- ID:
- ivo://CDS.VizieR/J/PASP/103/536
- Title:
- CCD Photometry of NGC 7142
- Short Name:
- J/PASP/103/536
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD B,V observations on the NGC 7142 (1950 position 21h44.7 +65d34') field reveal the presence of a single short-period variable star. The color-magnitude diagram of the field shows evidence for small-scale variable absorption across the face of the cluster. The age of NGC 7142 appears to be confirmed as intermediate between that of M67 and NGC 188, and a new distance-modulus is found to be (m-M)0 = 11.4 +/- 0.9
Number of results to display per page
Search Results
- 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/MNRAS/260/782
- Title:
- CCD photometry of NGC 2004 and 2100
- Short Name:
- J/MNRAS/260/782
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present results of CCD UBV photometry of stars in two young LMC clusters: NGC 2004 and 2100. A comparison of recent CCD investigations of these clusters shows large zero-point discrepancies.
- 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/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/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/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/112/2004
- 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).
- ID:
- ivo://CDS.VizieR/J/AJ/144/149
- Title:
- CCD photometry of the W UMa type TY Boo
- Short Name:
- J/AJ/144/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD four-color light curves of TY Boo made on eight nights over 2010-2011 were analyzed in comparison with historical light curves obtained from 1969 through 2011. The light curves could all be represented by a unique geometry and by wavelength consistent photometric parameters of a two-spot model on either stellar component. It is confirmed that TY Boo is a shallow W-type contact binary system with a degree of contact factor of f=7.6%(+/-0.8). A period investigation based on all available data shows a long-term decrease (dP/dt=-3.65x10^-8^days/yr) and an oscillation (P_3_=58.9yr, A=0.0254days). Without ruling out the presence of a tertiary companion, the weight of evidence points to an active cyclic magnetic activity that causes spot formation rather than an unseen companion. Mass transfer between the components and angular momentum loss are also considered as possible mechanisms.
- 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.
