🗂️ Cosmology & Space · View mindmap

Iron-60

Iron-60 (${}^{60}\text{Fe}$) is a long-lived radioactive isotope of iron with a half-life of approximately 2.6 million years. It is primarily produced in massive stars during nucleosynthesis and expelled via supernovae or Asymptotic Giant Branch star winds.

Detection and Significance

• Paleo-record Proxy: ${}^{60}\text{Fe}$ serves as a key tracer for recent near-Earth supernovae events, as it is not produced significantly by cosmic rays in Earth’s atmosphere.
• Ice Core Analysis: Recent studies of Antarctic Ice cores have detected anomalies in ${}^{60}\text{Fe}$ concentrations.
  • See analysis: Antarctic Ice Fe-60: Solar System’s Entry into Local Interstellar Cloud
  • Evidence suggests a correlation between ${}^{60}\text{Fe}$ deposition and the Solar System’s traversal into the Local Interstellar Cloud.

Astrophysical Context

• Galactic Origin: ${}^{60}\text{Fe}$ indicates interaction with the Interstellar Medium (ISM), specifically dust grains from nearby stellar remnants.
• Timeline: Elevated levels observed in deep-sea sediments and ice cores typically date back to the last few million years, aligning with models of the Solar System’s exit from the Local Bubble and entry into denser interstellar clouds.
• Isotope Ratio: Combined analysis with ${}^{26}\text{Al}$ helps distinguish between supernova injection and spallation background.