2014 AA

2014 AA

Probable impact location of near-Earth asteroid 2014 AA based on infrasound data from the Comprehensive Nuclear-Test-Ban Treaty Organization.[1]
Discovery[2]
Discovered by Richard Kowalski
Mount Lemmon Survey (G96)
Discovery date 1 January 2014
Designations
MPC designation 2014 AA
Apollo NEO[3]
Orbital characteristics[3]
Epoch 2014-Jan-01
(Uncertainty=8)[3]
Observation arc ~70 minutes[2]
Aphelion 1.41 AU (Q)
Perihelion 0.91 AU (q)
1.16 AU (a)
Eccentricity 0.21
1.3 yr
324° (M)
Inclination 1.4°
102°
52°
Physical characteristics
Dimensions ~3 meters (10 ft)
Mass ~4×104 kg (assumed)
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]

    Entry

    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] 3,000 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

    1. ↑ 1.0 1.1 1.2 1.3 1.4 "The First Discovered Asteroid of 2014 Collides With The Earth - An Update". NASA/JPL. 3 January 2014. Retrieved 4 January 2014.
    2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "MPEC 2014-A02 : 2014 AA". IAU Minor Planet Center. 2 January 2014. Retrieved 2 January 2014. (K14A00A)
    3. ↑ 3.0 3.1 3.2 3.3 "JPL Small-Body Database Browser: (2014 AA)" (last observation: 1 January 2014; arc: 1 day). Jet Propulsion Laboratory. Retrieved 2 January 2014.
    4. ↑ "JPL Close-Approach Data: (2014 AA)" (last observation: 1 January 2014; 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. ↑ 6.0 6.1 6.2 6.3 Beatty, Kelly (2 January 2014). "Small Asteroid 2014 AA Hits Earth". Sky & Telescope. Retrieved 3 January 2014.

    External links