相关论文: BVI CCD Photometry of the Globular Cluster 47 Tuc

We used a set of archived HST/WFPC2 images to probe the stellar population in the core of the nearby Galactic Globular Cluster (GGC) 47 Tuc. From the ultraviolet (UV) Color Magnitude Diagrams (CMDs) obtained for ~4,000 stars detected within…

We present new B, V and I-band photometry for a sample of 43 local subdwarfs with HIPPARCOS parallax errors < 13%, in the metallicity range -1.0 < [Fe/H] < -0.3, which we use to perform main sequence (MS) fitting to the Galactic globular…

We have used high resolution WFPC2-HST and wide field ground-based observations to construct a catalog of blue straggler stars (BSS) in the globular cluster 47 Tuc spanning the entire radial extent of the cluster. The BSS distribution is…

Five fields located close to the center of the globular cluster NGC 104=47 Tuc were surveyed in a search for variable stars. We present V-band light curves for 42 variables. This sample includes 13 RR Lyr stars -- 12 of them belong to the…

We have used HST imaging of the central regions (R<100 arcsec, about 5 core radii) of the globular cluster 47 Tucanae to derive proper motions and U- and V-band magnitudes for 14,366 cluster members. We also present a catalogue of…

We present new BVI photometry of the globular cluster NGC 6981 (M72), based mostly on ground-based CCD archive images. We present a new color-magnitude diagram (CMD) that reaches almost four magnitudes below the turn-off level. We performed…

We have used ESO telescopes at La Silla and the Hubble Space Telescope (HST) in order to obtain accurate B,V,I CCD photometry for the stars located within 200" (~= 2 half-mass radii, r_h = 1.71') from the center of the cluster NGC 6101.…

Atmospheric parameters (effective temperature, surface gravity) and radial velocities are derived for 12 candidate blue horizontal branch (HB) stars in the globular clusters 47 Tuc and NGC 362, which so far have been known to contain…

Spectroscopic observations of binary stars in globular clusters are essential to shed light on the poorly constrained period, eccentricity, and mass ratio distributions and to develop an understanding of the formation of peculiar stellar…

We present wide-field BVI photometry for about 11,500 stars in the low-metallicity cluster NGC 5466. We have detected the red giant branch bump for the first time, although it is at least 0.2 mag fainter than expected relative to the…

Deep BV photometry for a large field covering the outer-halo globular cluster NGC 6229 is presented. For the first time, a colour-magnitude diagram (CMD) reaching below the main sequence turnoff has been obtained for this cluster. Previous…

We present a far-ultraviolet (FUV) study of the globular cluster M30 (NGC 7099). The images were obtained using the Advanced Camera for Surveys (ACS/SBC, F150LP, FUV) and the Wide Field Planetary Camera 2 (WFPC2, F300W, UV) which were both…

We report CCD photometric observations of the globular cluster NGC 5897, in the Johnson system filters B, V , R, and I. With the values for these magnitudes we obtain various colour indices and produce several colour-magnitude diagrams. We…

Blue stragglers (BSS) are stars whose position in the Color-Magnitude Diagram (CMD) places them above the main sequence turn-off (TO) point of a star cluster. Using data from the core of 47 Tuc in the ultraviolet (UV), we have identified…

We present far-UV spectroscopy obtained with HST for 48 blue objects in the core of 47 Tuc. Based on their position in a FUV-optical colour-magnitude diagram, these were expected to include cataclysmic variables (CVs), blue stragglers…

We present new $BVI$ photometry containing 40,000 stars of the Galactic globular cluster M15 (NGC 7078) covering a $25 \times 25$ arcminute area centered on the cluster with a magnitude range from the tip of the Red Giant Branch to three…

We combine ground and space-based photometry of the Galactic globular cluster 47 Tuc to measure four independent lines of evidence for a helium gradient in the cluster, whereby stars in the cluster outskirts would have a lower initial…

Positions of stars of 47 Tuc have been derived by the use of photographic plates and CCD frames (ESO La Silla) and data from the Hubble Space Telescope (HST). The positions have been determined with respect to the PPM, which is based on the…

We present 22 new (+3 confirmed) cataclysmic variables (CVs) in the non core-collapsed globular cluster 47 Tucanae (47 Tuc). The total number of CVs in the cluster is now 43, the largest sample in any globular cluster so far. For the…

We discuss the main properties of the Galactic globular cluster (GC) blue straggler stars (BSS), as inferred from our new catalog containing nearly 3000 BSS. The catalog has been extracted from the photometrically homogeneous V vs. (B-V)…