  Near-Earth asteroid 2014 AA entered the Earth's atmosphere on 2014 January 2,
only 21 hours 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 minutes, 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 1-sigma uncertainty of 6 min,
while the impact location corresponds to a west longitude of 44.7 deg and a
latitude of 13.1 deg with a 1-sigma 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.
