|Discovered by||Catalina Sky Survey (703)|
|Discovery date||11 September 2009|
|MPC designation||2009 RR|
|Minor planet category||Apollo NEO|
|Aphelion||2.06 AU (Q)|
|Perihelion||0.7513 AU (q)|
|1.406 AU (a)|
|Dimensions||~26 meters (85 ft)
|Mass||2.4×107 kg (assumed)|
2009 RR is a near-Earth asteroid. It was discovered on 11 September 2009 by the Catalina Sky Survey at an apparent magnitude of 19.5 using a 0.68-meter (27 in) Schmidt–Cassegrain telescope. 2009 RR was the only asteroid discovered before 2014 that was predicted to potentially pass inside the orbit of the Moon during 2014. The asteroid has an estimated diameter of 26 meters (85 ft) and is listed on the Sentry Risk Table. It is not large enough to qualify as a potentially hazardous object.
With an observation arc of only 4 days, the asteroid has a poorly determined orbit. It is already known that there is no risk of an Earth impact before 2098. The power of such an air burst would be somewhere between the Chelyabinsk meteor and the Tunguska event depending on the actual size of the asteroid.
The nominal orbit shows that on 16 September 2014 the asteroid could have passed just inside one lunar distance from Earth, but the orbital uncertainties show that it could have passed as much as 0.1 AU (15,000,000 km; 9,300,000 mi) from Earth. On 9 September 2014 the full moon may have only be 15 degrees from the 20th magnitude asteroid, making it difficult to detect the asteroid. The asteroid was estimated to be brighter than magnitude 20 from 10 September until 16 September 2014. 2009 RR was not recovered during the 2014 approach and thus probably passed more than one lunar distance from Earth.
- "MPEC 2009-R39 : 2009 RR". IAU Minor Planet Center. 2009-09-11. Retrieved 2014-01-13. (K09R00R)
- "JPL Small-Body Database Browser: (2009 RR)" (last observation: 2009-09-15; arc: 4 days). Jet Propulsion Laboratory. Retrieved 2014-08-05.
- "Earth Impact Risk Summary: 2009 RR". NASA/JPL Near-Earth Object Program Office. Retrieved 2014-01-13.
- "2009RR Ephemerides for September 2014". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 2014-01-15.
- "JPL Close-Approach Data: (2009 RR)" (last observation: 2009-09-15; arc: 4 days). Retrieved 2014-01-13.