On the Proposed Interstellar Origin of the USG 20140108 Fireball

TL;DR

This paper critically reviews the evidence for the interstellar origin of the USG 20140108 fireball, highlighting uncertainties in velocity measurements and suggesting the fireball's high speed is likely overestimated.

Contribution

It provides a detailed analysis of velocity uncertainties and ablation modeling, challenging the interstellar origin hypothesis for the fireball.

Findings

USG fireball velocity uncertainties are significant and variable.

Ablation models fit normal impactors only at low speeds.

The fireball's high speed is likely overestimated.

Abstract

A critical review of the evidence for the interstellar origin for the USG 20140108 fireball is presented. Examining USG fireball velocities where independent data are available shows the former to have significant (10-15 km/s) uncertainties at large speeds and highly variable radiant accuracy, with average errors in excess of ten degrees. Ablation model fits to the observed lightcurve are possible for normal chondritic impactors only assuming low speeds. To match the high speed and low fragmentation height of the USG 20140108 fireball would require a high density/strength object with low drag and highly aerodynamic shape not made of iron. We suggest the simpliest explanation for the unusual characteristics of USG 20140108 is that the speed, in particular, is substantially overestimated.