- ID:
- ivo://CDS.VizieR/J/A+A/443/157
- Title:
- CCD photometry in 6 open clusters
- Short Name:
- J/A+A/443/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Within the sample of six young open clusters (NGC 1502, NGC 3105, Stock 16, NGC 6268, NGC 7235 and NGC 7510) we have investigated 1753 objects using the narrow band, three filter Delta a photometric system resulting in the detection of eleven bona-fide magnetic chemically peculiar (CP) stars and five Be or metal-weak stars. The results for the distant cluster NGC 3105 is most important because of the still unknown influence of the global metallicity gradient of the Milky Way. These findings confirms that CP stars are present in open clusters of very young ages (logt>=6.90) at galactocentric distances up to 11.4kpc. For all programme clusters the age, reddening and distance modulus were derived using the corresponding isochrones. Some additional variable stars within Stock 16 could be identified by comparing different photometric studies.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/107/277
- Title:
- CCD photometry of Abell clusters
- Short Name:
- J/A+AS/107/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/AJ/129/729
- Title:
- CCD photometry of luminous stars in M33
- Short Name:
- J/AJ/129/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its proximity and almost face-on inclination means that it projects over a large area on the sky, making it an ideal candidate for wide-field CCD mosaic imaging. Photometry was obtained for more than 106 stars covering a 74'x56' field centered on M33. Main-sequence, supergiant branch, red giant branch, and asymptotic giant branch (AGB) populations are identified and classified based on broadband V and I photometry. Narrowband filters are used to measure spectral features allowing, the AGB population to be further divided into C and M star types. The galactic structure of M33 is examined using star counts, color-color, and color-magnitude-selected stellar populations. We use the C to M star ratio to investigate the metallicity gradient in the disk of M33.
2194. CCD photometry of M60
- 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/PASP/127/31
- Title:
- CCD photometry of NGC 2482
- Short Name:
- J/PASP/127/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BV and u'g'r'i' CCD photometry of the central region of NGC 2482. We also present BVu'g' CCD photometry of five clusters that have been poorly studied in the past: Ruprecht 42, Ruprecht 51, Ruprecht 153, Ruprecht 154, and AH03 J0748-26.9, which to our knowledge has not been studied before. Using a global optimization technique that eliminates much of the subjectivity previously inherent in main-sequence fitting studies, we obtain values of the distances, ages, and metallicities of the clusters, with robust estimates of the uncertainties of these fundamental parameters. Four of our clusters are less than ~1.3kpc beyond the Sun's distance from the Galactic center and have essentially solar metallicity. The metallicities of those clusters more distant from the Galactic center are consistent with a 0.3dex step to lower [Fe/H] found in other studies.
- ID:
- ivo://CDS.VizieR/J/AJ/98/2086
- Title:
- CCD photometry of NGC 2257 RR Lyrae
- Short Name:
- J/AJ/98/2086
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B and V band CCD photometry is used to study 33 cluster and nine field RR Lyrae variables near the LMC cluster, NGC 2257. It is found that the mean magnitudes for the two groups differ by 0.17 mag. The cluster and field variables both have an Fe/H abundance ratio of -1.8+/-0.1. The results are compared used to compare NGC 2257 with galactic globular clusters, showing that NGC 2257 is indistinguishable from its local counterparts.
- ID:
- ivo://CDS.VizieR/J/AJ/106/181
- Title:
- CCD photometry of open cluster M67
- Short Name:
- J/AJ/106/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a CCD photometric survey of the central one-half degree of the old open cluster, M67, in U, B, V, and I colors to magnitude V=20. Extensive comparison of our photometry with other published datasets shows excellent agreement, indicating that CCD photometry is capable of producing a uniform set of measurements consistent with the photometric system defined primarily by the Landolt standard sequence. The color-magnitude diagram of the cluster shows a well-defined main sequence extending at least to the limit of the photometry at M(V)=10.55 and a substantial binary sequence. At least 38 percent of cluster stars are binaries. The observations were performed on 3 nights on 15-18 February 1990 with the 1.09m telescope at Kitt Peak National Observatory with a Tektronix 512^2^ CCD camera; a standard KPNO UBVRI filter set was used, with BVR filters being the Harris et, and I the "nearly Mould" filter.
- 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/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/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).
