%0 Journal Article %T Variable stars in local group galaxies - IV. RR Lyrae stars in the central regions of the low-density galaxy Crater II %+ Observatoire de la Côte d'Azur (OCA) %A Monelli, M. %A Walker, A. R. %A Martínez-Vázquez, C. E. %A Stetson, P. B. %A Gallart, C. %A Bernard, E. J. %A Bono, G. %A Vivas, A. K. %A Andreuzzi, G. %A Dall'Ora, M. %A Fiorentino, G. %A Dorta, A. %< avec comité de lecture %@ 0035-8711 %J Monthly Notices of the Royal Astronomical Society %I Oxford University Press (OUP): Policy P - Oxford Open Option A %V 479 %P 4279-4291 %8 2018 %D 2018 %Z 1806.08595 %Z 2018MNRAS.479.4279M %R 10.1093/mnras/sty1645 %K stars: general %K stars: horizontal branch %K stars: variables: RR Lyrae %K galaxies: evolution %K Local Group %K Astrophysics - Astrophysics of Galaxies %Z Sciences of the Universe [physics] %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]Journal articles %X We present a search and analysis of variable stars in the recently discovered Crater II dwarf galaxy. Based on B, V, I data collected with the Isaac Newton Telescope (FoV∼0.44 deg2), we detected 37 variable stars, of which 34 are bone-fide RR Lyrae stars of Crater II (28 RRab, 4 RRc, 2 RRd). We applied the metal-independent (V, B - V) Period-Wesenheit relation and derived a true distance modulus (μ = 20.30 ± 0.08 mag (σ = 0.16 mag). Individual metallicities for RR Lyrae stars were derived by inversion of the predicted I-band Period-Luminosity relation. We find a mean metallicity of [Fe/H] = -1.64 and a standard deviation of σ _{[Fe/H]}=0.21 dex, compatible with either negligible or vanishing intrinsic metallicity dispersion. The analysis of the colour-magnitude diagram reveals a stark paucity of blue horizontal branch stars, at odds with other Galactic dwarfs, and globular clusters with similar metal abundances. %G English %2 https://insu.hal.science/insu-03689234/document %2 https://insu.hal.science/insu-03689234/file/sty1645.pdf %L insu-03689234 %U https://insu.hal.science/insu-03689234 %~ INSU %~ CNRS %~ OCA %~ UNIV-COTEDAZUR