关键词: 金属丰度, 子结构, 恒星成分

Abstract:

Based on SDSS g,SDSS r,and SCUSS u photometry, we develop a photometric calibration for estimating the stellar metallicity from u－g and g－r colors by using the spectra of F- and G-type main-sequence stars. The rms scatter of the photometric metallicity residuals relative to spectrum-based metallicity is 0.14 dex when g－r<0.4, and 0.16 dex when g－r>0.4. Due to the deeper and more accurate magnitude of SCUSS u, we set the application of photometric metallicity estimation in the range of g<21. We select the Sagittarius (Sgr) stream stars in south Galactic cap to study metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinates of R~19 kpc and |Z|~14 kpc exhibits a more metal-rich distribution than the halo.

Key words: metallicity, substructure, stellar content