2011 MD

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2011 MD
2011MD in February 2014
(Spitzer Space Telescope, IRAC).
Discovered by LINEAR (704)
Discovery date 2011 June 22
Amor NEO[2]
Orbital characteristics[2]
Epoch 11 July 2011 (JD 2455753.5)
Uncertainty parameter 1
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)
0° 54m 10.224s /day
Inclination 2.5837°
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]

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]


2011MD on 26 June 2011

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




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°

Trajectory plots[edit]

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.

See also[edit]


  1. ^ "MPEC 2011-M23 : 2011 MD". IAU Minor Planet Center. 2011-06-23. Retrieved 2013-01-05.  (K11M00D)
  2. ^ a b c d e f g NASA JPL. "JPL Small-Body Database Browser (2011 MD)". Retrieved 31 March 2016. 
  3. ^ a b c d NASA JPL. "NASA Announces Latest Progress in Hunt for Asteroids". Retrieved 2014-06-19. 
  4. ^ a b c Mommert, M.; et al. (2014). "Physical properties of near-earth asteroid 2011 MD". Astrophys. J. 789: L22. Bibcode:2014ApJ...789L..22M. arXiv:1406.5253Freely accessible. doi:10.1088/2041-8205/789/1/L22. 
  5. ^ 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. 
  6. ^ a b c Tony Flanders (June 23, 2011). "Asteroid To Buzz Earth Monday, June 27th". Sky & Telescope observing blog. Retrieved June 27, 2011. 
  7. ^ "Asteroid Just Buzzed Earth—Came Closer Than the Moon". 
  8. ^ a b 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. 
  9. ^ Borenstein, Seth (June 19, 2014). "Rock that whizzed by Earth may be grabbed by NASA". AP News. Retrieved June 20, 2014. 

External links[edit]