The distance to IC4499 from K-band photometry of 32 RR Lyrae stars

Abstract

Single epoch K-band photometry of 32 RR Lyrae stars in the young galactic globular cluster IC4499 is presented. The mean magnitudes have been estimated using the K-band template light-curves of Jones, Carney and Fulbright (1996). We derive an independent estimate of the distance and reddening for the cluster based on the new <Mk>-logP-[Fe/H] relation from Bono et al.(2003) which has a zero-point in agreement with the canonical LMC distance of (m-M)0 = 18.5. For an assumed metallicity of [Fe/H]=-1.65+-0.1 we find (m-M)0 = 16.47+-0.04+-0.06 (random and systematic errors respectively) and E(B-V)=0.24+-0.03 in good agreement with the findings of Walker and Nemec (1996) based on optical data. The distance estimate is very robust to uncertainties in the reddening estimate but naturally depends directly on the adopted zero-point of the <Mk>-logP-[Fe/H] relation.