We are pleased to acknowledge valuable input on flux calibration from Drs. Joris Blommaert and Alice Quillen. The referee, Dr. Marc Sauvage, is gratefully acknowledged for his careful reading of the first version of the paper and his continued advice on how to improve the data reduction: the paper has greatly benefited from his comments. Dr. Adam Burrows kindly made available to us new evolutionary tracks prior to publication. Dr. Jason Spyromilio is thanked for having allowed us to use part of his service observing time at the NTT. FC wishes to thank the staff of ESTEC and VILSPA for their support during Phase 2 data entry and data reduction, as well as the staff of ESO at La Silla for their assistance during observations. Special thanks go to the astronomer in charge of service observing at the NTT when our observations were done. This work has been supported by Collaborative Research Grants Programme of NATO (CRG 940671), by NASA grants NAGW-4083 and NAG5-3359, and by the CICYT under contract ESP97-1803. The ISOCAM data presented in this paper were analysed using "CIA", a joint development by the ESA Astrophysics Division and the ISOCAM Consortium led by the ISOCAM PI, C. Cesarsky, Direction des Sciences de la Matiere, C.E.A., France.
© European Southern Observatory (ESO) 1998
Online publication: June 18, 1998