3254 Bus

3254 Bus, provisional designation 1982 UM, is a rare-type Hildian asteroid from the outermost region of the asteroid belt, approximately 32 kilometers in diameter. It was discovered on 17 October 1982, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station in Flagstaff, Arizona.^[3] It is named after astronomer Schelte J. Bus.^[2]

3254 Bus

Discovery[1]
Discovered by	E. Bowell
Discovery site	Anderson Mesa Stn.
Discovery date	17 October 1982
Designations
MPC designation	(3254) Bus
Named after	Schelte J. Bus (American astronomer)[2]
Alternative designations	1982 UM · 1982 SW4
Minor planet category	main-belt[1] · Hilda[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	34.69 yr (12,671 days)
Aphelion	4.6044 AU
Perihelion	3.3052 AU
Semi-major axis	3.9548 AU
Eccentricity	0.1643
Orbital period (sidereal)	7.86 yr (2,873 days)
Mean anomaly	182.71°
Mean motion	0° 7m 31.08s / day
Inclination	4.4462°
Longitude of ascending node	43.479°
Argument of perihelion	305.67°
Jupiter MOID	0.8515 AU
Physical characteristics
Dimensions	31.104±0.895 km[5] 32.03 km (calculated)[4] 35.07±0.95 km[6]
Synodic rotation period	6.62 h[7]
Geometric albedo	0.057 (assumed)[4] 0.058±0.003[6] 0.073±0.002[5]
Spectral type	SMASS = T[1] D[5] · T[4]
Absolute magnitude (H)	11.00[6] · 11.2[1][4]

Orbit and classification

Located in the outermost part of the main-belt, Bus is a member of the Hilda family, a large orbital group of asteroids that are thought to have originated from the Kuiper belt.^[3] It orbits the Sun at a distance of 3.3–4.6 AU once every 7 years and 10 months (2,873 days). Its orbit has an eccentricity of 0.16 and an inclination of 4° with respect to the ecliptic.^[1] It was first identified as 1982 SW₄ at Crimea–Nauchnij, extending the body's observation arc by 3 weeks prior to its official discovery observation at Flagstaff.^[3]

Physical characteristics

In the SMASS taxonomy, Bus is a rare T-type asteroid, while NASA's Wide-field Infrared Survey Explorer (WISE) characterizes Bus as a dark D-type asteroid.^[1][5]

Rotation period

In the late 1980s or early 1990s, a rotational lightcurve of Bus was obtained from photometric observations by American astronomer Richard P. Binzel. Lightcurve analysis gave a rotation period of 6.62 hours with a brightness variation of 0.31 magnitude (U=2).^[7]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the WISE spacecraft with its subsequent NEOWISE mission, Bus measures 31.104 and 35.07 kilometers in diameter and its surface has an albedo of 0.058 and 0.073, respectively.^[5][6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 32.03 kilometers using an absolute magnitude of 11.2.^[4]

Naming

This minor planet was named after American astronomer Schelte J. Bus, a prolific discoverer of minor planets and comets.^[2] The approved naming citation was published by the Minor Planet Center on 2 July 1985 (M.P.C. 9771).^[8]