The trajectory and atmospheric impact of asteroid 2014 AA

Near-Earth asteroid 2014 AA entered the Earth’s atmosphere on 2014 January 2, only 21 h after being discovered by the Catalina Sky Survey. In this paper we compute the trajectory of 2014 AA by combining the available optical astrometry, seven ground-based observations over 69 min, and the International Monitoring System detection of the atmospheric impact infrasonic airwaves in a least-squares orbit estimation filter. The combination of these two sources of observations results in a tremendous improvement in the orbit uncertainties. The impact time is 3:05 UT with a 1σ uncertainty of 6 min, while the impact location corresponds to a west longitude of 44.2° and a latitude of 13.1° with a 1σ uncertainty of 140 km. The minimum impact energy estimated from the infrasound data and the impact velocity result in an estimated minimum mass of 22.6 t. By propagating the trajectory of 2014 AA backwards we find that the only window for finding precovery observations is for the three days before its discovery.

[1]  Benoit Carry,et al.  Density of asteroids , 2012, 1203.4336.

[2]  Marco Micheli,et al.  NEO follow-up, recovery and precovery campaigns at the ESA NEO Coordination Centre , 2015, Proceedings of the International Astronomical Union.

[3]  Yves Cansi,et al.  An automatic seismic event processing for detection and location: The P.M.C.C. Method , 1995 .

[4]  Orbital and physical characteristics of meter-scale impactors from airburst observations , 2015, 1511.07479.

[5]  T. B. Spahr,et al.  The Catalina Sky Survey for NEOs , 1998 .

[6]  P. Brown,et al.  Infrasound production by bolides: A global statistical study , 2012 .

[7]  Nicolas Brachet,et al.  Monitoring the Earth’s Atmosphere with the Global IMS Infrasound Network , 2010 .

[8]  T. C. Bache,et al.  Locating events with a sparse network of regional arrays , 1988 .

[9]  S. N. Milam,et al.  The impact and recovery of asteroid 2008 TC3 , 2009, Nature.

[10]  T. Jordan,et al.  Numerical Modelling of Instantaneous Plate Tectonics , 1974 .

[11]  A. Harris,et al.  The population of near-Earth asteroids , 2000 .

[12]  Paul W. Chodas,et al.  The Orbital Motion and Impact Circumstances of Comet Shoemaker-Levy 9 , 1996 .

[13]  G. Bierman.  Factorization methods for discrete sequential estimation , 1977 .

[14]  P. Brown,et al.  Infrasonic detection of a near‐Earth object impact over Indonesia on 8 October 2009 , 2011 .

[15]  M. Micheli,et al.  Systematic ranging and late warning asteroid impacts , 2015, 1504.00025.

[16]  W. Edwards.  Meteor Generated Infrasound: Theory and Observation , 2010 .