Has the Earth been exposed to numerous supernovae within the last 300 kyr?

TL;DR

This paper critically examines claims of numerous nearby supernovae in the last 300 kyr, finding that previous estimates are exaggerated and based on outdated data, thus invalidating the earlier conclusions.

Contribution

The study corrects previous overestimations by using updated datasets, demonstrating that the claimed frequency of supernovae near Earth in the last 300 kyr is unsupported.

Findings

Previous estimates of supernovae exposure are overestimated by four orders of magnitude.

Updated datasets do not support the occurrence of numerous nearby supernovae in the last 300 kyr.

Claims of frequent supernova-induced mass extinctions are invalidated.

Abstract

Firestone (2014) asserted evidence for numerous (23) nearby (d<300 pc) supernovae within the Middle and Late Pleistocene. If true, this would have strong implications for the irradiation of the Earth; at this rate, mass extinction level events due to supernovae would be more frequent than 100 Myr. However, there are numerous errors in the application of past research. The paper overestimates likely nitrate and 14C production from moderately nearby supernovae by about four orders of magnitude. Moreover, the results are based on wrongly selected (obsolete) nitrate and 14C datasets. The use of correct and up-to-date datasets does not confirm the claimed results. The claims in the paper are invalidated.