2011MD on 26 June 2011
|Discovered by||LINEAR (704)|
|Discovery date||2011 June 22|
|Minor planet category||Amor NEO|
|Semi-major axis||1.056 AU|
|Orbital period||396.5 d|
|Longitude of ascending node||271.6°|
|Argument of perihelion||5.838°|
|Dimensions||7 - 15 meters
|Rotation period||0.1937 h|
|Absolute magnitude (H)||28.1|
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. Although the object was initially believed to be space junk, subsequent observations confirmed that it is an asteroid.
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.
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). But based on the more recent absolute magnitude (H) of 28.1, the asteroid would be closer to 7 to 15 meters in diameter.
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.
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 with a geocentric eccentricity of 1.1.
Trajectory of 2011 MD projected onto the Earth's orbital plane. Note from this viewing angle, the asteroid passes underneath the Earth.
Trajectory of 2011 MD from the general direction of the Sun.
- "MPEC 2011-M23 : 2011 MD". IAU Minor Planet Center. 2011-06-23. Retrieved 2013-01-05. (K11M00D)
- NASA JPL. "JPL Small-Body Database Browser (2011 MD)". Retrieved 2013-01-05.
- "Conversion of Absolute Magnitude to Diameter". Minor Planet Center. Retrieved 2012-05-30.
- Don Yeomans & Paul Chodas (June 23, 2011). "Bend it Like Beckham! Small Asteroid to Whip Past Earth on June 27, 2011". NASA/JPL Near-Earth Object Program Office. Archived from the original on 4 July 2011. Retrieved June 26, 2011.
- Tony Flanders (June 23, 2011). "Asteroid To Buzz Earth Monday, June 27th". Sky & Telescope observing blog. Retrieved June 27, 2011.
- "Asteroid Just Buzzed Earth—Came Closer Than the Moon".
- Paul Sutherland (June 23, 2011). "Incoming! Another asteroid to skim by". Skymania: Astronomy and space guide. Archived from the original on 1 July 2011. Retrieved June 26, 2011.
|Wikimedia Commons has media related to 2011 MD.|
- Encounter animations (Pasquale Tricarico)