| Abstract | We present VI CCD photometry of ~1990 stars in the central 6.35' x 6.35' region of the Leo II dwarf spheroidal galaxy, the second most distant among the known satellite galaxies of the Milky Way Galaxy. The color- magnitude diagrams of Leo II show a narrow red giant branch (RGB), a small number of asymptotic giant branch stars, and a strong concentration of red stars with V ~ 22 mag which consist of red horizontal branch, red giant clump, and/or RGB stars. The tip of the RGB is found to be at I_TRGB_= 17.7+/-0.2 mag and (V - I)_TRGB_ = 1.48+/-0.07 mag. From the I magnitude of the tip of the RGB, we estimate the distance modulus of Leo II to be (m - M)_0_ = 21.66+/-0.21 mag, corresponding to a distance of 215+/-20 kpc for an adopted zero extinction. We measure the mean color of the RGB at M_I_ = -3.5 mag (~0.5 mag fainter than the tip of the RGB) to be (V - I)_-3.5_ = 1.28+/-0.06 mag with an intrinsic dispersion of {DELTA}(V - I)_-3.5_ = 0.08 mag. From these values we estimate the mean metallicity of the RGB stars to be [Fe/H]= - 1.97+/-0.13 dex with a dispersion of ~0.3 dex. |
