Decin, L. ; Vandenbussche, B. ; Waelkens, C. ; Decin, G. ; Eriksson, K. ; Gustafsson, B. ; Plez, B. ; Sauval, A. J.

published in Astronomy and Astrophysics, 400, pp. 709-727 (2003)

Abstract: A detailed spectroscopic study of 11 giants with spectral type from G9 to M2 is presented. The 2.38-4.08 mu m wavelength-range of band 1 of ISO-SWS (Short-Wavelength Spectrometers on board of the Infrared Space Observatory) in which many different molecules - with their own dependence on each of the stellar parameters - are absorbing, enables us to estimate the effective temperature, the gravity, the microturbulence, the metallicity, the CNO-abundances, the 12C/13C-ratio and the angular diameter from the ISO-SWS data. Using the Hipparcos' parallax, the radius, luminosity and gravity-inferred mass are derived. The stellar parameters obtained are in good agreement with other published values, though also some discrepancies with values deduced by other authors are noted. For a few stars (delta Dra, xi Dra, alpha Tuc, H Sco and alpha Cet) some parameters - e.g. the CNO-abundances - are derived for the first time. By examining the correspondence between different ISO-SWS observations of the same object and between the ISO-SWS data and the corresponding synthetic spectrum, it is shown that the relative accuracy of ISO-SWS in band 1 (2.38-4.08 mu m) is better than 2% for these high-flux sources. The high level of correspondence between observations and theoretical predictions, together with a confrontation of the estimated Teff (ISO) value with Teff values derived from colours - which demonstrates the consistency between V-K, BCK, Teff and thetad derived from optical or IR data - proves that both the used MARCS models to derive the stellar quantities and the flux calibration of the ISO-SWS detectors have reached a high level of reliability. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA. Appendices A-D are only available in electronic form at http://www.edpsciences.org

DOI: 10.1051/0004-6361:20021786
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