2011MD in February 2014
(Spitzer Space Telescope, IRAC). | |
| Discovery[1] | |
|---|---|
| Discovered by | LINEAR (704) |
| Discovery date | 2011 June 22 |
| Designations | |
| Amor NEO[2] | |
| Orbital characteristics[2] | |
| Epoch 11 July 2011 (JD 2455753.5) | |
| Uncertainty parameter1 | |
| Observation arc | 967 days (2.65 yr) |
| Aphelion | 1.1044 AU (165.22 Gm) |
| Perihelion | 1.0161 AU (152.01 Gm) |
| 1.0602 AU (158.60 Gm) | |
| Eccentricity | 0.041638 |
| 1.09 yr (398.74 d) | |
| 9.1059° | |
| 0° 54m 10.224s /day | |
| Inclination | 2.5837° |
| 274.09° | |
| 4.6800° | |
| Earth MOID | 0.000351106 AU (52,524.7 km) |
| Jupiter MOID | 3.88352 AU (580.966 Gm) |
| Physical characteristics | |
| Dimensions | ~6 meters (20 ft)[3][4] |
Mean density | ~1 g/cm³ (rubble pile)[3] |
| 0.1937 h (0.00807 d)[2] | |
| 0.3[4] | |
| 28.0[2] | |
2011 MD is an Apollo asteroid that passed relatively close to Earth's surface — at a distance of about 12,000 kilometers (7,500 mi), roughly the diameter of the Earth — at around 17:00 UTC (13:00 EDT) on June 27, 2011.[2][5][6][7] Although the object was initially believed to be space junk, subsequent observations confirmed that it is an asteroid.[6]
A few hours before the asteroid's nearest approach in 2011, it appeared close to the Sun, so observations were possible for only a brief period. Backyard astronomers were able to observe it with telescopes from Australia, southern Africa, and the Americas.[6]
The asteroid was discovered on June 22, 2011, by the Lincoln Near-Earth Asteroid Research (LINEAR) pair of robotic telescopes in New Mexico, and according to original rough estimates, the asteroid's length was between 10 and 45 meters (30 and 150 ft).[8] However, according to the more recent absolute magnitude (H) measurement of 28.1[2] and its albedo of 0.3, the asteroid is closer to 6 meters in diameter.[4]
Emily Baldwin of Astronomy Now said that there was no threat of collision, and should the asteroid enter Earth's atmosphere, it would "mostly burn up in a brilliant fireball, possibly scattering a few meteorites", causing no likely harm to life or property on the ground.[8]
The June 27, 2011 close approach to Earth increased the orbital period of 2011 MD from 380 days to 396 days. During close approach the asteroid passed Earth at a relative speed of 6.7 km/s[2] with a geocentric eccentricity of 1.1.
2011 MD was observed by the Spitzer Space Telescope in February 2014 and estimated to be 6 meters (20 ft) in diameter.[3] The asteroid is a porous rubble pile with a density similar to water.[3] On June 19, 2014, NASA reported that asteroid 2011 MD was a prime candidate for capture by the Asteroid Redirect Mission (ARM) in the early 2020s.[9]
| Parameter | Epoch | aphelion (Q) |
perihelion (q) |
Semi-major axis (a) |
eccentricity (e) |
Period (p) |
inclination (i) |
Longitude ascending node (Ω) |
Mean anomaly (M) |
Argument of perihelion (ω) |
|---|---|---|---|---|---|---|---|---|---|---|
| Units | AU | (days) | (°) | |||||||
| Pre-flyby | 2011-Jun-01 | 1.043 | 1.006 | 1.025 | 0.01804 | 379.1 | 2.739° | 97.79° | 269.8° | 244.3° |
| Post-flyby | 2011-Aug-01 | 1.097 | 1.016 | 1.056 | 0.03875 | 396.9 | 2.477° | 273.0° | 29.09° | 4.734° |
{{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help); Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)
{{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
