Vivas, A. KatherinaA. KatherinaVivasWalker, Alistair R.Alistair R.WalkerMARTINEZ VAZQUEZ, CLARA EUGENIACLARA EUGENIAMARTINEZ VAZQUEZMONELLI, MatteoMatteoMONELLIBONO, GiuseppeGiuseppeBONODorta, AntonioAntonioDortaNidever, David L.David L.NideverFIORENTINO, GiulianaGiulianaFIORENTINOGallart, CarmeCarmeGallartAndreuzzi, G.G.AndreuzziBraga, Vittorio FrancescoVittorio FrancescoBragaDALL'ORA, MassimoMassimoDALL'ORAOlsen, KnutKnutOlsenStetson, Peter B.Peter B.Stetson2025-03-062025-03-0620200035-8711http://hdl.handle.net/20.500.12386/36459Time series observations of a single dithered field centred on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile, uniformly covering up to two half-light radii. Analysis of the g and I time series results in the identification and characterization of 130 periodic variable stars, including 98 RR Lyrae stars, 7 anomalous Cepheids, and 1 SX Phoenicis star belonging to the Crater II population, and 24 foreground variables of different types. Using the large number of ab-type RR Lyrae stars present in the galaxy, we obtained a distance modulus to Crater II of (m - M)<SUB>0</SUB> = 20.333 ± 0.004 (stat) ±0.07 (sys). The distribution of the RR Lyrae stars suggests an elliptical shape for Crater II, with an ellipticity of 0.24 and a position angle of 153°. From the RR Lyrae stars, we infer a small metallicity dispersion for the old population of Crater II of only 0.17 dex. There are hints that the most metal-poor stars in that narrow distribution have a wider distribution across the galaxy, while the slightly more metal-rich part of the population is more centrally concentrated. Given the features in the colour-magnitude diagram of Crater II, the anomalous Cepheids in this galaxy must have formed through a binary evolution channel of an old population.STAMPAenArticle10.1093/mnras/stz33932-s2.0-85079467690https://academic.oup.com/mnras/article/492/1/1061/5652202?login=falsehttps://api.elsevier.com/content/abstract/scopus_id/850794676902020MNRAS.492.1061VFIS/05 - ASTRONOMIA E ASTROFISICA