- ID:
- ivo://CDS.VizieR/J/AJ/139/2300
- Title:
- BVIc light curves of 3 type II Cepheids
- Short Name:
- J/AJ/139/2300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves in the B, V, and Ic passbands have been obtained for the type II Cepheids V154 in M3 and V42 and V84 in M5. Alternating cycle behavior, similar to that seen among RV Tauri variables, is confirmed for V84. Old and new observations, spanning more than a century, show that V154 has increased in period while V42 has decreased in period. V84, on the other hand, has shown large, erratic changes in period that do not appear to reflect the long-term evolution of V84 through the Hertzsprung-Russel diagram.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/372/1657
- Title:
- BVI(c) light curves of variables in M3
- Short Name:
- J/MNRAS/372/1657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present time-series data on the variable stars of the galactic globular cluster Messier 3 (M3). We give BVI_C_ light curves for 226 RR Lyrae, 2 SX Phe and 1 W Vir type variables, along with estimated fundamental photometric parameters such as intensity and magnitude-averaged brightness and pulsation periods. In some cases, the periods we have found significantly differ from the previously published ones. This is the first published light curve and period determination for variable V266. The I-band light curve has not been observed previously for numerous (76) variables. Three new RR Lyrae variables have been discovered. Groups of RR Lyrae variables that belong to different evolutionary stages and have been separated previously on the basis of V data were found here for all colours and colour indices by cluster analysis. The I-band period-luminosity relation is also discussed. From the 66 modulated (Blazhko type) RR Lyrae stars we investigated, six are newly identified and two of them are first overtone pulsators. In the case of 13 RR Lyrae, the period of Blazhko cycle has been estimated for the first time. V252 is identified as a new RRd variable. Amplitude ratios of RRd stars have been investigated to search possible mode content changes. In contrast to previous publications no changes have been found. Problems with the sampling of the time-series of typical cluster variability surveys are demonstrated.
- ID:
- ivo://CDS.VizieR/J/ApJS/137/209
- Title:
- BVIc photoelectric obs. of southern Cepheids
- Short Name:
- J/ApJS/137/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 2097 photometric observations in the BVI_C_ system are presented for 117 Cepheids located in the southern hemisphere. The main purpose of the photometry is to provide new epochs of maximum brightness for studying Cepheid period changes, as well as to establish current light elements for the Cepheids.
- ID:
- ivo://CDS.VizieR/J/other/NewA/11.262
- Title:
- BVIc photometry in Lynga 11
- Short Name:
- J/other/NewA/11.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained CCD BVI_KC_ photometry down to V~21.5 for the open cluster Lynga 11 and its surrounding field. This previously unstudied object appears to be rich and highly absorbed. A cluster angular radius of 4.5+/-0.5, equivalent to (3.0+/-0.3)pc, is estimated from star counts in 100-pixel a side boxes distributed throughout the whole observed field. Our analysis suggests that Lynga 11 is moderately young and probably of solar metallicity.
- ID:
- ivo://CDS.VizieR/J/AN/322/73
- Title:
- BVIc photometry in NGC 2976
- Short Name:
- J/AN/322/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVIc photometry of the brightest stars and compact star clusters in NGC 2976, a dwarf galaxy in the interacting M81/M82 group. Deep CCD images of the galaxy were obtained with the 6m-Telescope of the Special Astrophysical Observatory (Russia) at arcsec resolution. About 290 young stars and concentrated young clusters were measured. Supplementaxy data in the ultraviolet are taken from the literature. The extinction to the measured objects is comparatively low, E(B-V)~0.15-0.20mag. We estimate the ages of youngest resolved stars and concentrated star clusters to be ~5x10^6^years. This population is concentrated in a broad stripe facing M81. In the central disk the population is a bit older, about 8x10^6^years, this may be a hint to an outward spreading star formation process. The metallicity of the disk population is estimated as solar (z~0.02) from a fitting to Padova theoretical stellar isochrones.
- ID:
- ivo://CDS.VizieR/J/AZh/88/886
- Title:
- BVIc photometry of Cepheids from ASAS-3 catalog
- Short Name:
- J/AZh/88/886
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In 2008-2010, we obtained 6095 CCD frames in the BVIc photometric system for 49 classical Cepheids discovered in the ASAS-3 project. The observations were obtained on the 76-cm telescope of the South African Astronomical Observatory (SAAO, RSA) and the 40-cm telescope of the Cerro Armazones Observatory of the Catholic University of the North (OCA, Chile), with a SBIGCCD ST-10XME camera. We present tabulated observations, light curves, and revised elements for the brightness variations.
- ID:
- ivo://CDS.VizieR/J/AJ/140/677
- Title:
- BVIc photometry of IC 4665
- Short Name:
- J/AJ/140/677
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, BVIc photometric survey of the young open cluster IC 4665, which improves on previous studies of this young cluster by incorporating a rigorous standardization procedure, thus providing high-fidelity colors and magnitudes for cluster members. We use this new photometric dataset to reevaluate the properties (age and distance) of IC 4665.
- ID:
- ivo://CDS.VizieR/J/PASJ/56/295
- Title:
- BVIc photometry of old open clusters
- Short Name:
- J/PASJ/56/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric data for 14 galactic open clusters taken by the 65cm telescope at Gunma Astronomical Observatory. They were in the anti-galactic center region selected from the Catalog of Open Cluster Data (Lynga, 1987, See Cat. <J/A+A/438/1163>). We estimated the parameters of the clusters, i.e., age, metallicity, distance, and reddening, by fitting Padova isochrones to the color-magnitude diagram.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1482
- Title:
- BVIc photometry of Trumpler 20
- Short Name:
- J/MNRAS/391/1482
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We show that the open cluster Trumpler 20, contrary to the earlier findings, is actually an old Galactic open cluster. New CCD photometry and high-resolution spectroscopy are used to derive the main parameters of this cluster. At [Fe/H]=-0.11 for a single red giant star, the metallicity is slightly subsolar. The best fit to the colour-magnitude diagrams is achieved using a 1.3-Gyr isochrone with convective overshoot. The cluster appears to have a significant reddening at E(B-V)=0.46 (for B0 spectral type), although for red giants this high reddening yields the colour temperature exceeding the spectroscopic Teff by about 200K. Trumpler 20 is a very rich open cluster, containing at least 700 members brighter than M_V_=+4. It may extend over the field of view available in our study at 20x20arcmin^2^.
- ID:
- ivo://CDS.VizieR/J/A+AS/133/181
- Title:
- BVI imaging of 20 irregular galaxies
- Short Name:
- J/A+AS/133/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present B, V and I CCD stellar photometry for a sample of 20 field irregular dwarf galaxies. Their corrected radial velocity is V_0_<500km/s. Most of them have been resolved into stars for the first time. Based on photometry of their brightest blue stars we have derived the following distances: 5.9Mpc (UGC 685), 5.4Mpc (UGC 1281), 7.2Mpc (UGC 3303), 7.0Mpc (UGC 3476), 7.3:Mpc (UGC 3600), 7.2:Mpc (UGC 3698), 7.9Mpc (NGC 2337), 8.6Mpc (UGC 3817), 5.7Mpc (UGC 3860), 5.6Mpc (UGC 4426), >=7.9Mpc (F 565-v1), 7.4:Mpc (UGC 5086), 7.1Mpc (UGC 5272), 5.9Mpc (UGC 5340), 7.1Mpc (UGC 5427), 2.7:Mpc (UGC 5456), 6.6Mpc (NGC 3274), 9.3Mpc (UGC 5889), 5.2Mpc (NGC 5238), and 8.0Mpc (UGC 9405). Our sample exhibits diverse morphological properties evidently caused by their different starburst activity. The galaxy sample has a median integral absolute magnitude M_B_=-14.6 and a median integral colour (B-V)_T_=+0.47. One dwarf, UGC 5340, stands out by its very blue colour, (B-V)_T_=+0.18, and by its high M(HI)/L ratio, as expected for young galaxies. Four objects of the sample are IRAS sources. Being well isolated systems, the considered galaxies may be used to estimate a local value of the Hubble parameter, H=V_0_/D. For half of the sample galaxies their individual H- values are concentrated within [58-68]km/s/Mpc with a median of 65km/s/Mpc.
