2011 MD

2011 MD is a bright micro-asteroid, classified as near-Earth object of the Apollo and Amor group, respectively. On 27 June 2011, at around 17:00 UTC (13:00 EDT), the object passed exceptionally close to Earth's surface at a distance of approximately 12000 km, roughly the diameter of the Earth.

Description


Although 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.

was discovered on 22 June 2011, by astronomers of the Lincoln Near-Earth Asteroid Research (LINEAR) at the U.S. Lincoln Laboratory Experimental Test Site in Socorro, New Mexico, by a pair of robotic telescopes. According to original rough estimates, the asteroid's length was between 10 and 45 m. However, according to the more recent absolute magnitude (H) measurement of 28.1 and its albedo of 0.3, the asteroid is closer to 6 meters or 20 feet 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 27 June 2011 close approach to Earth increased the orbital period of 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.

was observed by the Spitzer Space Telescope in February 2014 and estimated to be 6 m in diameter. The asteroid is a porous rubble pile with a density similar to water. On 19 June 2014, NASA reported that asteroid was a prime candidate for capture by the Asteroid Redirect Mission (ARM) in the early 2020s.