| Discovery[1][2] | |
|---|---|
| Discovered by | Mount Lemmon Srvy. |
| Discovery site | Mount Lemmon Obs. |
| Discovery date | 5 September 2010 |
| Designations | |
| 2010 RF12 | |
| NEO · Apollo[1][3] | |
| Orbital characteristics[3] | |
| Epoch 2025-May-05 (JD 2460800.5) | |
| Uncertainty parameter 0(MPC)[1] 2(JPL)[3] | |
| Observation arc | 11.98 years |
| Aphelion | 1.261AU |
| Perihelion | 0.86155 AU |
| 1.0615 AU | |
| Eccentricity | 0.18834 |
| 1.094yr (399.441 d) | |
| 85.8° | |
| 0° 54m 4.68s / day | |
| Inclination | 0.88264° |
| 163.69° | |
| 2025-Jan-29[3] | |
| 267.43° | |
| Earth MOID | 0.00072 AU (108 thousand km; 0.28 LD) |
| Physical characteristics | |
| 7 m[4] 6–12 meters (CNEOS) | |
| 28.4[1][3] | |
2010 RF12 is a very smallasteroid, classified asnear-Earth object of theApollo group, that passed betweenEarth and theMoon on 8 September 2010, at 21:12 UTC, approaching Earth within 79,000 kilometres (49,000 mi) aboveAntarctica.[5] The asteroid was discovered by theMount Lemmon Survey nearTucson, Arizona on 5 September 2010 along with2010 RX30.[1][6] Based on a short 7-dayobservation arc from that apparation, it was listed for 12 years on theSentry Risk Table as the asteroid with the greatest known probability (5%) of impacting Earth.[7][note 1]2010 RF12 was rediscovered in August 2022,[8][1] and now has a 12-year observation arc and a much better known orbit. As of the December 2022 solution which accounts for nongravitational forces,[3] there is a 1-in-10 chance of an Earth impact on 5 September 2095.[4]
| Date | Impact probability | JPL Horizons nominal geocentric distance (AU) | uncertainty region (3-sigma) |
|---|---|---|---|
| 2095-09-06 00:06 ± 00:20 | 1:10 | 0.00035 AU (52 thousand km)[3] | ±180 thousand km[9] |
NASA's Near Earth Program estimates its size to be 7 meters (23 feet) in diameter with a mass of around 500 tonnes.[4]2010 RF12 will make many more close approaches to Earth.[3] Around 6 September 2095 it will pass52000±180000 km from Earth.[3][9] An asteroid roughly 7-meters in diameter impacting Earth would cause very little danger of harm, but a rather impressive fireball is expected (estimated in the risk table as nearly 9 KT of energy release[4]) as the rockairbursts in the upper atmosphere. Pebble sized fragments would likely fall to the ground at terminal velocity.[10] The power of the airburst would be somewhere between the 2–4 mSutter's Mill meteorite and the 17 mChelyabinsk meteor (which had 440 KT equivalent energy).[11] The approach in 2096 is poorly known because it is dependent on the September 2095 Earth approach.
| Date | Impact probability (1 in) | JPL Horizons nominal geocentric distance (AU) | NEODyS nominal geocentric distance (AU) | MPC nominal geocentric distance (AU) | Find_Orb nominal geocentric distance (AU) | uncertainty region (3-sigma) |
|---|---|---|---|---|---|---|
| 2095-09-05 23:46 | 10 | 0.00035 AU (52 thousand km) | 0.0008 AU (120 thousand km)[12] | 0.00066 AU (99 thousand km) | 0.00087 AU (130,000 km)[13] | ±180 thousand km[14] |
| 2096-09-04 21:50 | 22000 | 0.84 AU (126 million km)[15] | 0.18 AU (27 million km)[16] | 0.36 AU (54 million km) | 0.19 AU (28 million km)[17] | ±414 million km[15] |
On 17 February 2059 the asteroid will pass within 3.5 million km from Earth[3] and reach aboutapparent magnitude 22.6 by late February. On 10 September 1915 it passed463000±30000 km from Earth.[3]
