EDP Sciences
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Volume 477, Number 2, January II 2008
Page(s) 543 - 545
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20078602

A&A 477, 543-545 (2008)
DOI: 10.1051/0004-6361:20078602

Physical conditions in CaFe interstellar clouds

P. Gnacinski and M. Krogulec

Institute of Theoretical Physics and Astrophysics, University of Gdansk, ul. Wita Stwosza 57, 80-952 Gdansk, Poland
    e-mail: pg@iftia.univ.gda.pl; fizmkr@univ.gda.pl

(Received 3 September 2007 / Accepted 25 October 2007)

Interstellar clouds that exhibit strong Ca I and Fe I lines are called CaFe clouds. Ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. We find that the chemical composition of CaFe clouds is solar and that there is no depletion into dust grains. CaFe clouds have high electron densities, $n_{\rm e}$$\approx$1 cm-3, that lead to high column densities of neutral Ca and Fe.

Key words: ISM: clouds -- ISM: abundances -- ISM: atoms -- ultraviolet: ISM

© ESO 2007