2009ApJ...703..816K

We estimate the reddening and distance of the nearest starburst galaxy IC 10 using deep near-infrared JHK_S photometry obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope. We estimate the foreground reddening toward IC 10 using the UBV photometry of IC 10 from the Local Group Survey, obtaining E(B - V) = 0.52±0.04 mag. We derive the total reddening including the internal reddening, E(B - V) = 0.98±0.06 mag, using the UBV photometry of early-type stars in IC 10 and comparing the JHK_S photometry of red giant branch stars in IC 10 and the Small Magellanic Cloud. Using the Two Micron All Sky Survey point-source catalog of 20 Galactic globular clusters, we derive a relation between the metallicity [Fe/H]_CG97 and the slope of the red giant branch in the K_S- (J - K_S) color-magnitude diagram. The mean metallicity of the red giant branch stars in IC 10 is estimated to be [Fe/H]_CG97= -1.08±0.28. The magnitude of the tip of the red giant branch (TRGB) of IC 10 in the K_S band is measured to be K_S,TRGB= 18.28 ±0.01. Based on the TRGB method, we estimate the distance modulus of IC 10 to be (m - M)₀= 24.27±0.03(random)±0.18(systematic), corresponding to the distance of d = 715±10±60 kpc. This confirms that IC 10 is a member of the Local Group.