| Minorplanet: | yes |
| Background: |
|
| Discovered: | 18 October 2004 |
| Mpc Name: | (374158) 2004 UL |
| Alt Names: | 2004 UL |
| Epoch: | 4 September 2017 (JD 2458000.5) |
| Uncertainty: | 0 |
| Observation Arc: | 15.05 yr (5,498 days) |
| Perihelion: | 0.0928 AU |
| Semimajor: | 1.2664 AU |
| Eccentricity: | 0.9267 |
| Period: | 1.43 yr (521 days) |
| Mean Motion: | / day |
| Inclination: | 23.785° |
| Asc Node: | 39.575° |
| Arg Peri: | 149.57° |
| Moid: | 0.0182 AU (7.1 LD) |
| Albedo: | 0.20 |
is a sub-kilometer asteroid on an outstandingly eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. The object is known for having the second-smallest perihelion of any known asteroid, after .
It was discovered on 18 October 2004 by the Lincoln Near-Earth Asteroid Research (LINEAR) at Lincoln Lab's ETS near Socorro, New Mexico.
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.
Due to its orbit, it is also a Mercury-crosser, Venus-crosser and Mars-crosser. It has an Earth minimum orbital intersection distance of 0.0182AU, which translates into 7.1 lunar distances.
is an assumed stony S-type asteroid.
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 in Landers, California. It gave a longer-than average rotation period of 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 .
Based on a generic magnitude-to-diameter conversion, measures between 0.5 and 1.2 kilometers. 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.
This minor planet was numbered by the Minor Planet Center on 18 October 2013 . As of 2018, it has not been named.