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 $UBV$ photometry of IC 10 from the Local Group Survey, obtaining $E(B-V)=0.52\pm 0.04$ mag. We derive the total reddening including the internal reddening, $E(B-V)=0.98\pm 0.06$ mag, using $UBV$ photometry of early-type stars in IC 10 and comparing $JHK_{ S}$ photometry of red giant branch stars in IC 10 and the SMC. Using the 2MASS 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]$_{ CG97}=-1.08\pm0.28$. The magnitude of the tip of the red giant branch (TRGB) of IC 10 in the $K_{ S}$ band is measured to be $K_{ S,TRGB}=18.28\pm0.01$. Based on the TRGB method, we estimate the distance modulus of IC 10 to be $(m-M)_{ 0}=24.27\pm0.03{ \rm (random)}\pm0.18{ \rm (systematic)}$, corresponding to the distance of $d=715\pm10\pm60$ kpc. This confirms that IC 10 is a member of the Local Group.
Categories: astro-ph.CO