The Dyadic Radionuclide System 60Fe / 53Mn to Distinguish Interstellar from Interplanetary 60Fe

Dominik Koll,Ingo Leya,Thomas Faestermann,Silke Merchel,Anton Wallner,Gunther Korschinek,W Liu,Y Wang,S Zeng,X Tang,B Guo

doi:10.1051/epjconf/202226011022

Abstract

The discovery of live 60Fe in a deep-sea crust with proposed interstellar origin followed by evidence for elevated interplanetary 3He in the same crust raised the question on how to unambiguously identify the true production site of the identified 60Fe. Here, we show the implementation of the dyadic radionuclide system 60Fe / 53Mn to serve as a tool for the identification of surplus interstellar 60Fe over interplanetary production. The recent updates in experimental 60Fe and 53Mn data from iron meteorites as well as in production rate models confirm the validity and robustness of this dyadic system for future applications.

Highlights

Direct detection of freshly-synthesized supernova nuclides is one of the gold standards to study stars and their impact on the solar system
The first indication of live 60Fe in a deep-sea ferromanganese crust [3] followed by the clear discovery in a 2 Myr old layer [4] raised the question on its astrophysical origin
Elevated levels of 3He in the same crust were used as an argument to propose that the discovered 60Fe was produced by cosmic-ray spallation in meteorites and not by stars [5]

Summary

Introduction

Direct detection of freshly-synthesized supernova nuclides is one of the gold standards to study stars and their impact on the solar system. The proposed supernova (interstellar) origin [4] was subsequently challenged. The most viable candidates to establish cosmic-ray production rates of 60Fe are meteorites, which could be used to distinguish between a rather constant cosmic dust influx plus single large object events such as meteoroids, comets or asteroids and solitary supernova 60Fe influxes. It is critical to deduce the absolute amount of interplanetary dust influx into a sample This makes it challenging, because a constant background flux of 60Fe bearing cosmic dust modulated by single large events can mimic supernova influxes. For deep-sea crusts we integrate over several hundred thousand to millions of years, which makes rare events like meteorite falls even over global scales probable.

Cosmogenic 60Fe and 53Mn from meteorites

Interstellar 60Fe identification