Astrophysics and Space Science

, Volume 2, Issue 4, pp 510–519 | Cite as

Dust and atomic hydrogen nearρ Ophiuchi

  • P. Mészáros


We discuss the distribution of dust and atomic hydrogen in and around a small dark cloud nearρ Ophiuchi. Although the obscuration reaches values as high as 8 magnitudes, the values ofNH derived inside the cloud do not differ markedly from those found at nearby, less obscured points. At low values of the obscuration, dust and hydrogen isophotes show satisfactory agreement, i.e.,NH increases withNG. However, we find thatNH starts decreasing for sufficiently large values ofNG. In the entire range of optical extinctions investigated our observations are satisfied by an expression of the typeNH=ANG exp (-BNG). Interpretation of this relationship suggests that an appreciable part of the hydrogen has been converted to molecular form inside the cloud. A tentative method for calculating the time elapsed since the conversion process began is proposed.


Hydrogen Dust Atomic Hydrogen Entire Range Satisfactory Agreement 
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. Allen, C. W.: 1963,Astrophysical Quantities (2nd ed.), The Athlone Press, London, p. 252.Google Scholar
  2. Bok, B. J.: 1956,Astrophys. J. 61, 309.Google Scholar
  3. Bok, B. J., Lawrence, R. S., andMenon, T. K. 1955,Publ. Astron. Soc. Pacific 68, 249.Google Scholar
  4. Christiansen, W. N. andHindman, J. V.: 1952,Australian J. Sci. Res. A5, 437.Google Scholar
  5. Field, G. B., Rather, J. D. G., Aanestad, P. A., andOrszag, S. A. 1968,Astrophys. J. 151, 953.Google Scholar
  6. Field, G. B., Sommerville, W. B., andDressler, K. 1966,Ann. Rev. Astron. Astrophys. 4, 207.Google Scholar
  7. Garzoli, S. L. andVarsavsky, C. M. 1966,Astrophys. J. 145, 79.Google Scholar
  8. Gould, R. J. andSalpeter, E. E. 1963,Astrophys. J. 138, 408.Google Scholar
  9. Heeschen, D. S.: 1955,Astrophys. J. 121, 569.Google Scholar
  10. Heiles, C. E.: 1968,Astrophys. J. 151, 919.Google Scholar
  11. Khavtassi, D. Sh.: 1960,Atlas of Galactic Dark Nebulae, Tbilis.Google Scholar
  12. Knapp, H. F. P., Van den Meijdenberg, C. J. N., Beenakker, J. J. M., andVan de Hulst, H. C.: 1966,Bull. Astron. Inst. Neth. 18, 256.Google Scholar
  13. Lilley, A. E.: 1955,Astrophys. J. 121, 559.Google Scholar
  14. McCrea, W. H. andMcNally, D. 1960,Monthly Notices Roy. Astron. Soc. 121, 238.Google Scholar
  15. McGee, R. X., Murray, J. D., andMilton, J. A.: 1963,Australian J. Phys. 16, 136.Google Scholar
  16. Ross, F. E. andCalvert, M. R.: 1934–1936,Atlas of the Northern Milky Way, chart #5.Google Scholar
  17. Stecher, T. P. andWilliams, D. A. 1966,Astrophys. J. 146, 88.Google Scholar
  18. Stecher, T. P. andWilliams, D. A. 1967,Astrophys. J. (Letters) 149, L29.Google Scholar
  19. Van de Hulst, H. C., Muller, C. A., andOort, J. H.: 1954,Bull. Astron Inst. Neth. 12, No. 452, 117.Google Scholar
  20. Varsavsky, C. M.: 1968,Astrophys. J. 153, 627.Google Scholar

Copyright information

© D. Reidel Publishing Company 1968

Authors and Affiliations

  • P. Mészáros
    • 1
  1. 1.Instituto Argentino de RadioastronomíaBuenos AiresArgentina

Personalised recommendations