Interstellar <mml:mmultiscripts>Fe 60 </mml:mmultiscripts> on the Surface of the Moon

A dying massive star ends in a supernova explosion ejecting a large fraction of its mass into the interstellar medium. If this happens nearby, part of the ejecta might end on Solar System bodies and, in fact, radioactive <mml:mmultiscripts>Fe 60 </mml:mmultiscripts> has been detected on the Pacific ocean floor in about 2 Ma old layers. Here, we report on the detection of this isotope also in lunar samples, originating presumably from the same event. The concentration of the cosmic ray produced isotope <mml:mmultiscripts>Mn 53 </mml:mmultiscripts> , measured in the same samples, proves the supernova origin of the <mml:mmultiscripts>Fe 60 </mml:mmultiscripts> . From the <mml:mmultiscripts>Fe 60 </mml:mmultiscripts> concentrations found we deduce a reliable value for the local interstellar fluence in the range of 1 ×10⁸ at /cm² . Thus, we obtain constraints on the recent and nearby supernova(e).