Cosmogenic 10 Be as a Tracer for Recent Heliospheric Encounters With Interstellar Cold Clouds and Nearby Supernovae

Abstract

Abstract Recent works suggest there are periods when the Sun encountered massive interstellar cold clouds which compressed the heliosphere to within Earth's orbit, exposing Earth to interstellar galactic cosmic rays and energetic particles of heliospheric origin. We model 10 Be production in Earth's atmosphere during possible interstellar cloud encounters and supernovae. We find that, if the heliosphere is compressed to 0.2 AU ( AU), the 10 Be production rate is elevated above the background. To be distinguished in marine sediments (iron‐manganese crusts) beyond terrestrial variability, this signal must be sustained for Myr ( Myr). A 0.7 AU ( AU) compression increases the 10 Be production rate above the background, which may be detectable if the event lasts Myr. We find that the 10 Be peak observed by Koll et al. (2025, https://doi.org/10.1038/s41467‐024‐55662‐4 ) 10 Ma is too prolonged to be produced by a supernova, but could be attributed to an interstellar cloud crossing.