A NEW CENSUS OF THE VARIABLE STAR POPULATION IN THE GLOBULAR CLUSTER NGC 2419

作者：Di Criscienzo M^*; Greco C; Ripepi V; Clementini G; Ora M Dall'; Marconi M; Musella I; Federici L; Di Fabrizio L

来源：Astronomical Journal, 2011, 141(3): 81.

DOI：10.1088/0004-6256/141/3/81

• Galaxy: halo
• globular clusters: general
• globular clusters: individual (NGC 2419)
• stars: horizontal-branch
• stars: variables: general
• techniques: photometric

We present B, V, and I CCD light curves for 101 variable stars belonging to the globular cluster NGC 2419, 60 of which are new discoveries, based on data sets obtained at the Telescopio Nazionale Galileo, the Subaru telescope, and the Hubble Space Telescope. The sample includes 75 RR Lyrae stars (38 RRab, 36 RRc, and one RRd), one Population II Cepheid, 12 SX Phoenicis variables, two delta Scuti stars, three binary systems, five long-period variables, and three variables of uncertain classification. The pulsation properties of the RR Lyrae variables are close to those of Oosterhoff type II clusters, consistent with the low metal abundance and the cluster horizontal branch morphology, disfavoring ( but not totally ruling out) an extragalactic hypothesis for the origin of NGC 2419. The observed properties of RR Lyrae and SX Phoenicis stars are used to estimate the cluster reddening and distance, using a number of different methods. Our final value is mu(0) (NGC 2419) = 19.71 +/- 0.08 mag ( D = 87.5 +/- 3.3 kpc), with E(B-V) = 0.08 +/- 0.01 mag, [Fe/H] = - 2.1 dex on the Zinn & West metallicity scale, and a value of MV that sets mu(0) (LMC) =

• 出版日期2011-3