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(374158) 2004 UL is a sub-kilometer asteroid on an outstandingly eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group.[2] The object is known for having the second-smallest perihelion of any known asteroid, after (137924) 2000 BD19.[citation needed]

(374158) 2004 UL
Discovery [1]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date18 October 2004
MPC designation(374158) 2004 UL
2004 UL
Apollo · NEO · PHA[1][2]
Mercury crosser · Venus crosser · Earth crosser · Mars crosser
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc15.05 yr (5,498 days)
Aphelion2.4400 AU
Perihelion0.0928 AU
1.2664 AU
1.43 yr (521 days)
0° 41m 29.76s / day
Earth MOID0.0182 AU (7.1 LD)
Physical characteristics
Mean diameter
0.5–1.2 km (generic)[3]
0.516 km (calculated)[4]
38±2 h[5][a]
0.20 (assumed)[4]
B–V = 0.820±0.100[b]
V–R = 0.540±0.100[b]
18.77 (R)[b] · 18.8[1][4]

It was discovered on 18 October 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) at Lincoln Lab's ETS near Socorro, New Mexico.[2]

Orbit and classificationEdit

This Apollo asteroid orbits the Sun at a distance of 0.09–2.44 AU once every 17 months (521 days; semi-major axis of 1.27 AU). Its orbit has an outstandingly high eccentricity of 0.93 and an inclination of 24° with respect to the ecliptic.[1]

Due to its orbit, it is also a Mercury-crosser, Venus-crosser and Mars-crosser. It has an Earth minimum orbital intersection distance of 0.0182 AU (2,720,000 km), which translates into 7.1 lunar distances.[1]

Physical characteristicsEdit

2004 UL is an assumed stony S-type asteroid.[4]

In October 2014, a rotational lightcurve for this asteroid was obtained from photometric observations by American astronomer Brian Warner at the CS3–Palmer Divide Station (U82) in Landers, California.[a] It gave a longer-than average rotation period of 38±2 hours (most minor planets take 2–20 hours to complete a full rotation) with a high brightness variation of 1.2 magnitude, indicating a non-spheroidal shape (U=2).[5]

Based on a generic magnitude-to-diameter conversion, 2004 UL measures between 0.5 and 1.2 kilometers.[3] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 0.516 kilometers with an absolute magnitude of 18.8.[4]

Numbering and namingEdit

This minor planet was numbered by the Minor Planet Center on 18 October 2013 (M.P.C. 85347).[6] As of 2018, it has not been named.[2]


  1. ^ a b Lightcurve plot for (374158) by B. D. Warner at the CS3-Palmer Divide Station from October/November 2014
  2. ^ a b c Jewitt (2013). Abs. magnitude of 18.77 (R). Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (374158)


  1. ^ a b c d e f "JPL Small-Body Database Browser: 374158 (2004 UL)" (2016-10-07 last obs.). Jet Propulsion Laboratory. Retrieved 1 June 2017.
  2. ^ a b c d "374158 (2004 UL)". Minor Planet Center. Retrieved 18 August 2016.
  3. ^ a b "NEODyS (374158) 2004UL". Near Earth Objects - Dynamic Site. Retrieved 7 March 2014.
  4. ^ a b c d e f "LCDB Data for (374158)". Asteroid Lightcurve Database (LCDB). Retrieved 18 August 2016.
  5. ^ a b Warner, Brian D. (April 2015). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 October-December". The Minor Planet Bulletin. 42 (2): 115–127. Bibcode:2015MPBu...42..115W. ISSN 1052-8091. Retrieved 18 August 2016.
  6. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 February 2018.

External linksEdit