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Gravitational instability of partially ionized molecular clouds

Published online by Cambridge University Press:  01 December 2007

A.C. BORAH
Affiliation:
Department of Physics, Assam University, Silchar 788011, India
A.K. SEN
Affiliation:
Department of Physics, Assam University, Silchar 788011, India

Abstract

Stars are formed as a result of the gravitational (Jeans) collapse of dense clumps in interstellar clouds. These clouds are partially ionized by nearby ionizing sources. We investigate the gravitational instability in such molecular clouds considering the non-Boltzmannian distribution for electrons and ions, which is more realistic than the Boltzmannian distribution. Assuming the perturbation (fluctuation) response in a radial direction as a mathematical analogue of the x-direction in the plane geometry approximation in the form f ∼ exp(ikxiωt), the equations of motion for different species of the multi-fluid plasma are linearized. Jeans' swindle is used as a local approximation for the equilibrium and the dispersion relation is derived by usual normal mode analysis. Then, an analytical solution to the dispersion equation with an explanation of the effects on star formation is given.

Type
Papers
Copyright
Copyright © Cambridge University Press 2007

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References

[1]Balsara, D. S. 1996 Astrophys. J. 465, 775794.Google Scholar
[2]Binney, J. and Tremaine, S. 1987 Galactic Dynamics. Princeton: Princeton University Press, p. 287.Google Scholar
[3]Bliokh, P., Sinitsin, V. and Yaroshenko, V. 1995 Dusty and Self-gravitational Plasmas in Space. Dordrecht: Kluwer.Google Scholar
[4]Dwivedi, C. B. 1997 Phys. Plasmas 4, 3427.Google Scholar
[5]Dwivedi, C. B., Sen, A. K. and Bujarborua, S. 1999 Astron. Astrophys. 345, 1049.Google Scholar
[6]Dwivedi, C. B., Tiwari, R. S., Sayal, V. K. and Sharma, S. R. 1989 J. Plasma Phys. 41, 219.CrossRefGoogle Scholar
[7]Goertz, C. K. and Ip, W. H. 1948 Geophys. Res. Lett. 11, 349.CrossRefGoogle Scholar
[8]Hazelton, R. C. and Yadlowsky, E. J. 1994 IEEE Trans. Plasma Sci. 22, 91.Google Scholar
[9]Jacobs, G. and Shukla, P. K. 2005 J. Plasma Phys. 71 (4), 487493.Google Scholar
[10]Jeans, J. H. 1920 Astronomy and Cosmogony, 2nd edn.Cambridge: Cambridge University Press.Google Scholar
[11]Kolb, E. W. and Turner, M. S. 1990 The Early Universe. Redwood City, CA: Addison-Wesley.Google Scholar
[12]Pandey, B. P., Avinash, K. and Dwivedi, C. B. 1994 Phy. Rev. E 49, 5599.Google Scholar
[13]Nakano, T., Hasegawa, T. and Norman, C. 1995 Astrophys. J. 450, 183.Google Scholar
[14]Shu, F. H., Tremaine, S., Adams, F. C. and Ruden, S. P. 1990 Astrophys. J. 358, 495.CrossRefGoogle Scholar
[15]Verheest, F. 2000 Waves in Dusty Space Plasmas. Dordrecht: Kluwer.CrossRefGoogle Scholar
[16]Walch, B., Horanyi, M. and Robertson, S. 1995 Phys. Lett. 75 (5), 838.CrossRefGoogle Scholar