- 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/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.
- ID:
- ivo://CDS.VizieR/J/AJ/143/30
- Title:
- CCD photometry of V380 Cas
- Short Name:
- J/AJ/143/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multicolor CCD photometry for the eclipsing binary V380 Cassiopeia (V380 Cas) observed on 34 nights in 2009 and 2010 at the University of Patras Observatory. The PHOEBE program based on the Wilson-Devinney algorithm was used to analyze the first complete BVRcIc light curves. It was found that V380 Cas was misclassified and it is a well-detached system consisting of two main-sequence stars. A range of solutions found to give satisfactory fits to the observations is also investigated. The first orbital solution based on the photometric mass ratio q=1.08 of almost equal temperatures and masses and orbital inclination of i=86.57{deg} was obtained. In addition, based on all available times of light minima, including 12 new ones, a new orbital period of P=2.714539884 days is given.
- ID:
- ivo://CDS.VizieR/J/AJ/155/58
- Title:
- 2006-2016 CCD photometry of V723 Cassiopeia
- Short Name:
- J/AJ/155/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric data of the classical nova, V723 Cas (Nova Cas 1995), over a span of 10 years (2006 through 2016) taken with the 0.9 m telescope at Lowell Observatory, operated as the National Undergraduate Research Observatory (NURO) on Anderson Mesa near Flagstaff, Arizona. A photometric analysis of the data produced light curves in the optical bands (Bessel B, V, and R filters). The data analyzed here reveal an asymmetric light curve (steep rise to maximum, followed by a slow decline to minimum), the overall structure of which exhibits pronounced evolution including a decrease in magnitude from year to year, at the rate of ~0.15 mag/yr. We model these data with an irradiated secondary and an accretion disk with a hot spot using the eclipsing binary modeling program Nightfall. We find that we can model reasonably well each season of observation by changing very few parameters. The longitude of the hot spot on the disk and the brightness of the irradiated spot on the companion are largely responsible for the majority of the observed changes in the light curve shape and amplitude until 2009. After that, a decrease in the temperature of the white dwarf is required to model the observed light curves. This is supported by Swift/X-Ray Telescope observations, which indicate that nuclear fusion has ceased, and that V723 Cas is no longer detectable in the X-ray.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/337
- Title:
- CCD photometry of YY Orionis stars
- Short Name:
- J/A+AS/129/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of photometric monitoring in the UBVRI bands of 5 YY Orionis stars and 2 other variable stars are presented. Each source was observed in the period of 1996, Nov. 23 to Dec. 2 and of 1996, Dec. 23 to 1997,Jan. 2 at the 1-m telescope of Wise Observatory, Israel. Tables.dat contain the luminosity variation of each star as deviation from its average observed magnitude.
- 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/PAZh/27/403
- Title:
- CCD R photometry in the UMa supercluster
- Short Name:
- J/PAZh/27/403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric parameters for 98 early-type galaxies in the central for 11 clusters, belonging to the Ursa Major supercluster, are presented. Galaxies in the following clusters have been observed: A1270, A1291, A1377, A1318, A1383, A1436, Anon1, Anon2, Anon3, Anon4, Sh166. The derivation of the effective parameters takes the seeing into account.
- ID:
- ivo://CDS.VizieR/J/A+A/382/389
- Title:
- CCD R photometry of 17 clusters of galaxies
- Short Name:
- J/A+A/382/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of streaming motion of galaxy clusters around the Giant Void (RA~13h, DE~40{deg}, z~0.11 and a diameter of 150/hMpc) in the distribution of rich Abell clusters. We used the Kormendy relation as a distance indicator taking into account galaxy luminosities. Observations were carried out in Kron-Cousins R_c_ system on the 6m and 1m telescopes of SAO RAS. For 17 clusters in a spherical shell of 25/hMpc in thickness centered on the void no significant diverging motion (expected to be generated by the mass deficit in the void) has been detected. This implies that cosmological models with low {Omega}_m_ are preferred. To explain small mass underdensity inside the Giant Void, a mechanism of void formation with strong biasing is required.
