Hostname: page-component-77c89778f8-5wvtr Total loading time: 0 Render date: 2024-07-16T22:30:58.050Z Has data issue: false hasContentIssue false
  • English
  • Français

Interstellar Dust and the H2 Molecule

Published online by Cambridge University Press:  08 February 2017

K. H. Schmidt
K. H. Schmidt*
Affiliation:
Jena Observatory, Jena, Germany

Extract

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.

Nearly 20 Years Ago van de Hulst stated that the formation of molecular hydrogen occurs on the surfaces of the interstellar grains. (See ref. 1.) In the last years several authors discussed the problem of the interstellar abundance of the H2 molecule. (See refs. 2 to 9.) They all found that the percentage of the molecular hydrogen in the interstellar gas probably is much larger than had been thought in the past and that the essential mechanism of H2 formation is the formation on the particle surfaces. Therefore, the formation rate of interstellar H2 is a function of the area of the grain surface per unit volume, which is dependent on the average radius of the grains ā, on the number of dust particles per unit volume N(ā), and on the distribution function of the particle radii. The formation rate is determined by the density of the atomic hydrogen nH and the temperature of the interstellar gas Tgas. Finally, the formation rate of H2 depends on the probability π that an impinging hydrogen atom on a grain joins with another hydrogen atom to form a molecule.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 7: Proper Motions , August 1965 , pp. 259 - 264
Copyright
Copyright © Kluwer Academic Publishers 1965

References

1. Van De Hulst, H. C.: The Solid Particles in Interstellar Space. Rech. Astron. Obs. Utrecht, vol. 11, pt. 2, 1949.Google Scholar
2. Takayanagi, K.; and Nishimura, S.: Possibility of Observing the 28μ Radiation from the Interstellar Hydrogen Molecules. Contr. Dept. Astron. Tokyo, no. 18, 1961.Google Scholar
3. Zwicky, F.: The Molecular-Hydrogen Content of the Universe. Astron. Soc. Pacific, Pub., vol. 71, 1959, p. 468.10.1086/127428CrossRefGoogle Scholar
4. Gold, T.: The Problem of the Abundance of the Hydrogen Molecule. Comm. Coll. Internat. Astrophys. Liège, vol. 10, 1961, p. 476.Google Scholar
5. McCrea, W. H.; and McNally, D.: The Formation of Population I Stars. Part II. The Formation of Molecular Hydrogen in Interstellar Matter. Roy. Astron. Soc, Monthly Notices, vol. 121, 1960, p. 238.10.1093/mnras/121.2.238CrossRefGoogle Scholar
6. Gould, R. J.: Interstellar Abundance of the Hydrogen Molecule. Astron. J., vol. 67. 1962, p. 115.10.1086/108640CrossRefGoogle Scholar
7. Gould, R. J.; and Salpeter, E. E.: The Interstellar Abundance of the Hydrogen Molecule I. Basic Processes. Astrophys. J., vol. 138, 1963, p. 393.10.1086/147654CrossRefGoogle Scholar
8. Gould, R. J.; Gold, T.; and Salpeter, E. E.: The Interstellar Abundance of the Hydrogen Molecule II. Galactic Abundance and Distribution. Astrophys. J., vol. 138, 1963, p. 408.10.1086/147655CrossRefGoogle Scholar
9. Lambrecht, H.; and Schmidt, K. H.: Zur Häufigkeit des Interstellaren H-Moleküls. Astron. Nachricht, vol. 288, 1964, p. 11.10.1002/asna.19652880104CrossRefGoogle Scholar
10. McDowell, M. R. C.: On the Formation of H2 in H I Regions. Observatory, vol. 81, 1961, pp. 240–243.Google Scholar
11. Dorschner, J.; Gürtler, J.; and Schmidt, K. H.: Zur Beschleunigung Senkrecht zur Galaktischen Ebene und zur Häufigkeit des Interstellaren H2-Moleküls. Astron. Nachricht, vol. 288, 1965, p. 149.10.1002/asna.19652880905CrossRefGoogle Scholar
12. Yasuda, H.: The Kinematics of High Velocity Stars and a Galactic Force, Kz, at a Larger Distance from the Galactic Plane. Ann. Tokyo Astron. Obs., ser. 2, vol. 7, 1961, p. 47.Google Scholar
13. Oort, J. H.: Note on the Determination of Kz and on the Mass Density Near the Sun. Bull. Astron. Inst. Netherlands, vol. 15, 1960, p. 45.Google Scholar
14. Lambrecht, H.; and Schmidt, K. H.: Über die Relative Häufigkeit Einiger Komponenten des Interstellaren Mediums. Mitt. Univ. Sternwarte Jena, no. 40, 1959.Google Scholar
15. Blaauw, A.: Interstellar Gas and Young Stars Near the Sun. The Distribution and Motion of Interstellar Matter in Galaxies (Woltjer, L., ed.), Benjamin, W. A., Inc. (New York), 1962.Google Scholar
16. Wood, B. J.; and Wise, H.: Diffusion and Heterogeneous Reaction II. Catalytic Activity of Solids for Hydrogen-Atom Recombination. J. Chem. Phys., vol. 29, 1958, p. 1416.10.1063/1.1744733CrossRefGoogle Scholar
17. Brackmann, R. T.; and Fite, W. L.: Condensation of Atomic and Molecular Hydrogen at Low Temperatures. J. Chem. Phys., vol. 34, 1961, p. 1572.10.1063/1.1701046CrossRefGoogle Scholar