L. Decin 1, M. Cohen 2, K. Eriksson 3, B. Gustafsson 3, E. Huygen 1, P. Morris 4, B. Plez 3,5, J. Sauval 5, B. Vandenbussche 1,4, & C. Waelkens 1
1 Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200B, B-3000 Leuven, Belgium
2 Radio Astronomy Laboratory, 601 Campbell Hall, University of California, Berkeley, CAlifornia 94720
3 Astronomika observatoriet, Box 515, S-75120 Uppsala, Sweden
4 ISO Science Operation Center, Astrophysics Division, ESA, PO Box 50727, E-28080 Villafranca, Madrid, Spain
5 Atomspektroskopi, Fysika institution, Box 118, S-22100, Lund, Sweden
6 Observatoire Royal de Belgique, avenue Circulaire 3, B-1180 Bruxelles, Belgium
The interpretation of the ISO-SWS data requires an accurate calibration of the
spectrometers. This calibration is done with the help of observations of
standard candles. In the SWS spectral regions (2.38 to 45.2 
),
the primary standard candles are bright, mostly cool, stars. The better
these calibration sources are known in the infrared, the more accurate
the spectrometers will be calibrated. Because ISO offers the first opportunity
to observe in the infrared with a resolving power of
,
our
knowledge on stellar source - and for calibration more specifically stellar
atmospheres - is necessarily not so refined. A full exploitation of the
ISO data will therefore result from an iterative process, that should benefit
to both our understanding of the instrument and of the atmospheres of cool
stars. We report on the progree of a project whcih confronts SWS
observations of cool stars with state-of-art synthetic spectra
(Plez et al. 1992, AA 256, 551; Plez et al. 1993, ApJ 418, 812).
The ISO observations enable us to discriminate betwen various sources of
molecular data and put tight constraints on the atmospheric parameters
of the stellar templates. Preliminary results suggest that a 2% relative flux
accuracy may be attainable in bands 1 and 2 of the SWS range.