Open Access

Laboratory simulation of space weathering: ESR measurements of nanophase metallic iron in laser-irradiated materials

  • Erika Kurahashi1Email author,
  • Chihiro Yamanaka2,
  • Keiko Nakamura3 and
  • Sho Sasaki1
Earth, Planets and Space201454:BF03352448

https://doi.org/10.1186/BF03352448

Received: 19 July 2002

Accepted: 14 November 2002

Published: 21 June 2014

Abstract

S-type asteroids are believed to be parent bodies of ordinary chondrites. However, the reflectance spectra of S-type asteroids are different from those of ordinary chondrites. This spectral mismatch is strongly considered as a result of space weathering, where high-velocity dust particle impacts should change the optical properties of the uppermost regolith surface of asteroids. To simulate space weathering by impact heating of dust particles, we irradiated nanosecond pulse laser beam onto planetary surface materials, whose pulse duration and energy rate are comparable with those of real dust impacts. The laser-irradiated samples show optical changes similar to that by space weathering, and contain nanophase metallic iron particles considered as the essential cause of space weathering. After laser-irradiations, we observed the samples by an Electron Spin Resonance (ESR) to perform quantitative analysis of nanophase metallic iron particles. We report the first description that the quantities of nanophase metallic iron particles in olivine samples increase at higher space weathering degree.