- ID:
- ivo://CDS.VizieR/J/AJ/112/2004
- Title:
- CCD photometry of SMC cluster Kron 3
- Short Name:
- J/AJ/112/2004
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI CCD photometry of 3149 stars in the SMC populous cluster Kron 3. Radial dependence of the horizontal branch morphology has been revealed. Contrary to Rich et al. (1984ApJ...286..517R), we conclude that the cluster radius is about r=6'. We estimate the cluster metallicity as [Fe/H]=-1.26 and its apparent distance modulus as (m-M)=18.75mag. Our estimate of the cluster age, based on fitting isochrones of VandenBerg & Bell (1985ApJS...58..561V) to our V-(B-V) and V-(V-R) diagrams, is about 10Gyr, the lower limit being 8Gyr; this values is greater than those derived earlier, presumably partially due to the distance modulus values used by earlier investigators being too large. Our age estimate is not far from the upper values from Righ et al. (1984ApJ...286..517R).
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2122
- Title:
- CCD photometry of star clusters in the LMC
- Short Name:
- J/MNRAS/450/2122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Washington system colour-magnitude diagrams (CMDs) for 17 practically unstudied star clusters located in the bar as well as in the inner disc and outer regions of the Large Magellanic Cloud (LMC). Cluster sizes were estimated from star counts distributed throughout the entire observed fields. Based on the best fits of theoretical isochrones to the cleaned (C-T_1_, T_1_) CMDs, as well as on the {delta}T_1_ parameter and the standard giant branch method, we derive ages and metallicities for the cluster sample. Four objects are found to be intermediate-age clusters (1.8-2.5 Gyr), with [Fe/H] ranging from -0.66 to -0.84. With the exception of SL 263, a very young cluster (~16 Myr), the remaining 12 objects are aged between 0.32 and 0.89 Gyr, with their [Fe/H] values ranging from -0.19 to -0.50. We combined our results with those for other 231 clusters studied in a similar way using the Washington system. The resulting age-metallicity relationship shows a significant dispersion in metallicities, whatever age is considered. Although there seems to exist a clear tendency for the younger clusters to be more metal rich than the intermediate ones, we believe that none of the chemical evolution models currently available in the literature reasonably well represents the recent chemical enrichment processes in the LMC clusters. The present sample of 17 clusters is part of our ongoing project of generating a data base of LMC clusters homogeneously studied using the Washington photometric system and applying the same analysis procedure.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/407
- Title:
- CCD photometry & velocities of NGC 3680 stars
- Short Name:
- J/A+AS/118/407
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new CCD photometry in the b and y colours of the Stroemgren uvby system for 310 stars in a 13'x13' field centered on the intermediate-age open cluster NGC 3680. Careful cross-checks indicate that previously published BV photometry of NGC 3680 is affected by random and/or systematic errors precluding its use in critical comparison with theoretical isochrone computations. Detailed notes on several individual stars are given. In addition, we present =~400 new photoelectric radial-velocity observations of 109 stars obtained with the CORAVEL scanner during the period 1988-1994. These data allow substantially complete identification of member and non-member stars in the field, and of spectroscopic binaries in both groups. Rotational velocities have also been derived for the programme stars, and our velocity variability criteria for stars of all rotations are described. The further astrophysical discussion of the data, including the definition of radial-velocity membership criteria, theoretical isochrone fitting, and the dynamical state of the cluster and the origin of its "bimodal turnoff", will appear in a separate paper (Nordstroem et al. 1996).
- ID:
- ivo://CDS.VizieR/J/A+A/376/745
- Title:
- CCD standards for U and I in NGC 7790
- Short Name:
- J/A+A/376/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric U and I standard sequences in the field of the open cluster NGC 7790 are presented. The intention is to achieve wide ranges in magnitude and colour, making these sequences suitable for calibrating deep CCD photometry. The 84 standard stars extend the BVR sequences of Odewahn et al. (1992PASP..104..553O) to the near UV and IR, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/432/491
- Title:
- CCD UBVIc photometry of Pismis 8 and Pismis 13
- Short Name:
- J/A+A/432/491
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD UBVIc imaging photometry was carried out in the fields of the open clusters Pismis 8 and Pismis 13, located in the Vela-Puppis region in our Galaxy. MK spectral types have also been determined for a number of stars located in the fields of these two clusters which were used to secure membership among the brightest stars. Since our photometry goes to a fainter limit than previous studies we could provide better reddening, distance and age determinations. Both clusters are located close to the edge of the local arm in the third quadrant. Pismis 8 is a cluster about 5-7My old located at 2000pc from the Sun, while Pismis 13 was found at 2750pc with a probable age of about 100My. The estimate of the slopes of the mass functions in both cases yielded x=1.7 and x=2.1 for Pismis 8 and 13 respectively.
- ID:
- ivo://CDS.VizieR/J/other/NewA/12.461
- Title:
- CCD UBVIc photometry of Ruprecht 58
- Short Name:
- J/other/NewA/12.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a study that combines UBVI photometry, MK spectral classification and proper motions in the area of the, up to now unknown, open cluster Ruprecht 58 at the Puppis region.
- ID:
- ivo://CDS.VizieR/J/A+AS/114/1
- Title:
- CCD UBVI photometry of NGC 6791
- Short Name:
- J/A+AS/114/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Three new photometric CCD-based datasets are presented for NGC 6791. They consist of deep UBV photometry (to V_lim_=24, B_lim_=24, U_lim_=23) of the central parts of the cluster and of selected fields around it, and of relatively shallower UBVI photometry for the whole cluster (23'x23'). The data have been used to discuss the reddening, metallicity and age of NGC 6791.
- ID:
- ivo://CDS.VizieR/J/ApJ/576/880
- Title:
- CCD UBV photometry of h and {chi} Per
- Short Name:
- J/ApJ/576/880
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The h and chi Per "double cluster" is examined using wide-field (0.98x0.98{deg}) CCD UBV imaging supplemented by optical spectra of several hundred of the brightest stars. The UBV photometry was obtained from observations with the 0.9m telescope at Kitt Peak National Observatory using the Mosaic CCD camera (0.43arcsec/pix) on 1999 February 3. Conditions were photometric with a seeing about 1.3arcsec. The Mosaic camera consists of eight individual SITe 2048x4096 CCD chips arranged in two rows of four to produce a final image equivalent to 8192x8192 pixels (098x098{deg}) but with modest (35-50pix) gaps. Our imaging data set contains short (0.5s in V and B and 2s in U), medium (2s in V and B and 10s in U), and long (100s in V and B and 300s in U) integrations, each consisting of five dithered exposures that were combined to fill in gaps between the eight chips. Analyzing the data near the cluster nuclei results in identical reddenings E(B-V) (0.56+/-0.01), distance moduli (11.85+/-0.05), and ages (12.8+/-1.0Myr) for the two clusters. In addition, the initial mass function slope for each of the cluster nuclei is found to be quite normal for high-mass stars ({Gamma}=-1.3+/-0.2), indistinguishable from a Salpeter value. The masses of the two clusters are found to be 3700M_{sun}_ and 2800M_{sun}_ for h and {chi} when integrating the present-day mass function from 1 to 120M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1014
- Title:
- CCD UBVRIHa photometry in NGC 3603
- Short Name:
- J/AJ/127/1014
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRI and H{alpha} photometry of the extremely compact, starburst cluster NGC 3603. Ground-based images, Hubble Space Telescope (HST) archival data, as well as Chandra X-ray data have been used for this study. We present, for the first time, optical color-magnitude diagrams (CMDs) for the stars in the cluster core down to V=22mag. A well-defined main sequence (MS) as well as low-mass pre-main-sequence (PMS) stars can clearly be seen in the CMDs. This result confirms the finding by Eisenhauer et al. (1998ApJ...498..278E) that low-mass stars are forming in the starburst cluster. We also derive an age (1+/-1Myr) and distance of the cluster (V_0_-M_V_=14.2+/-0.2mag, i.e., d=6.9+/-0.6kpc).
- ID:
- ivo://CDS.VizieR/J/A+AS/122/9
- Title:
- CCD UBVRI Photometry of 4 open clusters
- Short Name:
- J/A+AS/122/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD observations in the U, B, V, R and I passbands have been used to generate colour-colour and deep colour-magnitude diagrams for the young open star clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087. The sample consists of about 2000 stars reaching down to V=20mag. The interstellar extinction across the face of the imaged cluster regions seems to be uniform with average values of E(B-V)=0.31, 0.34 and 0.22mag for NGC 4103, NGC 5662 and NGC 6087 respectively. The distances to the clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087 have been estimated as 0.5+/-0.05, 2.0+/-0.3, 0.8+/-0.1 and 1.0+/-0.1kpc respectively, while the corresponding ages estimated from the theoretical stellar evolutionary isochrones fitted to the bright proper motion cluster members are ~100, 30, 80 and 65Myr respectively. Present data are consistent with the membership of the Cepheid variable V Cen to NGC 5662 and of S Norm to NGC 6087. Heavy contamination by foreground and background field stars has unfortunately made it impossible to reach definite conclusions about the faint luminosity function, and the data do not reach faint enough limits to investigate pre-main sequence stars.