| Discovery[1][2] | |
|---|---|
| Discovered by | Pan-STARRS 1 |
| Discovery site | Haleakala Obs. |
| Discovery date | 30 June 2011 |
| Designations | |
| (458732)2011 MD5 | |
| 2011 MD5 | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 8.67yr (3,165 d) |
| Aphelion | 3.9869AU |
| Perihelion | 0.9895 AU |
| 2.4882 AU | |
| Eccentricity | 0.6023 |
| 3.92 yr (1,434 d) | |
| 49.188° | |
| 0° 15m 3.96s / day | |
| Inclination | 10.553° |
| 170.34° | |
| 224.84° | |
| Earth MOID | 0.0627 AU (24.4 LD) |
| Physical characteristics | |
| 730–1,600m(CNEOS)[4] 0.8 km[5] 1.2 km | |
| 17.8[3] 17.9[2] | |
(458732) 2011 MD5 is anApollonear-Earth asteroid around 1.2 kilometers (0.75 miles) in diameter. It is the largest asteroid known to have passed closer than the Moon.[4] On 17 September 1918 the asteroid passed 0.00234 AU (350,000 km; 0.91 LD) from Earth[3] with a peakapparent magnitude of around 8.4. The 1918 close approach distance is known with an accuracy of roughly ±120 km. The asteroid had come toopposition (opposite the Sun in the sky) on 9 August 1918 at magnitude 16.
2011 MD5 was not discovered until 30 June 2011,[1] when the asteroid was 1.3 AU (190 million km) from Earth. As of 2023, the asteroid has a 12-yearobservation arc and a well-determined orbit.
