|Discovery site||Anderson Mesa Stn.|
|Discovery date||20 June 1999|
|(101869) 1999 MM|
|Apollo · NEO · PHA |
|Orbital characteristics |
|Epoch 4 September 2017 (JD 2458000.5)|
|Uncertainty parameter 0|
|Observation arc||8.67 yr (3,167 days)|
|2.07 yr (756 days)|
|0° 28m 33.96s / day|
|Earth MOID||0.0016 AU (0.6 LD)|
(101869) 1999 MM, provisional designation 1999 MM is a sub-kilometer asteroid on an eccentric orbit, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group. It was discovered on 20 June 1999, by the Lowell Observatory Near-Earth-Object Search (LONEOS) at its U.S. Anderson Mesa Station in Flagstaff, Arizona. The first observation was made by Catalina Sky Survey just 8 days before its official discovery.
The asteroid orbits the Sun at a distance of 0.6–2.6 AU once every 2 years and 1 month (756 days). Its orbit has an eccentricity of 0.61 and an inclination of 5° with respect to the ecliptic. It has a notably low Earth minimum orbit intersection distance of 0.0016 AU (240,000 km), which is less than one lunar distance, and also approaches Mars and Venus to within 15 million kilometers.
1999 MM's orbit is very similar to that of 69230 Hermes, which in 1937 made what was for decades the closest observed approach to Earth by an asteroid. Its nearest pass to Earth within at least a century of present was the 930,000 kilometers one in 1875. In 2090 it passes Venus at 788,000 kilometers.