- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1220
- Title:
- Vi light curves of NGC6333 variables
- Short Name:
- J/MNRAS/434/1220
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report CCD V and I time series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05mag for stars brighter than V~19.0mag, even in the crowded central regions of the cluster. The high photometric precision has resulted in the discovery of two new RRc stars, three eclipsing binaries, seven long-term variables and one field RRab star behind the cluster. A detailed identification chart and equatorial coordinates are given for all the variable stars in the field of our images of the cluster. Our data together with the literature V-data obtained in 1994 and 1995 allowed us to refine considerably the periods for all RR Lyrae stars. The nature of the new variables is discussed. We argue that variable V12 is a cluster member and an Anomalous Cepheid. Secular period variations, double-mode pulsations and/or the Blazhko-like modulations in some RRc variables are addressed. Through the light-curve Fourier decomposition of 12 RR Lyrae stars we have calculated a mean metallicity of [Fe/H]_ZW_=-1.70+/-0.01(statistical)+/-0.14(systematic) or [Fe/H]_UVES_=-1.67+/-0.01(statistical)+/-0.19(systematic). Absolute magnitudes, radii and masses are also estimated for the RR Lyrae stars. A detailed search for SX Phe stars in the Blue Straggler region was conducted but none were discovered. If SX Phe exist in the cluster then their amplitudes must be smaller than the detection limit of our photometry. The colour-magnitude diagram has been corrected for heavy differential reddening using the detailed extinction map of the cluster of Alonso-Garcia et al. (2012, Cat. J/AJ/143/70). This has allowed us to set the mean cluster distance from two independent estimates; from the RRab and RRc absolute magnitudes, we find 8.04+/-0.19 and 7.88+/-0.30kpc, respectively.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AcA/66/131
- Title:
- VI light curves of SMC and LMC RR Lyrae
- Short Name:
- J/AcA/66/131
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the largest collection of RR Lyrae stars in the Magellanic System and in its foreground. The sample consists of 45451 RR Lyr stars, of which 39082 were detected toward the Large Magellanic Cloud and 6369 toward the Small Magellanic Cloud. We provide long-term time-series photometric measurements collected during the fourth phase of the Optical Gravitational Lensing Experiment (OGLE-IV). We discuss several potential astrophysical applications of our collection: investigation of the structure of the Magellanic Clouds and the Galactic halo, studies of the globular clusters in the Magellanic System, analysis of double-mode RR Lyr stars, and search for RR Lyr stars in eclipsing binary systems.
- ID:
- ivo://CDS.VizieR/J/AcA/60/17
- Title:
- VI light curves of SMC classical Cepheids
- Short Name:
- J/AcA/60/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The seventh part of the OGLE-III Catalog of Variable Stars (OIII-CVS) consists of 4630 classical Cepheids in the Small Magellanic Cloud (SMC). The sample includes 2626 fundamental-mode (F), 1644 first-overtone (1O), 83 second-overtone (2O), 59 double-mode F/1O, 215 double-mode 1O/2O, and three triple-mode classical Cepheids. For each object basic parameters, multi-epoch VI photometry collected within 8 or 13 years of observations, and finding charts are provided in the OGLE Internet archive.
- ID:
- ivo://CDS.VizieR/J/AcA/61/217
- Title:
- VI light curves of SMC long-period variables
- Short Name:
- J/AcA/61/217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The thirteenth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains 19 384 long-period variables (LPVs) detected in the Small Magellanic Cloud. The sample is composed of 352 Mira stars, 2222 semiregular variables (SRVs) and 16 810 OGLE Small Amplitude Red Giants (OSARGs). Sources are divided into oxygen-rich and carbon-rich stars. The catalog includes time-series VI photometry obtained between 1997 and 2009.
- ID:
- ivo://CDS.VizieR/J/AcA/60/165
- Title:
- VI light curves of SMC RR Lyrae
- Short Name:
- J/AcA/60/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ninth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) comprises RR Lyr stars in the Small Magellanic Cloud (SMC). Our sample consists of 2475 variable stars, of which 1933 pulsate in the fundamental mode (RRab), 175 are the first overtone pulsators (RRc), 258 oscillate simultaneously in both modes (RRd) and 109 stars are suspected second-overtone pulsators (RRe). 30 objects are Galactic RR Lyr stars seen in the foreground of the SMC.
- ID:
- ivo://CDS.VizieR/J/AcA/60/91
- Title:
- VI light curves of SMC type II Cepheids
- Short Name:
- J/AcA/60/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The eighth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains type II Cepheids in the Small Magellanic Cloud (SMC). The sample consists of 43 objects, including 17 BL Her, 17 W Vir and 9 RV Tau stars (first examples ever found in the SMC). Seven stars have been classified as peculiar W Vir stars - a recently identified subclass of type II Cepheids. These stars have distinctive light curves, are brighter and bluer than the ordinary W Vir variables. We confirm that a large fraction of the peculiar W Vir stars are members of binary systems.
- ID:
- ivo://CDS.VizieR/J/A+A/369/862
- Title:
- VI light curves of the variable stars in M92
- Short Name:
- J/A+A/369/862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of a search for variable stars in the central region of the Oosterhoff II type globular cluster M 92 are presented. Out of the 28 variable and suspected variable stars listed in the Catalogue of Variable Stars in Globular Clusters (Clement, 1997, Cat. <V/97>) only two were not observed. Surprisingly, almost half of the observed suspected variables did not show any evidence of variability. Only one out of the 11 candidate RR Lyrae variables of Kadla et al. (1983PZ.....21..827K) appeared to be variable. Moreover, variable V7, until now classified as an RR Lyrae star with a period of about 0.515d, turned out to be of the BL Herculis type, with the period approximately twice that long. In addition, six new variables were found in the very core of the cluster: four of the RR Lyrae and the remaining two of the SX Phoenicis type. RRc variable V11 shows changes in the light curve shape. Due to the aliasing problems, however, we can state only that this star is biperiodic. There is a possibility that V11 belongs to the new group of recently discovered double-period RRc variables pulsating in non-radial mode. Altogether, light curves were obtained for 20 variable stars. The total number of known RR Lyrae stars in M92 equals now 17, 11 of type RRab and the remaining 6, RRc. The CCD observations presented here were carried out at the Bialkow station of the Wroclaw University Observatory with the same equipment as that described by Kopacki & Pigulski (1995AcA....45..753K). Two 6x4arcmin^2^ fields of view, one centred approximately on the core of M92 and the other shifted about 2.5arcmin north and 2.6arcmin east, were observed through V and I_c_ filters of the Johnson-Kron-Cousins UBV(RI)_c_ system. The observations were carried out in two seasons: on 9 nights between 1998 July 20 and September 1, and on 17 nights between 2000 May 4 and June 20. During the 1998 season only a few frames of the second field were taken. The main field, centred on the core of the cluster, was observed during both seasons.
- ID:
- ivo://CDS.VizieR/J/A+A/398/541
- Title:
- VI light-curves of the variable stars in M13
- Short Name:
- J/A+A/398/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- VI light-curves of variable stars in the globular cluster M13 are presented. They are based on the CCD observations carried out at the Bialkow station of the Wroclaw University Observatory using 60-cm reflecting telescope and the CCD camera. A 6x4 arcmin-squared field of view covering the core of the cluster was observed through V and I_C filters of the Johnson-Kron-Cousins UBV(RI)_C system. About 300 frames in both filters were taken during 23 nights between 2001 February 27 and August 1. The CCD images were analyzed with the DAOPHOT profile-fitting software and Image Subtraction Method. The main result of this study is discovery of five RR Lyrae and one SX Poenicis stars. Moreover we detect non-radial pulsations in RRc star v36. We also comment the variability of all observed suspected variable stars in M13.
- ID:
- ivo://CDS.VizieR/J/AcA/63/429
- Title:
- VI light curves of 10 variables in NGC288
- Short Name:
- J/AcA/63/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for variable stars in the globular cluster NGC 288 was carried out using a time-series of CCD images in the V and I filters. The photometry of all stellar sources in the field of view of our images, down to V~19mag, was performed using difference image analysis (DIA). For stars of~15mag, measurement accuracies of ~8mmag and ~10mmag were achieved for V and I respectively. Three independent search strategies were applied to the 5525 light curves but no new variables were found above the threshold limits characteristic of our data set. The use of older data from the literature combined with the present data allowed the refinement of the periods of all known variables. Fourier light curve decomposition was performed for the RRab and the RRc stars to obtain an estimate of [Fe/H]_ZW_=-1.62+/-0.02 (statistical) +/-0.14 (systematic). A true distance modulus of 14.768+/-0.003mag (statistical) +/-0.042mag (systematic), or a distance of 8.99+/-0.01kpc (statistical) +/-0.17kpc (systematic) was calculated from the RRab star. The RRc star predicts a discrepant distance about one kiloparsec shorter but it is possibly a Blazhko variable. An independent distance from the P-L relationship for SX Phe stars leads to a distance of 8.9+/-0.3kpc. The SX Phe stars V5 and V9 are found to be double mode pulsators.
- ID:
- ivo://CDS.VizieR/J/AJ/123/279
- Title:
- VI Photometry and Variables in NGC 3201
- Short Name:
- J/AJ/123/279
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Globular Cluster NGC 3201 was monitored for the existence of variable stars with 16.5<V<20 and 0.2days<period<5days. The files v*.dat contain time-series photometry data in V and I for the 14 variables detected in the field of NGC 3201. Only V6 (a blue straggler contact binary) is a member of the cluster. Due to its low-latitude position, interstellar extinction is present across the field of the cluster. The file phot.dat contains VI photometry data on the monitored stars. These data are NOT corrected for extinction. The variables V7, V8, and V9 were discovered during a follow-up observing run with a different telescope and therefore do not lie in the field covered by phot.dat. Variables V1-V9 are contact system eclipsing binaries, V10 is an RR Lyrae, V11 a semi-detached Algol type binary, V12 a detached binary system, and V13 and V14 are unclassified variable systems.
