 29.28s / day
Inclination	12.678°
Longitude of ascending node	83.534°
Argument of perihelion	52.920°
Physical characteristics
Mean diameter	12.04±3.52 km[3] 13.93±0.10 km[4] 15.857±0.103 km[5][6] 16.134±0.099 km[7] 17.27±0.64 km[8]
Synodic rotation period	6.539±0.005 h[9][10]
Geometric albedo	0.0483[7] 0.06[4] 0.073[8] 0.078[5] 0.078±0.015[6] 0.08[3]
Spectral type	S (assumed)[9]
Absolute magnitude (H)	12.30[5][7][8] 12.70[3] 12.8[1][2][9] 12.90[4]

Classification and orbit

1988 BC is non-family asteroid of the main belt's background population. It orbits the Sun in the central asteroid belt at a distance of 2.1–3.3 AU once every 4 years and 5 months (1,602 days; semi-major axis of 2.68 AU). Its orbit has an eccentricity of 0.23 and an inclination of 13° with respect to the ecliptic.^[2]

Naming

As of 2018, 1988 BC remains unnamed.^[1]

Physical characteristics

Lightcurves

In January 2010, a rotational lightcurve of 1988 BC was obtained from photometric observations by Pierre Antonini at the Bédoin Observatory (132) in southeastern France. Lightcurve analysis gave a rotation period of 6.539±0.005 hours with a brightness variation of 0.30 in magnitude (U=3).^[10] A previous 2006-observation by American astronomer Brian Warner at his Palmer Divide Observatory in Colorado gave a period of 6.510 hours and an amplitude of 0.24 magnitude (U=3-).^[11]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid has a low albedo of between 0.048 and 0.08, with a diameter between 12.04 and 17.27 kilometers.^[6][7][8]

Despite the results from the space-based observations, the Collaborative Asteroid Lightcurve Link assumes a higher albedo of 0.10 – a compromise between the stony and carbonaceous asteroid populations from the inner and outer main-belt, respectively – and hence calculates a smaller diameter of 12.1 kilometers with an absolute magnitude of 12.7.^[9]