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Variations in the abundance of small particles

Published online by Cambridge University Press:  03 August 2017

F. Boulanger
F. Boulanger*
Affiliation:
Radioastronomie, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France

Abstract

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IRAS images of nearby molecular clouds show that the mid-IR emission from small particles in the size range 102 to 105 atoms is distributed very differently from the 100 μm emission from large dust grains. Variations in color ratios by as much as one order of magnitude are seen on all angular scales. We summarize observational properties of the color variations and argue that neither their large amplitude nor their morphology can be explained by changes of the excitation by the UV radiation field only. The color variations reflect considerable inhomogeneities in the abundance of small particles. We suggest that the abundance variations are related to the cycling of interstellar matter between the gas phase and dust grains. This interpretation entails that clouds with distinct IR colors differ in their density and velocity structure and that cycling of matter between gas phase and dust grains is more ubiquitous and rapid that generally thought.

Keywords

Molecular CloudsGrains : Size DistributionIR EmissionIRAS Colors
Type
Chemistry
Information
Symposium - International Astronomical Union , Volume 147: Fragmentation of Molecular Clouds and Star Formation , 1991 , pp. 151 - 160
Copyright
Copyright © Kluwer 1991 

References

Beichman, C., Wilson, R.W., Langer, W., and Goldsmith, P. 1988, Ap. J., 332, L81.Google Scholar
Bernard, J.P. 1990, Private Communication.Google Scholar
Boulanger, F., Baud, B., and van Albada, G.D. 1985, Astr. Ap. 144, L9 Google Scholar
Boulanger, F., and Pérault, M., 1988, Ap. J. 330, 964.Google Scholar
Boulanger, F., Falgarone, E., Helou, G., and Puget, J.L., 1989, in Interstellar Dust Contributed Papers, eds. Tielens, A.G.G.M. and Allamandola, L. J., NASA CP-3036.Google Scholar
Boulanger, F. 1989, The Physics and Chemistry of Interstellar Molecular Clouds, eds. Winnewisser, G. and Armstrong, J. T., Springer Verlag, p. 30 Google Scholar
Boulanger, F., Falgarone, E., Puget, J.L., and Helou, G. 1990, Ap. J. 364, 136 Google Scholar
Chlewicki, G., and Laureijs, R.J., 1988, Astr. Ap. 207, L11.Google Scholar
Désert, F.X., Boulanger, F., and Puget, J.L. 1990, Astr. Ap. 237, 215.Google Scholar
de Vries, C.P., and Le Poole, R.S. 1985, Astr. Ap., 145, L7.Google Scholar
Draine, B.T., and Salpeter, E.E. 1979, Ap. J. 231, 438.Google Scholar
Draine, B.T., and Anderson, N. 1985, Ap. J., 292, 494.Google Scholar
Duley, W.W. 1989, The Physics and Chemistry of Interstellar Molecular Clouds, eds. Winnewisser, G. and Armstrong, J.T., Springer Verlag, p. 353.Google Scholar
Falgarone, E. 1991, From Ground-based to Space-borne Submillimeter Astronomy, eds. Longdon, N. and Kaldeich, B., ESA Publ. Google Scholar
Heiles, C., Reach, W.T., and Koo, B.C., 1988, Ap. J. 332, 313.Google Scholar
Laureijs, R.J., Mattila, K., and Schnur, G. 1987, Astr. Ap. 184, 269.Google Scholar
Laureijs, R.J., Chlewicki, G., Clark, F.O., 1988. Astr. Ap. 192, L13.Google Scholar
Laureijs, R.J., Chlewicki, G., Clark, F.O., and Wesselius, P.R., 1989, Astr. Ap. 220, 226.Google Scholar
Laureijs, R.J. 1989, Ph. D. University of Groningen.Google Scholar
Laureijs, R.J., Clark, F.O., and Prusti, T. 1990, Ap. J. in press.Google Scholar
Leene, A. 1985, Astr. Ap., 154, 295.Google Scholar
Omont, A. 1986, Astr. Ap., 169, 159.Google Scholar
Puget, J.L., Léger, A., and Boulanger, F. 1985, Astr. Ap., 142, L19.Google Scholar
Puget, J.L. 1989, Interstellar Dust, eds. Allamandola, L. J. and Tielens, A.G.G.M., Kluwer, p. 119.CrossRefGoogle Scholar
Puget, J.L., and Léger, A., 1989, Ann. Rev. Astr. Ap., 27, 161.CrossRefGoogle Scholar
Tielens, A.G.G.M., and Allamandola, L.J. 1987, Interstellar Processes, eds. Hollenbach, D. and Thronson, R., Reidel, p. 397.Google Scholar
Weiland, J.L., Blitz, L., Dwek, E., Hauser, M.G., Magnani, L., and Rickard, L.J. 1986, Ap. J., 306, L101.CrossRefGoogle Scholar