Bj. Anthonytwarog et Ba. Twarog, CA-II H-PHOTOMETRY AND K-PHOTOMETRY ON THE UVBY SYSTEM - III - THE METALLICITY CALIBRATION FOR THE RED GIANTS, The Astronomical journal (New York), 116(4), 1998, pp. 1922-1932
New photometry on the uvby Ca system is presented for over 300 stars.
When combined with previous data, the sample is used to calibrate the
metallicity dependence of the hk index for cooler, evolved stars. The
metallicity scale is based upon the standardized merger of spectroscop
ic abundances from 38 studies since 1983, providing an overlap of 122
evolved stars with the photometric catalog. The hk index produces reli
able abundances for stars in the [Fe/H] range from -0.8 to -3.4, losin
g sensitivity among cooler stars due to saturation effects at higher [
Fe/H], as expected.