- ID:
- ivo://CDS.VizieR/J/AJ/148/126
- Title:
- Light curves of four overcontact binaries
- Short Name:
- J/AJ/148/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze new, high quality multicolor light curves of four overcontact binaries: AK Her, HI Dra, V1128 Tau, and V2612 Oph, and determine their orbital and physical parameters using the modeling program of G. Djurasevic and recently published results of radial velocity studies. The achieved precision in absolute masses is between 10% and 20%, and the precision in absolute radii is between 5% and 10%. All four systems are W UMa-type binaries with bright or dark spots indicative of mass and energy transfer or surface activity. We estimate the distances and the ages of the systems using the luminosities computed through our analysis, and perform an O-C study for V1128 Tau, which reveals a complex period variation that can be interpreted in terms of mass loss/exchange and either the presence of the third body, or the magnetic activity on one of the components. We conclude that further observations of these systems are needed to deepen our understanding of their nature and variability.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/145/60
- Title:
- Light curves of GN Boo, BL Leo, and V1918 Cyg
- Short Name:
- J/AJ/145/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometry for three short-period contact binaries, GN Boo, BL Leo, and V1918 Cyg, observed from 2008 December to 2012 April using several small telescopes in China. Photometric models were deduced from new observations using the updated Wilson-Devinney Code. The results show that GN Boo and BL Leo are W-type contact binaries, while V1918 Cyg is an A-type one. The mass ratios and fill-out factors are q=0.320(+/-0.002) and f=5.8(+/-0.1)% for GN Boo, q=0.476(+/-0.005) and f=21.3(+/-1.1)% for BL Leo, q=0.264(+/-0.002), and f=49.7(+/-0.7)% for V1918 Cyg, respectively. From the (O-C) curves, it is discovered that the orbital periods of three binaries have varied in a complicated way, i.e., cyclic oscillation for GN Boo, long-term period decrease for BL Leo, and both for V1918 Cyg. The cyclic variations for GN Boo and V1918 Cyg may probably be attributed to the magnetic activity of the primary component or light-time effect due to the third body. Meanwhile, the secular period decreases for BL Leo and V1918 Cyg may result from mass transfer from the primary to the secondary, accompanying the mass and angular momentum loss from the central system. Finally, GN Boo, BL Leo, and V1918 Cyg will evolve into deep contact binaries. Additionally, a statistical study of 37 contact binaries with decreasing periods is given. We obtained the relations of q-f and q-dlnP/dt, and preliminarily determined the mass loss rate of dln M/dt from the binary system.
- ID:
- ivo://CDS.VizieR/J/AJ/145/80
- Title:
- Light curves of HS Aqr, EG Cep, VW LMi, DU Boo
- Short Name:
- J/AJ/145/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze new multicolor light curves for four close late-type binaries: HS Aqr, EG Cep, VW LMi, and DU Boo, in order to determine the orbital and physical parameters of the systems and estimate the distances. The analysis is done using the modeling code of G. Djurasevic, and is based on up-to-date measurements of spectroscopic elements. All four systems have complex, asymmetric light curves that we model by including bright or dark spots on one or both components. Our findings indicate that HS Aqr and EG Cep are in semi-detached, while VW LMi and DU Boo are in overcontact configurations.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1447
- Title:
- Light curves of variable stars in {omega} Cen
- Short Name:
- J/AJ/133/1447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a variable star catalog of an extensive ground-based wide-field variability survey in the globular cluster omega Centauri. Using the Australian National University 40 inch (1m) telescope at Siding Spring Observatory, the cluster was observed with a 52'x52' (0.75deg^2^) field for 25 nights, from 2003 May 2 to May 27. A total of 187 variable stars were identified in the field, 81 of which are new discoveries. This work comprises the widest field variability survey yet undertaken for this cluster. Here we present the V+R light curves and preliminary analysis of the detected variable stars, comprising 58 eclipsing binaries, 69 RR Lyrae stars, 36 long-period variables (P>=2days), and 24 miscellaneous pulsators including 15 SX Phoenicis stars and two type II Cepheids.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A33
- Title:
- LMC 162 eccentric eclipsing binaries light curve
- Short Name:
- J/A+A/640/A33
- Date:
- 17 Dec 2021 07:53:18
- Publisher:
- CDS
- Description:
- We present an extensive study of 162 early-type binary systems located in the LMC galaxy that show apsidal motion and have never been studied before. For the ample systems, we performed light curve and apsidal motion modelling for the first time. These systems have a median orbital period of 2.2 days and typical periods of the apsidal motion were derived to be of the order of decades. We identified two record-breaking systems. The first, OGLE LMC-ECL-22613, shows the shortest known apsidal motion period among systems with main sequence components (6.6 years); it contains a third component with an orbital period of 23 years. The second, OGLE LMC-ECL-17226, is an eccentric system with the shortest known orbital period (0.9879 days) and with quite fast apsidal motion period (11 years). Among the studied systems, 36 new triple-star candidates were identified based on the additional period variations. This represents more than 20% of all studied systems, which is in agreement with the statistics of multiples in our Galaxy. However, the fraction should only be considered as a lower limit of these early-type stars in the LMC because of our method of detection, data coverage, and limited precision of individual times of eclipses.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/249
- Title:
- LMC eclipsing binaries in the MACHO database
- Short Name:
- J/ApJ/663/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eclipsing binaries offer a unique opportunity to determine fundamental physical parameters of stars by using the constraints on the geometry of the systems. Here we present a reanalysis of publicly available two-color observations of about 6800 stars in the Large Magellanic Cloud obtained by the MACHO Project between 1992 and 2000 and classified as eclipsing variables. Of these, fewer than half are genuine eclipsing binaries. We determined new periods and classified the stars, 3031 in total, using the Fourier parameters of the phased light curves.
- ID:
- ivo://CDS.VizieR/J/AJ/123/3460
- Title:
- Low-amplitude variables in NGC 6791
- Short Name:
- J/AJ/123/3460
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have undertaken a long-term project, the Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. As our first target, we have chosen NGC 6791, a very old, populous, metal-rich cluster. We present the results of a test observing run at the F.L. Whipple Observatory's 1.2 m telescope, from 2001 July 6 to August 1. Our primary goal is to demonstrate the feasibility of obtaining the accuracy required for planetary-transit detection using image subtraction photometry on data collected with a 1 m class telescope. We present a catalog of 62 variable stars, 47 of them newly discovered, most with low-amplitude variability. Among those there are several BY Draconis type variables. We have also observed outbursts in the cataclysmic variables B7 and B8.
- ID:
- ivo://CDS.VizieR/J/AJ/141/78
- Title:
- Low-mass eclipsing binaries in KIC
- Short Name:
- J/AJ/141/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify 231 objects in the newly released Cycle 0 data set from the Kepler Mission as double-eclipse, detached eclipsing binary systems with Teff<5500K and orbital periods shorter than ~32 days. We model each light curve using the JKTEBOP code with a genetic algorithm to obtain precise values for each system. We identify 95 new systems with both components below 1.0M_{sun}_ and eclipses of at least 0.1mag, suitable for ground-based follow-up. Of these, 14 have periods less than 1.0-day, 52 have periods between 1.0 and 10.0-days, and 29 have periods greater than 10.0-days. This new sample of main-sequence, low-mass, double-eclipse, detached eclipsing binary candidates more than doubles the number of previously known systems and extends the sample into the completely heretofore unexplored P>10.0-day period regime.
- ID:
- ivo://CDS.VizieR/J/AJ/134/1963
- Title:
- MACHO r,b light curves of MC eclipsing binaries
- Short Name:
- J/AJ/134/1963
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new sample of 4634 eclipsing binary stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 eclipsing binary stars in the Small Magellanic Cloud (SMC), that were identified in the light-curve database of the MACHO project. We perform a cross-correlation with the OGLE-II LMC sample, finding 1236 matches. A cross correlation with the OGLE-II SMC sample finds 698 matches. We then compare the LMC subsamples corresponding to the center and periphery of the LMC and find only minor differences between the two populations. These samples are sufficiently large and complete that statistical studies of the binary star populations are possible.
140. MACHO Variables V.
- ID:
- ivo://CDS.VizieR/J/AJ/114/326
- Title:
- MACHO Variables V.
- Short Name:
- J/AJ/114/326
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the characteristics of 611 eclipsing binary stars in the Large Magellanic Cloud found by using the MACHO Project photometry database. The sample is magnitude limited, and extends down the main sequence to about spectral type A0. Many evolved binaries are also included. Each eclipsing binary is classified according to the traditional scheme of the General Catalogue of Variable Stars (EA and EB), and also according to a new decimal classification scheme defined in this paper. The new scheme is sensitive to the two major sources of variance in eclipsing binary star light curves -- the sum of radii, and the surface-brightness ratio, and allow greater precision in characterizing the light curves. Examples of each type of light curve and their variations are given. Sixty-four of the eclipsing binaries have eccentric, rather than circular, orbits. The ephemeris and principal photometric characteristics of each eclipsing binary are listed in a table. Photometric orbits based on the Nelson-Davis-Etzel model have been fitted to all light curves. These data will be useful for planning future observations of these binaries. Plots of all data and fitted orbits and a table of the fitted orbital parameters are available on the AAS CD-ROM series, Vol. 9, 1997. These data are also available at the MACHO home page (http://wwwmacho.mcmaster.ca/). (c) 1997 American Astronomical Society.
