Astrophysics and Space Science

, Volume 10, Issue 3, pp 383–392 | Cite as

On the spectrum of a gaseous nebula of pure hydrogen

III: The Balmer decrement
  • H. Gerola
  • M. Salem
  • N. Panagia


The Balmer decrement was calculated for a homogeneous, spherical, pure hydrogen nebula, ionised and excited both by radiative and collisional processes. Reabsorption in the Balmer series from sublevels 2s and 2p was taken into account. Calculations were carried out for electron temperatures of 104 K and 2×104 K, electron densities from 103 to 106 cm−3, and radii from 1015 to 1017 cm. The results define allowed and forbidden regions in the log(Hβ/Hγ) vs log(Hα/Hβ) diagram different from those of previous results obtained assuming purely radiative or purely collisional ionisation and excitation. A brief comparison with observations is presented and discussed.


Hydrogen Electron Temperature Pure Hydrogen Collisional Process Balmer Series 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Auer, L. H.: 1968,Astrophys. J. 153, 783.Google Scholar
  2. Avery, L. W., and House, L. L.: 1968,Astrophys. J. 152, 493.Google Scholar
  3. Burgess, A.: 1965,Mem. Roy. Astron. Soc. 69, 1.Google Scholar
  4. Capriotti, E.: 1964,Astrophys. J. 139, 225.Google Scholar
  5. Caputo, F., Gerola, H., and Panagia, N.: 1970,Astrophys. Letters 5, 275.Google Scholar
  6. Cox, D. P. and Matthews, W. G.: 1969,Astrophys. J. 155, 859.Google Scholar
  7. Flower, D. R.: 1969,Monthly Notices Roy. Astron. Soc. 146, 243Google Scholar
  8. Gerola, H. and Panagia, N.: 1968,Astrophys. Space Sci. 2, 285.Google Scholar
  9. Gerola, H. and Panagia, N.: 1970,Astrophys. Space Sci. 8, 120.Google Scholar
  10. Karzas, W. I. and Latter, R.: 1961,Astrophys. J. Suppl. Ser. 6, 167.Google Scholar
  11. Kuhi, L. Y.: 1968, inInterstellar Ionized Hydrogen (ed by Y. Terzian), W. A. Benjamin, New York.Google Scholar
  12. Mihalas, D.: 1967,Astrophys. J. 149, 169.Google Scholar
  13. O'Dell, C. R.: 1963,Astrophys. J. 138, 1018.Google Scholar
  14. O'Dell, C. R.: 1966,Astrophys. J. 145, 487.Google Scholar
  15. O'Dell, C. R.: 1967,Astrophys. J. 149, 373.Google Scholar
  16. Osterbrock, D. E.: 1962,Astrophys. J. 135, 195.Google Scholar
  17. Parker, R. A. R.: 1964,Astrophys. J. 139, 208.Google Scholar
  18. Seaton, M. J.: 1960, inReports on Progress in Physics,23, 317.Google Scholar
  19. Wampler, E. J.: 1968,Astrophys. J. 153, 19.Google Scholar

Copyright information

© D. Reidel Publishing Company 1971

Authors and Affiliations

  • H. Gerola
    • 1
  • M. Salem
    • 1
  • N. Panagia
    • 2
  1. 1.Departmento de Física, Facultad de Ciencias Exactas y NaturalesUniversidad de Buenos AiresBuenos AiresArgentine
  2. 2.Laboratorio di AstrofisicaFrascatiItaly

Personalised recommendations