CALIBRATIONS OF M-UPSILON, [FE H], AND LOG-G FOR YELLOW SUPERGIANT STARS FROM O I-7774 AND U-UPSILON-BY-BETA-DATA/

New calibrations of the absolute magnitude M(v) from O I 7774 data are derived from narrow-band photometry and low dispersion spectroscopy f or A0-G2 low and high luminosity stars. The nonlinear dependence of M( v) from the equivalent width W(O I) and the relevance of the stellar t emperature in the calibration are confirmed in agreement with previous calibrations obtained from high resolution spectroscopy. Also functio nal formulas to estimate [Fe/H] and log g from uvbybeta data for F0-G3 supergiants are offered. These calibrations predict iron abundances. and gravities for yellow supergiants with uncertainties not much highe r than good spectroscopic determinations.