(38984) 2000 UZ4

(38984) 2000 UZ₄ (provisional designation 2000 UZ₄) is carbonaceous Zhongguo asteroid from the outermost regions of the asteroid belt, approximately 5 kilometers (3 miles) in diameter. It was discovered on 24 October 2000, by astronomers with Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States.^[1] The likely elongated C-type asteroid has a rotation period of 19.20 hours.^[3]

(38984) 2000 UZ₄

Discovery[1]
Discovered by	LINEAR
Discovery site	Lincoln Lab's ETS
Discovery date	24 October 2000
Designations
MPC designation	(38984) 2000 UZ4
Alternative designations	2000 UZ4
Minor planet category	main-belt[1] · (outer)[2][3] Zhongguo[4] · 2:1 res[5]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	20.39 yr (7,447 d)
Aphelion	4.1195 AU
Perihelion	2.5141 AU
Semi-major axis	3.3168 AU
Eccentricity	0.2420
Orbital period (sidereal)	6.04 yr (2,206 d)
Mean anomaly	312.38°
Mean motion	0° 9m 47.52s / day
Inclination	0.4882°
Longitude of ascending node	59.710°
Argument of perihelion	357.34°
Physical characteristics
Mean diameter	4.87 km (calculated)[3]
Synodic rotation period	19.20±0.390 h[6]
Geometric albedo	0.057 (assumed)[3]
Spectral type	C[3][7]
Absolute magnitude (H)	14.6[2] 14.840±0.190 (R)[6] 15.19±0.14[7] 15.29[3]

Orbit and classification

2000 UZ₄ is a non-family asteroid from the main belt's background population, and a member of the small group of Zhongguo asteroids,^[4] located in the Hecuba gap and locked in a 2:1 mean-motion resonance with the gas giant Jupiter. Contrary to the nearby unstable Griqua group, the orbits of the Zhongguos are stable over half a billion years.^[4][5]

It orbits the Sun in the outer main-belt at a distance of 2.5–4.1 AU once every 6.04 years (2,206 days; semi-major axis of 3.32 AU). Its orbit has an eccentricity of 0.24 and an inclination of 0° with respect to the ecliptic.^[2] The body's observation arc begins with a precovery taken by Spacewatch in February 1996, more than 4 years prior to its official discovery observation at Socorro.^[1]

Physical characteristics

2000 UZ₄ has been characterized as a carbonaceous C-type asteroid by Pan-STARRS' large-scale survey.^[3]

Rotation period

In January 2014, a rotational lightcurve of this asteroid was obtained from photometric observations in the R-band by astronomers at the Intermediate Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 19.20 hours with a high brightness amplitude of 0.70 magnitude, indicative of an elongated shape (U=2).^[6]

Diameter and albedo

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 4.87 kilometers based on an absolute magnitude of 15.29.^[3]

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 28 March 2002, after its orbit had sufficiently been secured (M.P.C. 45198).^[8] As of 2018, it has not been named.^[1]