Stromgren photometry of supergiants in the Magellanic clouds.

The first medium-band photometry of the less luminous yellow supergiants in the Magellanic Clouds is presented. The results permit a good estimation of the physical parameters of the stars, and form the basis for their detailed abundances to be derived through high-dispersion spectra. For more distant galaxies where even the brightest stars are too faint to measure spectroscopically, the index m1 from their Stromgren photometry offers the best hope for determining their metal abundances and hence the abundances of their local ISM. It is shown that theoretical colors must be derived for several different microturbulent velocities, covering the range important for supergiants, before this can be realized.