Abstract
Monochromatic photographs in Hα, [Nii]λ 6584 and [Oiii]λ 5007 Å show many different details in the morphological structure of the Eskimo Nebula (NGC 2392). Hα and [Nii] images show, in a first approximation, similar structure (elliptical inner ring and broken outer ring) whereas both rings in [Oiii] are quite circular and regular in brightness. A photometric study using the method described by Louise (1974) gives various geometrical parameters of both rings which are practically the same for the observed lines. In other words, the classical stratification structure in planetary nebulae is not clearly observed in NGC 2392, in good agreement with previous observations (Wilson, 1950). This fact is probably a consequence of the peculiar structure in the geometry of the nebula. A model consisting of an inner toroid surrounded by a spherical shell is proposed to account for both photometric and spectroscopic observations.
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References
Aller, L. H.: 1956,Gaseous Nebulae, Chapman and Hall, London, p. 256.
Aller, L. H., Czyzak, S. J., and Kaler, J. B.: 1968,Astrophys. J. 151, 187.
Aller, L. H. and Keyes, C. D.: 1980,Astrophys. Space Sci. 72, 203.
Aller, L. H. and Liller, W.: 1968, inStars and Stellar Systems, Vol. 7, The University of Chicago Press, p. 562.
Aller, L. H. and Walker, M. F.: 1970,Astrophys. J. 161, 917.
Boeshaar, G. O.: 1974,Astrophys. J. 187, 283.
Buerger, E. G.: 1971, Thesis, Ohio State University.
Capriotti, E. R., Cromwell, R. H., and Williams, R. E.: 1971,Astrophys. Lett. 7, 241.
Carranza, G., Courtès, G., and Louise, R.: 1968,IAU Symp. 34, 249.
Czyzak, S. J. and Aller, L. H.: 1970,Astrophys. J. 162, 495.
Feibelman, W. A.: 1971,J. Roy. Astron. Soc. Can. 65, 25.
Flower, D. R.: 1969,Monthly Notices Roy. Astron. Soc. 146, 171.
Harmon, R. J. and Seaton, M. J.: 1966,Monthly Notices Roy. Astron. Soc. 132, 15.
Harrington, J. P.: 1969,Astrophys. J. 156, 903.
Hua, C. T. and Louise, R.: 1970,Astron. Astrophys. 9, 448.
Hua, C. T. and Louise, R.: 1972,Astron. Astrophys. 21, 193.
Hummer, D. G.: 1963,Monthly Notices Roy. Astron. Soc. 125, 461.
Hummer, D. G. and Seaton, M. J.: 1963,Monthly Notices Roy. Astron. Soc. 125, 437.
Hummer, D. G. and Seaton, M. J.: 1964,Monthly Notices Roy. Astron. Soc. 127, 217.
Kirkpatrick, R. C.: 1972,Astrophys. J. 176, 381.
Koppen, J.: 1979,Astron. Astrophys. Suppl. 35, 111.
Louise, R.: 1973,Mém. Soc. Roy. Sci. Liège 5, 465.
Louise, R.: 1974,Astron. Astrophys. 30, 189.
Minkowski, R. and Osterbrock, D. E.: 1960,Astrophys. J. 131, 537.
Osterbrock, D. E.: 1960,Astrophys. J. 131, 541.
Pottasch, S. R.: 1980,Astron. Astrophys. 89, 336.
Seaton, M. J.: 1954,Monthly Notices Roy. Astron. Soc. 114, 54.
Seaton, M. J.: 1966,Monthly Notices Roy. Astron. Soc. 132, 113.
Strömgren, B.: 1939,Astrophys. J. 89, 526.
Williams, R. E.: 1968,IAU Symp. 34, 190.
Williams, R. E.: 1970,Astrophys. J. 159, 829.
Wilson, O. C.: 1948,Astrophys. J. 108, 201.
Wilson, O. C.: 1950,Astrophys. J. 111, 279.
Wilson, O. C. and Aller, L. H.: 1951,Astrophys. J. 114, 421.
Wyse, A. B.: 1942,Astrophys. J. 95, 356.
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Louise, R. The structure of a typical double-ring planetary nebula NGC 2392. Astrophys Space Sci 79, 229–237 (1981). https://doi.org/10.1007/BF00655919
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DOI: https://doi.org/10.1007/BF00655919