(458732) 2011 MD5 is an Apollo near-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 thousand km; 0.91 LD) from Earth[3] with a peak apparent magnitude of around 8.4. The 1918 close approach distance is known with an accuracy of roughly ±120 km. The asteroid had come to opposition (opposite the Sun in the sky) on 9 August 1918 at magnitude 16.

(458732) 2011 MD5
Discovery[1][2]
Discovered byPan-STARRS 1
Discovery siteHaleakala Obs.
Discovery date30 June 2011
Designations
(458732) 2011 MD5
2011 MD5
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc8.67 yr (3,165 d)
Aphelion3.9869 AU
Perihelion0.9895 AU
2.4882 AU
Eccentricity0.6023
3.92 yr (1,434 d)
49.188°
0° 15m 3.96s / day
Inclination10.553°
170.34°
224.84°
Earth MOID0.0627 AU (24.4 LD)
Physical characteristics
730–1600 m (CNEOS)[4]
0.8 km[5]
1.2 km
17.8[3]
17.9[2]

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-year observation arc and a well determined orbit.

References

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  1. ^ a b "MPEC 2011-N15 : 2011 MD5". IAU Minor Planet Center. 3 July 2011. Retrieved 14 June 2020. (K11M05D)
  2. ^ a b c "458732 (2011 MD5)". Minor Planet Center. Retrieved 15 June 2020.
  3. ^ a b c d "JPL Small-Body Database Browser: 458732 (2011 MD5)". Jet Propulsion Laboratory. Archived from the original on 2 May 2020. Retrieved 14 June 2020.
  4. ^ a b NEO Earth Close Approaches @ JPL CNEOS
    Select "Nominal dist <= 1 LD", "Past only", Sort by "H (mag)"
  5. ^ "LCDB Data for (458732)". Asteroid Lightcurve Database (LCDB). Retrieved 15 June 2020.
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