Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. (∼660 BC)

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: O’Hare, Paschal, Mekhaldi, Florian, Adolphi, Florian, Raisbeck, Grant, Aldahan, Ala, Anderberg, Emma, Beer, Jürg, Christl, Marcus, Fahrni, Simon, Synal, Hans-Arno, Park, Junghun, Possnert, Göran, Southon, John, Bard, Édouard, Muscheler, Raimund
• Other Authors: Department of Geology Lund, Lund University Lund, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Insitute of Aquatic Science and Technology Dübendorf (EAWAG), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Laboratory of Ion Beam Physics, Angström Laboratory, Uppsala University, Department of Earth System Science Irvine (ESS), University of California Irvine (UCI), University of California-University of California, Chaire Evolution du climat et de l'océan, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: solar storms; ice cores; solar proton events; radionuclides; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Greenland; Greenland ice cores; ice core
• Online Access: https://hal.archives-ouvertes.fr/hal-02476829; https://doi.org/10.1073/pnas.1815725116

International audience Recently, it has been confirmed that extreme solar proton events can lead to significantly increased atmospheric production rates of cosmogenic radionuclides. Evidence of such events is recorded in annually resolved natural archives, such as tree rings [carbon-14 (C-14)] and ice cores [beryllium-10 (Be-10), chlorine-36 (Cl-36)]. Here, we show evidence for an extreme solar event around 2,610 years B.P. (similar to 660 BC) based on high-resolution Be-10 data from two Greenland ice cores. Our conclusions are supported by modeled C-14 production rates for the same period. Using existing Cl-36 ice core data in conjunction with Be-10, we further show that this solar event was characterized by a very hard energy spectrum. These results indicate that the 2,610-years B.P. event was an order of magnitude stronger than any solar event recorded during the instrumental period and comparable with the solar proton event of AD 774/775, the largest solar event known to date. The results illustrate the importance of multiple ice core radionuclide measurements for the reliable identification of short-term production rate increases and the assessment of their origins.