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Graphite and Interstellar Extinction1

Published online by Cambridge University Press:  08 February 2017

T. P. Stecher
Affiliation:
NASA Goddard Space Flight Center Greenbelt, Maryland
Bertram Donn
Affiliation:
NASA Goddard Space Flight Center Greenbelt, Maryland

Extract

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The Theory That Graphite Particles could be responsible for interstellar extinction is presented in references 1 and 2, and this paper will present evidence that further supports this contention. The complex dielectric constant (m = n(l — ik) for graphite has been measured as a function of energy by the authors of reference 3, and the optical constants as function of wavelength λ have been obtained from this measurement. A large variation occurs in both n and k at wavelengths below 3000 Å.

The results reported in the preceding paper indicated the desirability of performing Mie scattering calculations on graphite. The measured values of the complex index of refraction corresponding to 17 wavelengths were used in the calculation for spherical particles. The IBM 7094 computer program for Mie scattering follows that of van de Hulst. (See ref. 4.) The Oort-van de Hulst size distribution (ref. 5), which may not be applicable to the type of particle discussed herein, has been used to obtain an integrated cross section for extinction.

Type
Research Article
Copyright
Copyright © Kluwer Academic Publishers 1965

Footnotes

1

The contents of this paper were published previously in the Astrophys. J. (pub. by the Univ. of Chicago Press), vol. 142, 1965, p. 1681

References

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