Astrophysics and Space Science

, Volume 79, Issue 2, pp 405–417 | Cite as

The 11.5 micrometer emission from carbon stars: Comparison with IR spectra of submicrometer-sized silicon carbide grains

  • C. Friedemann
  • J. Gürtler
  • Regina Schmidt
  • J. Dorschner


In this paper the results of an experimental investigation of the spectra of submicrometersized silicon carbide grains are presented. The grains manufactured from two types of commercial α-SiC were prepared according to the Jena IR spectroscopy program for particulates of cosmic importance. From the spectral records mass absorption coefficients have been derived. These data have been used to make a comparison of the laboratory spectra with the well-known 11.5 μm emission band observed in the spectra of carbon stars, which is probably due to a transition in circumstellar SiC grains. For this aim, a simple model of an optically thin circumstellar envelope containing SiC grains has been calculated. The theoretical profile of the 11.5 μm band derived by means of this model and based on the experimental mass absorption coefficients of SiC grains shows a striking similarity with the observed profile in the spectrum of the carbon star Y CVn. The total amount of SiC dust in the envelope of this star has been estimated at about 1024 g.


Dust Carbide Simple Model Experimental Investigation Emission Band 


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Copyright information

© D. Reidel Publishing Co 1981

Authors and Affiliations

  • C. Friedemann
    • 1
  • J. Gürtler
    • 1
  • Regina Schmidt
    • 1
  • J. Dorschner
    • 1
  1. 1.Universitäts-Sternwarte JenaGermany

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