Hostname: page-component-8448b6f56d-t5pn6 Total loading time: 0 Render date: 2024-04-23T09:48:48.500Z Has data issue: false hasContentIssue false

Magnetic braking and ambipolar diffusion in metal-poor protostars

Published online by Cambridge University Press:  01 November 2008

Hans Zinnecker*
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany email: hzinnecker@aip.de
Rights & Permissions [Opens in a new window]

Abstract

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.

In this short note, we raise the issue how magnetic braking of prestellar and protostellar condensations depends on the metallicity of the molecular gas cloud. We suggest that the degree of ionization, which determines the timescale for redistribution of magnetic flux (ambipolar diffusion) in the dense cloud core, depends linearly on the heavy element and dust abundance of the gas. This implies that magnetic braking is less efficient in metal-poor condensations, and hence more of the angular momentum problem of star formation must be solved by other means, such as fragmentation into (wider) binary systems. Observations of orbital periods (separations) of binary systems among the metal-poor Galactic halo stars could test this prediction.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2009

References

Basu, Sh. & Mouschovias, T.Ch. 1994, ApJ 432, 720CrossRefGoogle Scholar
Basu, Sh. & Mouschovias, T.Ch. 1995a, ApJ 452, 386Google Scholar
Basu, Sh. & Mouschovias, T.Ch. 1995b, ApJ 453, 271CrossRefGoogle Scholar
Ebert, R., v. Hoerner, S., & Temesvary, St. 1960, in: Die Entstehung von Sternen durch Kondensation diffuser Materie, Springer Verlag, pp. 290Google Scholar
Elmegreen, B. G. 1979, ApJ 232, 729CrossRefGoogle Scholar
Mestel, L. 1965, Quarterly Journal of the Royal Astronomical Society 6, 265Google Scholar
Mouschovias, T.Ch. 1977, ApJ 211, 147Google Scholar
Mouschovias, T.Ch. & Paleologou, E. V. 1979, ApJ 230, 204Google Scholar
Mouschovias, T.Ch. 1985, A&A 142, 41Google Scholar
Mouschovias, T.Ch. 1996, in: Solar and Astrophysical Magnetohydrodynamic Flows, eds. Tsinganos, K. C., Kluwer Academic Publishers, p. 505Google Scholar
Nakano, T. 1979, PASJ 31, 697Google Scholar
Ziegler, U. 2005, A&A 435, 385Google Scholar
Zinnecker, H., Köhler, R., & Jahreiß, H. 2004, RevMexAA 21, 33Google Scholar