Astrophysics

, Volume 45, Issue 2, pp 131–142

Isotopic Composition and Abundance of Interstellar Neutral Helium Based on Direct Measurements

Authors

  • G. N. Zastenker
    • Institute for Space ResearchRussian Academy of Sciences
  • E. Salerno
    • Physics Institute of Bern University
  • F. Buehler
    • Physics Institute of Bern University
  • P. Bochsler
    • Physics Institute of Bern University
  • M. Bassi
    • Physics Institute of Bern University
  • Yu. N. Agafonov
    • Institute for Space ResearchRussian Academy of Sciences
  • N. A. Eismont
    • Institute for Space ResearchRussian Academy of Sciences
  • V. V. Khrapchenkov
    • Institute for Space ResearchRussian Academy of Sciences
  • H. Busemann
    • Physics Institute of Bern University
Article

DOI: 10.1023/A:1016057812964

Cite this article as:
Zastenker, G.N., Salerno, E., Buehler, F. et al. Astrophysics (2002) 45: 131. doi:10.1023/A:1016057812964

Abstract

One of the important problems in astrophysics is the determination of the abundances of the helium isotopes 3He and 4He in various regions of the universe, since those abundances can provide evidence of the intensities of various possible processes of the production and decay of light elements and can thereby reflect their history. In this paper we describe the procedure and results of the first determination by a direct method of the abundances of helium isotopes in the local interstellar medium surrounding the solar system. The experiment was carried out on the piloted MIR station by the prolonged exposure in open space of specimens of metallic foil with their subsequent return to earth and detailed laboratory mass-spectrometric analysis. As a result, we were able to obtain estimates of the 4He density (about 7.5·10-3 cm-3) and the 3He/4He isotopic ratio (about 1.7·10-4) for the local interst ellar medium.

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Copyright information

© Plenum Publishing Corporation 2002