... envelopes

Appendices are only available in electronic form at http://www.edpsciences.org

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...

Present address: Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany.

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... CO

The CO lines are optically thick and, therefore, the cooling function does not depend on the CO abundance unless it decreases by a factor of 100 with respect to the standard value.

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