Related papers: RR Lyrae Variables in NGC 2808

In this paper we revisit observational data concerning RR Lyrae stars in Galactic globular clusters, presenting frequency histograms of fundamentalized periods for the 32 clusters having more than 12 pulsators with well recognized period…

We have calculated the physical parameters of the RR Lyrae stars in the globular cluster NGC~4147 via the Fourier decomposition of their light curves, using new data and well-established semi-empirical calibrations and zero points. The mean…

Globular clusters represent stellar laboratories where observations can be used to validate models of stellar evolution. In this study, we put forth new ultraviolet (UV) photometric results of stars in the Galactic globular cluster NGC…

CCD observations for 10 (6 previously known and 4 newly discovered) of the 11 RR Lyrae variables in NGC 5897 have been analysed. The period-luminosity and period-amplitude plots indicate that the population of RR Lyrae variables in NGC 5897…

We present time-series VI photometry of the metal-rich ([Fe/H] = -0.53) globular cluster NGC 6441. Our color-magnitude diagram shows that the extended blue horizontal branch seen in Hubble Space Telescope data exists in the outermost…

A rich harvest of RR Lyrae stars has been identified for the first time in B514, a metal-poor ([Fe/H] = 1.95 +/- 0.10 dex) globular cluster of the Andromeda galaxy (M31), based on Hubble Space Telescope Wide Field Planetary Camera 2 and…

We present UBVI photometry for about 60,000 stars in a region of 44'x33' centered on the Galactic globular cluster (GGC) NGC 2808. The central region has been mapped with the HST WFPC2 camera. We cover a field which extends from the center…

We present an analysis of \emph{VI} CCD time-series photometry of the Oo II type globular cluster M92. The variable star population of the cluster is studied with the aim of revising their classifications, identifications, frequency spectra…

We describe here results of a photometric time-sequence survey of the globular cluster M3 (NGC 5272), in a search for contact and detached eclipsing binary stars. We have discovered only one likely eclipsing binary and one SX Phe type star…

The outer-halo globular cluster NGC 6229 has a peculiar horizontal-branch (HB) morphology, with clear indications of a bimodal HB and a ``gap" on the blue HB. In this paper, we present extensive synthetic HB simulations to determine whether…

New BVI CCD photometry is presented for 60 RR Lyrae variables in the globular cluster M3. Light curves have been constructed and ephemerides have been (re)-derived for all of them. Four stars (i.e. V29, V136, V155 and V209), although…

We present a CCD $VI$ photometric study of the globular cluster M14. Particular attention is given to the variable stars. This allowed new classifications and cluster membership considerations. New variables are reported; 3 RRc, 18 SR and 1…

A five year CCD photometric \emph{VI} time-series of NGC 7006 is employed to perform a detailed analysis of the known population of variable stars. In the process we have corrected inconsistent classifications, sky coordinates and found ten…

We describe and summarize the findings from our CCD time-series photometry of globular clusters (GCs) program and the use of difference image analysis (DIA) in the extraction of very precise light curves even in the crowded central regions…

We have carried out a new photometric study of the remote Galactic globular cluster NGC 2419, using proprietary and archive B,V,I time-series CCD photometry of the cluster, that allowed us to discover a large number of new variable stars…

New observations of variable stars in the globular cluster M3 reveal that the RR Lyrae variable V79 is a double-mode (RRd) variable with the first overtone mode dominating. In all previous studies, V79 was found to be a fundamental mode…

We report on the discovery of a large number of RR Lyrae variable stars in the moderately metal-rich Galactic globular cluster M62 (NGC 6266), which places it among the top three most RR Lyrae-rich globular clusters known. Likely members of…

NGC 362 is a bright southern globular cluster for which no extensive variability survey has ever been done. Time-series CCD photometric observations have been obtained. Light curves have been derived with both profile fitting photometry and…

We present new multicolour CCD photometry of the central part of the globular cluster M3, mapping the precise position of ~120 RR Lyrae stars (RRab, RRd, RRc) on the horizontal branch (HB). The location of the double-mode variables (RRd) is…

We present a new, deep (V ~ 26) study of the Galactic globular cluster NGC 2419 based on B,V,I time-series CCD photometry over about 10 years and extending beyond the cluster published tidal radius. We have identified 101 variable stars of…