2014 AA

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2014 AA
2014aa imploc.png
Discovery[2]
Discovered by Richard Kowalski
Mount Lemmon Survey (G96)
Discovery date 1 January 2014
Designations
MPC designation 2014 AA
Minor planet category Apollo NEO[3]
Orbital characteristics[3]
Epoch 2014-Jan-01
(Uncertainty=8)[3]
Aphelion 1.41 AU (Q)
Perihelion 0.91 AU (q)
Semi-major axis 1.16 AU (a)
Eccentricity 0.21
Orbital period 1.3 yr
Mean anomaly 324° (M)
Inclination 1.4°
Longitude of ascending node 102°
Argument of perihelion 52°
Physical characteristics
Dimensions ~3 meters (10 ft)
Mass ~4×104 kg (assumed)
Absolute magnitude (H) 30.9[3]

2014 AA was a small near-Earth asteroid roughly 2–4 meters in diameter that struck Earth on 2 January 2014.[2] It was discovered on 1 January 2014 by Richard Kowalski at the Mount Lemmon Survey at an apparent magnitude of 19 using a 1.52-meter (60 in) reflecting telescope at Mount Lemmon Observatory.[2] 2014 AA was only observed over a short observation arc of about 70 minutes,[2] and entered Earth's atmosphere about 21 hours after discovery.[1]

Using a poorly determined orbit, the JPL Small-Body Database listed a 3-sigma solution with impact occurring around 2 January 2014 02:33 UT ± 1 hour and 5 minutes.[4] The Minor Planet Center listed impact as occurring around 2 January 2014 05:00 UT ± 10 hours.[2] Independent calculations by Bill Gray, the Minor Planet Center and Steve Chesley at the Jet Propulsion Laboratory have verified that impact was virtually certain.[2] The impactor would have been roughly the size of 2008 TC3, which exploded above the Nubian Desert in Sudan on 7 October 2008. Calculations by Chesley suggest the impactor fell somewhere on an arc extending from Central America to East Africa, with a best-fit location just off the coast of West Africa.[2] Calculations by Pasquale Tricarico using the nominal orbit show that 2014 AA entered Earth's shadow cone approximately 40 minutes before entering the atmosphere.[5]

Infrasound was detected by three stations of the Comprehensive Nuclear-Test-Ban Treaty Organization.[6] Peter Brown and Petrus Jenniskens located weak signals from infrasound stations in Bolivia, Brazil and Bermuda.[1] 2014 AA entered Earth's atmosphere around 04:02 UT[1] 3000 km from Caracas, Venezuela, far from any landmass.[6] No ships or planes have reported witnessing the event.[6]

Kowalski previously discovered 2008 TC3, the first asteroid discovered before Earth impact, using the same telescope in October 2008.[6] There are about a billion near-Earth objects in the size range of 2014 AA, and impacts of comparably-sized objects occur several times each year.[1]

References[edit]

  1. ^ a b c d e "The First Discovered Asteroid of 2014 Collides With The Earth - An Update". NASA/JPL. 3 January 2014. Retrieved 4 January 2014. 
  2. ^ a b c d e f g "MPEC 2014-A02 : 2014 AA". IAU Minor Planet Center. 2 January 2014. Retrieved 2 January 2014.  (K14A00A)
  3. ^ a b c d "JPL Small-Body Database Browser: (2014 AA)". Jet Propulsion Laboratory. 1 January 2014 last obs (arc=1 day). Retrieved 2 January 2014. 
  4. ^ "JPL Close-Approach Data: (2014 AA)". 1 January 2014 last obs (arc=1 day). Retrieved 2 January 2014. 
  5. ^ Guido, Ernesto (2 January 2014). "Small asteroid 2014 AA hit the Earth's atmosphere". Associazione Friulana di Astronomia e Meteorologia. Retrieved 2 January 2014. 
  6. ^ a b c d Beatty, Kelly (2 January 2014). "Small Asteroid 2014 AA Hits Earth". Sky & Telescope. Retrieved 3 January 2014. 

External links[edit]