The atmospheric impact trajectory of asteroid 2014 AA

TL;DR

This study accurately determines the atmospheric impact trajectory of asteroid 2014 AA using combined optical and infrasonic data, significantly reducing orbit uncertainties and estimating impact parameters and energy.

Contribution

It introduces a method that combines optical astrometry and infrasonic detection to improve orbit estimation and impact predictions for small near-Earth asteroids.

Findings

Impact time with 6-minute uncertainty

Impact location within 140 km accuracy

Estimated minimum impact energy of 22.6 tons

Abstract

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.