2004 FU162 is an Aten near-Earth asteroid less than 20 meters in diameter crudely estimated to have passed roughly 6500 km above the surface of Earth[lower-alpha 2] on 31 March 2004.
| Designations | |
|---|---|
MPC designation | 2004 FU162 |
Minor planet category | Aten · NEO[1][2] |
| Orbital characteristics[1] | |
| Epoch 5 April 2004 (JD 2453100.5) | |
| Uncertainty parameter 9 | |
| Observation arc | 44 minutes[2][lower-alpha 1] (only 4 observations) |
| Aphelion | 1.1511 AU |
| Perihelion | 0.5026 AU |
Semi-major axis | 0.8269 AU |
| Eccentricity | 0.3922 |
Orbital period (sidereal) | 0.75 yr (275 days) |
Mean anomaly | 262.67° |
Mean motion | 1° 18m 39.24s / day |
| Inclination | 4.1647° |
Longitude of ascending node | 191.25° |
Argument of perihelion | 139.78° |
| Earth MOID | 0.0001 AU |
| Physical characteristics | |
| Dimensions | 4–12 meters (estimated) |
Absolute magnitude (H) | 28.7[1] |
It was only observed for 44 minutes on 31 March 2004,[lower-alpha 1] by the Lincoln Near-Earth Asteroid Research (LINEAR) team at Lincoln Laboratory's Experimental Test Site in Socorro, New Mexico, and remains a lost asteroid.[2] The estimated 4 to 6 meter sized body made one of the closest known approaches to Earth.
On 31 March 2004, around 15:35 UTC, the asteroid is crudely estimated to have passed within approximately 1 Earth radius (REarth) or 6,400 kilometers of the surface of the Earth (or 2.02 REarth from Earth's center). But due to the very short observation arc, the uncertainty in the close approach distance is a large ±15000 km. By comparison, geostationary satellites orbit at 5.6 REarth and GPS satellites orbit at 3.17 REarth from the center of the Earth.
As of 2008[update] this was the third or fourth closest approach. The first observation of 2004 FU162 was not announced until 22 August 2004.
It was only observed four times in the space of 44 minutes and could not be followed up. Nevertheless, "the orbit is quite determinate and, given the exceptional nature of this close approach, the object is now receiving a designation".[3] No precovery images have been found.
2004 FU162 is estimated to be approximately 6 meters in diameter.[citation needed] This means that it would burn up from atmospheric friction before striking the ground in the case of an Earth impact.
On 26 March 2010, it may have come within 0.0825 AU (12.3 million km) of Earth,[4] but with an uncertainty parameter of 9,[1] the orbit is poorly determined.
Another, larger near-Earth asteroid, 2004 FH passed just two weeks prior to 2004 FU162.
A closer non-impacting approach to Earth was not known until 2008 TS26 on 9 October 2008.
| Asteroid | Date | Distance from surface of Earth |
Uncertainty in approach distance |
Reference |
|---|---|---|---|---|
| 2020 VT4 | 2020-11-13 | 374 km | ±25 km | data |
| 2020 QG | 2020-08-16 | 2946 km | ±20 km | data |
| 2021 UA1 | 2021-10-25 | 3047 km | ±20 km | data |
| 2011 CQ1 | 2011-02-04 | 5481 km | ±5 km | data |
| 2019 UN13 | 2019-10-31 | 6242 km | ±200 km | data |
| 2008 TS26 | 2008-10-09 | 6259 km | ±1000 km | data |
| 2004 FU162 | 2004-03-31 | 6542 km | ±15000 km | data |
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