- ID:
- ivo://CDS.VizieR/J/ApJS/93/161
- Title:
- CCD photometry of 6 globular clusters
- Short Name:
- J/ApJS/93/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD photometry for six metal-rich Galactic globular clusters. The color-magnitude diagrams constructed from these data reach well below the horizontal branch (HB), all of which are predominantly redward of the instability strip. From these diagrams, we have measured the magnitude of the HB, the color of the red giant branch (RGB) at the level of the HB, and the magnitude difference between the HB and the RGB clump. Using these quantities, we are able to study the metallicities and reddenings of these clusters. We also discuss the color distribution of stars on the horizontal branch for these metal-rich systems and compare them with available data for putative field disk red HB stars. There appears to be a dearth of field red HB stars having [Fe/H]~-0.5 and B-V<0.85, which are plentiful in the clusters studied here.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/103/460
- Title:
- CCD photometry of M 71
- Short Name:
- J/AJ/103/460
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two sets of observations of the metal-rich globular cluster M 71 are presented. The first uses deep CCD exposures to derive a fiducial in V, B-V and compares this with a cluster of similar metallicity, 47 Tuc. Comparison with oxygen enhanced theoretical isochrones leads to age estimates for M 71 of from ~14+/-2Gyr to ~16+/-2Gyr. Within the limits imposed by the quality of the data, no significant age difference between the two clusters is found. The second set of 73 frames is used to search an overlapping 67"x104" area of the cluster for variable stars. Light curves and phase diagrams (where appropriate) are presented for all four of the variables discovered. One variable blue straggler (or SX Phe star) has been identified with a period of 0.050d. Values for its mass depend, of course, on the assumed pulsation mode-(0.90+/-0.47)M_{sun}_ for the first overtone mode, and (1.57+/-0.83)M_{sun}_ for the fundamental mode. One of the variables, with a 0.0582d period, but with a magnitude 1.75mag below the main sequence turnoff may be a field star. Two candidate eclipsing binary systems were also found. The most likely orbital period of one is 0.372d. This value, and the shape of the light curve, suggest that it could be a W UMa type variable. No period was obtainable for the other candidate binary due to a lack of phase coverage. Further data is needed to confirm and strengthen these claims, and to check for cluster membership.
- ID:
- ivo://CDS.VizieR/J/ApJ/682/135
- Title:
- CCD photometry of M60
- Short Name:
- J/ApJ/682/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of the globular clusters (GCs) in the giant elliptical galaxy M60 in the Virgo Cluster, based on deep, relatively wide field Washington CT_1_ CCD images. The CMD reveals a significant population of GCs in M60 and a large number of young luminous clusters in NGC 4647, a small companion spiral northwest of M60. The color distribution of the GCs in M60 is clearly bimodal, with a blue peak at (C-T_1_)=1.37 and a red peak at (C-T_1_)=1.87. We derive two new transformation relations between the (C-T_1_)_0_ color and [Fe/H] using the data for the GCs in our Galaxy and M49. Using these relations, we derive the metallicity distribution of the GCs in M60, which is also bimodal: a dominant metal-poor component with center at [Fe/H]=-1.2, and a weaker metal-rich component with center at [Fe/H]=-0.2. We estimate the total number of the GCs in M60 to be 3600+/-500 and the specific frequency to be S_N_=3.8+/-0.4.
- ID:
- ivo://CDS.VizieR/J/MNRAS/250/314
- Title:
- CCD photometry of omega Cen
- Short Name:
- J/MNRAS/250/314
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/110/1
- Title:
- CCD photometry of Pal 1
- Short Name:
- J/A+AS/110/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD photometry of the halo cluster Palomar 1 is presented in the Thuan-Gunn photometric system. The principal sequences of the color-magnitude diagrams are delineated in different spectral bands. The color- magnitude diagrams of the cluster show a well defined red horizontal branch, a subgiant branch and a main-sequence down to about two magnitudes below the main sequence turnoff. The giant branch is absent and the brightest stars are the horizontal branch stars. The age of the cluster determined by comparison with the isochrones of Bell & VandenBerg (1987ApJS...63..335B) is consistent with an age in the interval 12-14Gyr. A distance modulus of (m-M)_g0_=15.38+/-0.15 magnitude and E(g-r)=0.16 has been derived. An estimate of the cluster structural parameters such as core radius and concentration parameter gives r_c_=1.5pc and c=1.46. A mass estimate of 1.1x10^3^M_{sun}_ and a mass-to-light ratio of 1.79 have been obtained using King's (1966AJ.....71...64K) method. The morphology of color-magnitude diagrams allows Pal 1 to be interpreted as probably a globular cluster rather than an old open one. For a description of the uvgr photometric system, see e.g. <GCPD/38>
- ID:
- ivo://CDS.VizieR/J/AJ/112/618
- Title:
- CCD photometry of variable stars in M9
- Short Name:
- J/AJ/112/618
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD observations have been used to derive precise light curves for six of the previously known RR Lyrae variables in the Oosterhoff type II globular cluster M9 and to search for additional variables. Nine variables have been discovered, eight of the RR Lyrae type. As a result, the total number of RR Lyrae variables has been revised from 9 to 17 (9 RRc and 8 RRab), the mean period of the RRc stars has been revised from 0.341d to 0.342d and that of the RRab stars from 0.621d to 0.638d. Simon's method that relates physical properties of RRc stars to the pulsation period and Fourier phase parameter {phi}_31_ has been used to determine the mass, luminosity, and temperature for one of the RRc stars. Published observations of RR Lyrae stars in M15 have been used to test Simon's method (1993ApJ...410..526S, 1993, IAUCo, 139, 315) and the results are promising. The formulae of Jurcsik and Kovacs (1996A&A...312..111J) for relating Fourier parameters of RRab stars to [Fe/H] have been used to derive a metal abundance for M9.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/42.75
- Title:
- CCD RV light curve of M15 RR Lyrae
- Short Name:
- J/other/RMxAA/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of CCD photometry using V and R filters are reported for 33 RR Lyrae stars in M15. Applying the approach of Fourier decomposition of the light curves, the physical parameters of the type RRab and RRc variables were estimated. The cluster is Oosterhoff type II and the values for the iron content and distance are: [Fe/H]=-1.98+/-0.24 and d=8.67+/-0.41kpc, respectively. The mean values of the physical parameters determined for the RR Lyrae stars place the cluster precisely into the sequences Oosterhoff type - metallicity and metallicity - effective temperature, valid for globular clusters. Evidences of evolution from the ZAHB are found for the RRc but not for the RRab stars.
- ID:
- ivo://CDS.VizieR/J/AJ/116/2415
- Title:
- CCD UBVRI Photometry of M80
- Short Name:
- J/AJ/116/2415
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table photom.dat contains the first multicolour (UVBRI) CCD photometry of 4899 stars in a 4'x7' field of the poorly studied globular cluster M80. The observations were acquired on 1994 June 13-16 using the 2.5m telescope of the Las Campanas Observatory, with a 2x1024x1024 pixel CCD. Two observing 4'x4' fields were observed, the first one at the cluster center, and the second one centered at approximately 3' to the East of the cluster center. The limiting magnitude was deeper in the the second frame by approximately DV=2.5mag. The exposures were 8 to 500s, with a total of 7 frames in U, 17 frames in B, 20 frames in V, and 18 frames in I.
- ID:
- ivo://CDS.VizieR/J/ApJ/518/262
- Title:
- CCD VIc Photometry of M30 Stars
- Short Name:
- J/ApJ/518/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The file contains VIc data of the globular cluster M30. All frames were taken using a 2048x2048 pixel CCD with pixels covering 0.44 arcseconds on a side, for a total field of approximately 15 arcminutes on a side. Data were taken on 1994 July 78 at the Cerro Tololo Inter-American Observatory (CTIO) 4m telescope. The data were calibrated against Landolt (1983, Cat. <II/118>) standard stars.
- ID:
- ivo://CDS.VizieR/J/A+A/388/149
- Title:
- CCD Vilnius photometry of M56
- Short Name:
- J/A+A/388/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD observations of field stars in an area north-east of the globular cluster M 56 were obtained in six bands of the Vilnius photometric system. The data sets cover a field of 9'x9.5'. An outline of the data pathway from observations to reduction via IRAF is outlined in this text. Photometry of 366 stars brighter than 18th V magnitude has been obtained and the analysis of the observational errors is discussed.
