We present B,V and I CCD light curves for 101 variable stars belonging to the globular cluster NGCÂ 2419 , 60 of which are new discoveries , based on datasets obtained at the TNG , SUBARU and HST telescopes .
The sample includes 75 RR Lyrae stars ( of which 38 RRab , 36 RRc and one RRd ) , one Population II Cepheid , 12 SX Phoenicis variables , 2 \delta Scuti stars , 3 binary systems , 5 long-period variables , and 3 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 hypotesis for the origin of NGCÂ 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 } ( NGCÂ 2419 ) = 19.71 \pm 0.08 mag ( D= 87.5 \pm 3.3 kpc ) , with E ( B - V ) = 0.08 \pm 0.01 mag , [ Fe/H ] = - 2.1 dex in the Zinn & West metallicity scale , and a value of M _ { V } that sets \mu _ { 0 } ( LMC ) = 18.52 mag .
This value is in good agreement with most recent literature estimates of the distance to NGCÂ 2419 .