Comet Encounters and Carbon 14

TL;DR

This paper investigates the possibility that a comet impact could have caused a significant increase in atmospheric Carbon-14 in 775 CE, by analyzing shock-accelerated particle production and cosmic ray generation.

Contribution

It introduces a model linking cometary superflare events to high-energy particle production capable of explaining the CE 775 Carbon-14 anomaly.

Findings

A cometary superflare could produce enough energetic particles to account for the C-14 increase.

The required energy exceeds typical solar flares but is plausible for a large comet impact.

Future comet encounters may produce observable signatures similar to the CE 775 event.

Abstract

The $^{14}$C production of shock-accelerated particles is calculated in terms of the total energy released in energetic particles. The recently reported 1.2% jump in the $^{14}$C content of the atmosphere in the year C.E. 775, it is found, would require $\gtrsim 10^{34}$ erg in energetic particles, less than first estimates but far more than any known solar flare on record. It is noted that the superflare from a large comet (comparable to C/Hale-Bopp) colliding with the sun could produce shock-accelerated GeV cosmic rays in the solar corona and/or solar wind, and possibly account for the CE 775 event. Several additional predictions of cometary encounters with the sun and other stars may be observable in the future.