Risks for life on habitable planets from superflares of their host stars

TL;DR

Superflares from host stars can significantly impact planetary evolution, potentially causing extinctions, aiding the origin of life, or threatening complex life, with risks that warrant further attention and caution.

Contribution

This paper analyzes the potential effects of superflares on planetary evolution, extinction events, and life's origins, highlighting the underestimated risks to habitable planets.

Findings

Superflares may drive extinction events on Earth and exoplanets.

Weaker superflares could facilitate the origin of life.

Superflares pose a significant threat to complex life on Mars and exoplanets.

Abstract

We explore some of the ramifications arising from superflares on the evolutionary history of Earth, other planets in the Solar system, and exoplanets. We propose that the most powerful superflares can serve as plausible drivers of extinction events, and that their periodicity could correspond to certain patterns in the terrestrial fossil diversity record. On the other hand, weaker superflares may play a positive role in enabling the origin of life through the formation of key organic compounds. Superflares could also prove to be quite detrimental to the evolution of complex life on present-day Mars and exoplanets in the habitable zone of M- and K-dwarfs. We conclude that the risk posed by superflares has not been sufficiently appreciated, and that humanity might potentially witness a superflare event in the next $\sim 10^3$ years leading to devastating economic and technological losses. In light of the many uncertainties and assumptions associated with our analysis, we recommend that these results should be viewed with due caution.