|Discovered by||Mount Lemmon Srvy.|
|Discovery date||5 September 2010|
|MPC designation||2010 RF12|
|Epoch 13 January 2016 (JD 2457400.5)|
|Uncertainty parameter 3|
|Observation arc||3.1 days|
|Aphelion||1.2601 AU (188.51 Gm) (Q)|
|Perihelion||0.86087 AU (128.784 Gm) (q)|
|1.0605 AU (158.65 Gm) (a)|
|1.09 yr (398.89 d)|
|0° 54m 9s /day (n)|
|Earth MOID||0.000472692 AU (70,713.7 km)|
|Jupiter MOID||3.94203 AU (589.719 Gm)|
|Dimensions||~7 meters (23 ft)|
6–14 m (20–46 ft)
|Mass||5×105 kg (assumed)|
2010 RF12 is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, that passed between Earth and the Moon on 8 September 2010, at 21:12 UTC, approaching Earth within 79,000 kilometres (49,000 mi) above Antarctica. It is listed on the Sentry Risk Table as the asteroid with the greatest known probability (5%) of impacting Earth.[note 1]
NASA's Near Earth Program estimates its size to be 7 metres (23 ft) in diameter with a mass of around 500 tonnes. 2010 RF12 will make many more close approaches to Earth, with the approach of September 5–6, 2095 having a 5% chance (1 in 20) of colliding with Earth. The nominal JPL Earth approach in 2095 is 0.000058 AU (8,700 km; 5,400 mi) with Earth having a radius of approximately 6,400 kilometres (4,000 mi). The nominal NEODyS orbit has the asteroid passing 0.0001 AU (15,000 km; 9,300 mi) from Earth on September 6, 2095, with an apparent magnitude of ~12. Due to the asteroid's relatively small size, there is very little danger of harm arising from such an impact; rather there would be an impressive fireball as the rock air bursts in the upper atmosphere. The power of the airburst would be somewhere between the 2–4 m Sutter's Mill meteorite and the 17 m Chelyabinsk meteor.
It was realized in 2017 that 2010 RF12 should be recoverable during its August 13, 2022 close approach of between 0.0669 AU (10,010,000 km; 6,220,000 mi) and 0.0701 AU (10,490,000 km; 6,520,000 mi). It will reach an apparent magnitude of +24.0 to +24.7, and its position will have an uncertainty of roughly 5 arcminutes, 1/6th the size of the full moon and well within the field of view of imaging cameras on large telescopes. It should be detectable during that approach by telescopes of least 2 meters diameter in good observing sites, and the improvement of the orbit from the precise August 2022 position will verify or rule out possible future impacts for the next century or so.
- 2010 RX30, a similar-sized asteroid that passed Earth the same day
- 2000 SG344, another near-Earth asteroid (may be Saturn V stage IV rocket booster)
- 2006 JY26
- Asteroid impact prediction
- List of asteroid close approaches to Earth, for other close approaches
- In practice many asteroids impact Earth every year but very few are discovered and predicted beforehand, see Asteroid impact prediction.
- "MPEC 2010-R41 : 2010 RF12". IAU Minor Planet Center. 5 September 2010. Retrieved 17 April 2014. (K10R12F)
- "JPL Close-Approach Data: (2010 RF12)" (last observation: 2010-09-08; arc: 3 days). Retrieved 31 March 2016.
- "Earth Impact Risk Summary: 2010 RF12". NASA/JPL Near-Earth Object Program Office. Archived from the original on 22 January 2017. Retrieved 16 April 2014.
- Harvard scientists keep an eye on wayward asteroids
- "Sentry Risk Table". NASA/JPL Near-Earth Object Program Office. Archived from the original on 11 September 2010. Retrieved 27 January 2018.
- Second Asteroid to Buzz Earth Later Today
- "Impactor Table: 2010RF12". NEODyS-2. Retrieved 16 April 2014. (1 in 12)
- "2010RF12 Ephemerides for 5−6 September 2095". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 17 April 2014.
- How a Near-Earth Object Impact Might Affect Society, 9 January 2003, Clark R. Chapman, SwRI, Boulder CO USA
- Deen, Sam. "2022 recovery of 2010 RF12?". Yahoo groups - Minor Planet Mailing List. Retrieved 19 October 2017.
- 2010 RF12 at the JPL Small-Body Database