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16601. Variables in metal-rich clusters. IV. NGC 6496
ID:
ivo://CDS.VizieR/J/AJ/149/40
Title:
Variables in metal-rich clusters. IV. NGC 6496
Short Name:
J/AJ/149/40
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present VI-band photometry for stars in the metal-rich globular cluster NGC 6496. Our time-series data were cadenced to search for long-period variables (LPVs) over a span of nearly two years, and our variability search yielded the discovery of 13 new variable stars, of which 6 are LPVs, 2 are suspected LPVs, and 5 are short-period eclipsing binaries. An additional star was found in the ASAS database, and we clarify its type and period. We argue that all of the eclipsing binaries are field stars, while five to six of the LPVs are members of NGC 6496. We compare the period-luminosity distribution of these LPVs with those of LPVs in the Large Magellanic Cloud and 47 Tucanae, and with theoretical pulsation models. We also present a VI color-magnitude diagram, display the evolutionary states of the variables, and match isochrones to determine a reddening of E(B-V)=0.21+/-0.02mag and apparent distance modulus of 15.60+/-0.15mag.
16602. Variables in Omega Cen Fields 5139A-C
ID:
ivo://CDS.VizieR/J/A+AS/120/139
Title:
Variables in Omega Cen Fields 5139A-C
Short Name:
J/A+AS/120/139
Date:
21 Oct 2021
Publisher:
CDS
Description:
Tables 11-50 contain V band light curves for 40 variables reported in the paper. Tables 51-53 and 54-56 contain VI photometry presented in Figs. 12 and 13, respectively.
16603. Variables in Omega Cen Fields 5139D-F
ID:
ivo://CDS.VizieR/J/A+AS/122/471
Title:
Variables in Omega Cen Fields 5139D-F
Short Name:
J/A+AS/122/471
Date:
21 Oct 2021
Publisher:
CDS
Description:
Tables 1-30 contain V band light curves for 30 variables reported in the paper. Tables 31-33 and 34-36 contain VI photometry presented in Figs. 8 and 9, respectively.
16604. Variables in Praesepe identified with KELT
ID:
ivo://CDS.VizieR/J/AJ/135/907
Title:
Variables in Praesepe identified with KELT
Short Name:
J/AJ/135/907
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Kilodegree Extremely Little Telescope (KELT) project is a small aperture, wide-angle search for planetary transits of solar-type stars. In this paper, we present the results of a commissioning campaign with the KELT telescope to observe the open cluster Praesepe for 34 nights in early 2005. Light curves were obtained for 69337 stars, out of which we identify 58 long-period variables and 152 periodic variables. Sixteen of these are previously known as variable, yielding 194 newly discovered variable stars for which we provide properties and light curves. We also searched for planetary-like transits, finding four transit candidates. Follow-up observations indicate that two of the candidates are astrophysical false positives, with two candidates remaining as potential planetary transits.
16605. Variables in Sextans dSph galaxy
ID:
ivo://CDS.VizieR/J/AJ/110/2166
Title:
Variables in Sextans dSph galaxy
Short Name:
J/AJ/110/2166
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe a survey for variable stars in the Sextans dwarf spheroidal (dSph) galaxy based on the analysis of 113 B and 48 V CCD images of four fields covering a total area of 18'x18'. We have identified 44 variables: 36 RR Lyr star, 6 anomalous Cepheids, one long-period red variable, all probable members of Sextans, and one foreground contact binary. We have used the pulsating stars to derive a true distance modulus of 19.67+/-0.15 for Sextans (or D=86+/-6kpc), where the error is primarily due to uncertainties in the luminosity-metallicity relation for RR Lyr stars. Based on our new data we conclude that [Fe/H]_Sex=-1.6+/-0.2, somewhat higher than the value from Suntzeff et al. (1993ApJ...418..208S) obtained from the analysis of fiber spectroscopy of the near-IR Calcium triplet. We present a new deep color-magnitude diagram for Sextans which reveals the presence of anomalous Cepheids in the galaxy. This young population may represent as much as 25% of the total stellar content of Sextans. We find a surprisingly strong correlation between the frequency of anomalous Cepheids in dSph galaxies and galaxian luminosity and speculate on the possible origin of this strange effect. The RR Lyr stars in Sextans do not exhibit the Oosterhoff dichotomy observed in globular clusters and in the Galactic halo field.
16606. Variables in the fields of M35 and NGC2158
ID:
ivo://CDS.VizieR/J/MNRAS/447/3536
Title:
Variables in the fields of M35 and NGC2158
Short Name:
J/MNRAS/447/3536
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a multiyear survey aimed at collecting (1) high-precision (~5 milli-mag), (2) fast-cadence (~3-min), and (3) relatively long duration (~10d) multiband photometric series. The goal of the survey is to discover and characterize efficiently variable objects and exoplanetary transits in four fields containing five nearby open clusters spanning a broad range of ages. More in detail, our project will (1) constitute a preparatory survey for the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) mounted at the Telescopio Nazionale Galileo (TNG), which will be used for spectroscopic follow-up of any target of interest that this survey discovers or characterizes, (2) measure rotational periods and estimate the activity level of targets we are already monitoring with HARPS and HARPS-N for exoplanet transit search, and (3) long-term characterization of selected targets of interest in open clusters within the planned K2 fields. In this first paper, we give an overview of the project, and report on the variability of objects within the first of our selected fields, which contains two open clusters: M35 and NGC 2158. We detect 519 variable objects, 273 of which are new discoveries, while the periods of most of the previously known variables are considerably improved.
16607. Variables in 47 Tuc
ID:
ivo://CDS.VizieR/J/ApJ/559/1060
Title:
Variables in 47 Tuc
Short Name:
J/ApJ/559/1060
Date:
21 Oct 2021
Publisher:
CDS
Description:
Differential time series photometry has been derived for 46,422 main-sequence stars in the core of 47 Tucanae. The observations consisted of near-continuous 160 s exposures alternating between the F555W and F814W filters for 8.3 days in 1999 July with the Wide Field Planetary Camera 2 on the Hubble Space Telescope. Using Fourier and other search methods, 11 detached eclipsing binaries and 15 W Ursa Majoris stars have been discovered plus an additional 10 contact or near-contact noneclipsing systems. After correction for nonuniform area coverage of the survey, the observed frequencies of detached eclipsing binaries and W UMa stars within 90" of the cluster center are 0.022% and 0.031%, respectively. The data were taken over an 8.3 day period, 1999 July 3-11, during which HST was pointed continuously at 47 Tuc.
16608. Variables near NGC 7635
ID:
ivo://CDS.VizieR/J/other/IBVS/4441
Title:
Variables near NGC 7635
Short Name:
J/other/IBVS/444
Date:
21 Oct 2021
Publisher:
CDS
Description:
A group of new and known variable stars in the field of the emission nebula NGC 7635 was studied by Rosino, Bianchini, and Martino (1976A&AS...24....1R)). In the source paper, approximate positions, spectral types, and elements of variation were presented along with finder charts for the thirty-two new variables. All but one of these are now named variables. Although the positions provided are generally accurate, they are not precise. For the fainter stars especially, precise positions are required both for their recovery for further study at the telescope and for linkage within other surveys such as IRAS.
16609. Variables observed in the Galactic disk by AST3-1
ID:
ivo://CDS.VizieR/J/AJ/153/104
Title:
Variables observed in the Galactic disk by AST3-1
Short Name:
J/AJ/153/104
Date:
21 Oct 2021
Publisher:
CDS
Description:
AST3-1 is the second-generation wide-field optical photometric telescope dedicated to time-domain astronomy at Dome A, Antarctica. Here, we present the results of an i-band images survey from AST3-1 toward one Galactic disk field. Based on time-series photometry of 92583 stars, 560 variable stars were detected with i magnitude {<=}16.5mag during eight days of observations; 339 of these are previously unknown variables. We tentatively classify the 560 variables as 285 eclipsing binaries (EW, EB, and EA), 27 pulsating variable stars ({delta} Scuti, {gamma} Doradus, {delta} Cephei variable, and RR Lyrae stars), and 248 other types of variables (unclassified periodic, multiperiodic, and aperiodic variable stars). Of the eclipsing binaries, 34 show O'Connell effects. One of the aperiodic variables shows a plateau light curve and another variable shows a secondary maximum after peak brightness. We also detected a complex binary system with an RS CVn-like light-curve morphology; this object is being followed-up spectroscopically using the Gemini South telescope.
16610. Variable sources detected by INTEGRAL
ID:
ivo://CDS.VizieR/J/A+A/522/A68
Title:
Variable sources detected by INTEGRAL
Short Name:
J/A+A/522/A68
Date:
21 Oct 2021
Publisher:
CDS
Description:
In 6 years of operation, INTEGRAL/ISGRI revealed more than 500 sources. Many of these sources are variable. Taking into account that nearly half of INTEGRAL/ISGRI sources are new and many of them are still unidentified, the variability properties of the sources can serve as additional parameters that may help to classify and identify the unknown sources. In order to study the variability properties of the sources detected by INTEGRAL/ISGRI we develop a method to quantify the variability of a source. We describe here our techniques and compile a catalog of the sources that fit our criteria of variability.

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