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LSST is expected to yield ~10^7 light curves over the course of its mission, which will require a concerted effort in automated classification. Stochastic processes provide one means of quantitatively describing variability with the…

Instrumentation and Methods for Astrophysics · Physics 2017-04-26 J. C. Zinn , C. S. Kochanek , S. Kozłowski , A. Udalski , M. K. Szymański , I. Soszyński , Ł. Wyrzykowski , K. Ulaczyk , R. Poleski , P. Pietrukowicz , J. Skowron , P. Mróz , M. Pawlak

We identify the RR Lyrae and delta Scuti (DSCT) stars in three catalogs of GALEX variable sources. The NUV amplitude of RR Lyrae stars is about twice that in V-band, so we find a larger percentage of low amplitude variables than catalogs…

Solar and Stellar Astrophysics · Physics 2015-06-22 T. D. Kinman , Warren R. Brown

The All Sky Automated Survey (ASAS) monitors bright stars (8 mag < V < 14 mag) south of declination +28 deg. The ASAS Catalogue of Variable Stars (ACVS) presently contains 50,099 objects; among them are 2212 objects classified as RR Lyrae…

Astrophysics · Physics 2008-11-26 D. M. Szczygiel , D. C. Fabrycky

In this work, we propose a novel method to classify close binary stars, derived from the dynamical structure inherent in their light curves. We apply the technique to light curves of binaries from the revised Kepler Eclipsing binary…

Solar and Stellar Astrophysics · Physics 2025-06-05 Anisha R. V. Kashyap , D. Pawar , R. Misra , G. Ambika , Sandip V George

Microvariability consists in small time scale variations of low amplitude in the photometric light curves of quasars, and represents an important tool to investigate their inner core. Detection of quasar microvariations is challenging for…

Instrumentation and Methods for Astrophysics · Physics 2016-08-08 J. A. de Diego , J. Polednikova , A. Bongiovanni , A. M. Pérez García , M. A. De Leo , T. Verdugo , J. Cepa

[ABRIDGED] $\omega$ Centauri (NGC 5139) contains large numbers of variable stars of different types and, in particular, more than a hundred RR Lyrae stars. We have conducted a variability survey of $\omega$ Cen in the NIR, using ESO's 4.1m…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. Navarrete , R. Contreras Ramos , M. Catelan , C. M. Clement , F. Gran , J. Alonso-García , R. Angeloni , M. Hempel , I. Dékány , D. Minniti

We performed R-band time series observations of the young, metal rich open cluster NGC 2301 for 12 nights in Feb. 2004. B images were also obtained and color magnitude diagrams, having limits of R=19.5 and B=21.5, were produced. Only asmall…

This work is part of an effort to detect secular variable objects in large scale surveys by analysing their path in color-magnitude diagrams. To this aim, we first present the variability morphologies in the V/V-I diagram of several types…

Solar and Stellar Astrophysics · Physics 2015-05-13 Maxime Spano , Nami Mowlavi , Laurent Eyer , Gilbert Burki

Combined studies of variable stars and stellar clusters open great horizons, and they allow us to improve our understanding of stellar cluster formation and stellar evolution. In that prospect, the Gaia mission will provide astrometric,…

We present the results of a systematic search for multiperiodic pulsators among the Galactic Bulge RR Lyrae stars of the OGLE-1 sample. We identify one "canonical" double-mode variable (RRd star) pulsating in two radial modes. In 38 stars…

Astrophysics · Physics 2009-11-07 P. Moskalik , E. Poretti

R Coronae Borealis variable stars are suspected to sporadically eject optically thick dust clouds causing, when one of them lies on the line-of-sight, a huge brightness decline in visible light. Mid-infrared interferometric observations of…

Astrophysics · Physics 2009-11-13 I. C. Leao , Patrick De Laverny , O. Chesneau , D. Mekarnia , J. R. De Medeiros

The number of stars observed by the Optical Gravitational Lensing Experiment (OGLE) project in the Galactic bulge offers an invaluable chance to study RR Lyrae stars in a statistical manner. We used data of 3141 fundamental-mode RR Lyrae…

Solar and Stellar Astrophysics · Physics 2020-03-10 M. Skarka , Z. Prudil , J. Jurcsik

Pulsating stars are universally recognized as precise distance indicators and tracers of stellar populations. Their variability, combined with well-defined relationships between pulsation properties and intrinsic evolutionary parameters…

Solar and Stellar Astrophysics · Physics 2024-11-05 Giulia De Somma , Marcella Marconi , Santi Cassisi , Roberto Molinaro

New accurate and homogeneous optical UBVRI photometry has been obtained for variable stars in the Galactic globular $\omega$ Cen (NGC 5139). We secured 8202 CCD images covering a time interval of 24 years and a sky area of 84x48 arcmin. The…

We present new optical (BVI) time-series data for the evolved variable stars in the Carina dwarf spheroidal galaxy. The quality of the data and the observing strategy allowed us to identify 14 new variable stars. Eight out of the 14 are RR…

RR Lyrae stars (RRLs) are old pulsating variables widely used as metallicity tracers due to the correlation between their metal abundances and light curve morphology. With ESA Gaia DR3 providing light curves for about 270,000 RRLs, there is…

Solar and Stellar Astrophysics · Physics 2025-05-28 Lorenzo Monti , Tatiana Muraveva , Alessia Garofalo , Gisella Clementini , Maria Letizia Valentini

The catalogue of the Johnson-Cousins B,V and I light curves obtained for 162 variable stars (135 RR Lyrae, 4 candidate Anomalous Cepheids, 11 Classical Cepheids, 11 eclipsing binaries and 1 delta Scuti star) in two areas close to the bar of…

We present results of a photometric survey for variable stars in the field of the globular cluster Omega Centauri. The observed region was centered roughly on the cluster core and covered 644 arcmin^2. The cluster was monitored on 59 nights…

Astrophysics · Physics 2009-11-10 J. Kaluzny , A. Olech , I. B. Thompson , W. Pych , W. Krzeminski , A. Schwarzenberg-Czerny

The MACHO Project collected photometry of many RR Lyrae stars from its observations of the Milky Way's bulge. We examined the lightcurves of 3256 stars identified as RRab Lyr variables by \cite{Kund2008}, subtracting an empirical model of…

Solar and Stellar Astrophysics · Physics 2015-03-19 Michael W. Richmond

We present 87 candidates for RR Lyrae variable stars in binary systems, based on our new search using the light-travel time effect (LTTE) and observed - calculated ($O-C$) diagrams in the Galactic bulge time-series photometry of the Optical…