Letter to the Editor

The late Miocene ¹⁰Be anomaly and the possibility of a supernova

¹ University of Vienna, Department of Astrophysics, Türkenschanzstraße 17, 1180 Wien, Austria
² Astronomical Institute of the Czech Academy of Sciences, Boční II 1401, 141 31 Prague 4, Czech Republic
³ Center for Astrophysics | Harvard & Smithsonian, 60 Garden St., Cambridge, MA 02138, USA

^⋆ Corresponding author: efrem.maconi@univie.ac.at

Received: 4 July 2025
Accepted: 1 September 2025

Abstract

Recent measurements of cosmogenic ¹⁰Be in deep-ocean ferromanganese crusts from the central and northern Pacific have revealed an anomalous concentration between 11.5 and 9.0 Myr ago, peaking at 10.1 Myr. One possible explanation is a nearby supernova (SN) event. Motivated by this and by the proximity of the Solar System to the Orion star-forming region during that period, we estimated the probability that at least one SN occurred between the onset and peak of the anomaly. Using an open cluster catalog based on Gaia DR3, we traced back the orbits of 2725 clusters and the Sun over the past 20 Myr and computed the expected number of SN events. We found 19 clusters with a probability greater than 1% each of producing at least one SN within 100 pc of the Sun in the time interval 11.5–10.1 Myr ago. The total cumulative probability exceeds zero at 35 pc from the Sun and increases rapidly with distance, reaching 68% near 100 pc. Two young clusters dominate the SN probability: ASCC 20 contributes most within 70 pc, while OCSN 61 becomes more significant beyond that distance. Our results support the possibility of an SN origin for the ¹⁰Be anomaly and highlight the importance of additional ¹⁰Be records from independent terrestrial archives to determine whether the anomaly is of astrophysical or terrestrial origin.