INFRARED STANDARDS FOR ISO - I - A NEW CALIBRATION OF MID INFRARED PHOTOMETRY

We present N, 8.7 mu m, 9.8 mu m 12.5 mu m and Q bolometry of 26 stars which were observed on the IRTF. These are primarily K giants which h ave been well measured at other wavelengths and are chosen to be singl e and non-variable. Hence the data presented provides a new homogeneou s set of mid IR standards. As a test of part of the calibration strate gy of ISO over this wavelength range, the zero points have been set us ing the Kurucz model grids (1993) to predict the mid IR. magnitudes fr om near IR data. An analysis of the errors involved is presented and a comparison with more direct methods for the determination of the zero points suggest an possible error of 0.015 mags, although the source o f this error is unclear as it is at the level of the uncertainty in th e more direct methods. The effect of the SiO fundamental on the spectr al energy distributions of K giants is discussed.