Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-08T07:25:32.678Z Has data issue: false hasContentIssue false
  • English
  • Français

A Study of the Interstellar Diffuse Absorption Features

Published online by Cambridge University Press:  14 August 2015

Chi-Chao Wu
Chi-Chao Wu*
Affiliation:
Space Astronomy Laboratory, Washburn Observatory, University of Wisconsin, Madison, Wis., U.S.A.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

At a resolution of 0.17 Å, the profile of λλ 5780, 5797 were found to be asymmetric and steeper to the blue. The FWHM of λ 5780 and λ 5797 are respectively 2.7 Å and 1.1 Å. There is also a broad, shallow feature shortward of λ 5780. Equivalent widths of λλ 5780, 5797 were measured at a resolution of 0.26 Å, and they present a very tight correlation. Therefore, it is highly likely that these two diffuse lines have a common origin. The correlation between the equivalent width of λ 5780, EW(λ 5780), and E(B – V) is good for normal field stars. But there is a systematic weakening of λ 5780 in the spectra of Be stars, and the reverse is true for stars in the Scorpius-Ophiucus region. Excluding Be stars, a least square fit gives EW(λ 5780) = 0.75 E(B – V) Å mag.–1. From the profiles and structures of the diffuse features, and the correlations with various parameters of the interstellar medium, it is suggested that: (1) the diffuse band λ 4430 may be produced by the preionization of H– and, (2) λλ 5780, 5797 may be due to the pure electronic transitions of the impurity centers in solid grains.

Type
Part II Diffuse Features
Information
Symposium - International Astronomical Union , Volume 52: Interstellar Dust and Related Topics , 1973 , pp. 91 - 95
Copyright
Copyright © Reidel 1973 

References

A'Hearn, M. F.: 1972, Astron. J. 77, 302.Google Scholar
Brück, M. T., Nandy, K., and Seddon, H.: 1969, Physica 41, 128.Google Scholar
Fano, U.: 1961, Phys. Rev. 124, 1866.CrossRefGoogle Scholar
Greenberg, J. M.: 1968, in Middlehurst, B. M. and Aller, L. H. (eds.), Nebulae and Interstellar Matter , U. of Chicago Press, Chicago, Chapter 6.Google Scholar
Greenberg, J. M.: 1971, Nature Phys. Sci. 230, 15.Google Scholar
Herbig, G. H.: 1967, in van Woerden, H. (ed.), ‘Radio Astronomy and the Galactic System’, IAU Symp. 31, 85.Google Scholar
Hulst, H. C. van de: 1957, Light Scattering by Small Particles , J. Wiley & Sons Inc., New York.Google Scholar
Ingemann-Hilberg, C. and Rudkj⊘bing, M.: 1970, Astrophys. Space Sci. 6, 101.Google Scholar
Johnson, F. M.: 1967, in Greenberg, J. M. and Roark, T. P. (eds.), Colloquium on Interstellar Grains , Rensselaer Polytechnic Institute, 1965, NASA, Washington, NASA SP-140, p. 241.Google Scholar
Nandy, K. and Seddon, H.: 1970, Nature 227, 264.Google Scholar
Rebane, K. K.: 1970, Impurity Spectra of Solids , Plenum Press, New York-London.Google Scholar
Rudkj⊘bing, M.: 1969a, Astrophys. Space Sci. 3, 102.Google Scholar
Rudkj⊘bing, M.: 1969b, Astrophys. Space Sci. 5, 68.Google Scholar
Rudkj⊘bing, M.: 1970, Astrophys. Space Sci. 6, 157.Google Scholar
Stoeckly, R. and Dressier, K.: 1964, Astrophys. J. 139, 240.Google Scholar
Wampler, E. J.: 1966, Astrophys. J. 144, 921.Google Scholar
Wickramasinghe, N. C. and Nandy, K.: 1970, Astrophys. Space Sci. 6, 154.Google Scholar
Wilson, R.: 1958, Astrophys. J. 128, 57.CrossRefGoogle Scholar
Wilson, R.: 1964, Publ. Roy. Obs. Edinburgh 4, 67.Google Scholar
Yen, W. M., Scott, W. C., and Schawlow, A. L.: 1964, Phys. Rev. 136, A271.Google Scholar