- ID:
- ivo://CDS.VizieR/J/AcA/53/1
- Title:
- OGLE eclipsing binaries in LMC
- Short Name:
- J/AcA/53/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AcA/65/39
- Title:
- OGLE Galactic Bulge ultra-short-period binaries
- Short Name:
- J/AcA/65/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 242 ultra-short-period (Porb<0.22d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve morphology, we divide the sample into candidates for contact binaries and non-contact binaries. In the latter group we distinguish binary systems consisting of a cool main-sequence star and a B-type subdwarf (HW Vir stars) and candidates for cataclysmic variables, including five eclipsing dwarf novae. One of the detected eclipsing binary systems - OGLE-BLG-ECL-000066 - with the orbital period below 0.1d, likely consists of M dwarfs in a nearly contact configuration. If confirmed, this would be the shortest-period M-dwarf binary system currently known. We discuss possible evolutionary mechanisms that could lead to the orbital period below 0.1d in an M-dwarf binary.
- ID:
- ivo://CDS.VizieR/J/AcA/62/33
- Title:
- OGLE II detached red giant eclipsing binary twins
- Short Name:
- J/AcA/62/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify 34 highly-probable detached, red giant eclipsing binary pairs among 315 candidates in Devor's catalog of ~10000 OGLE-II eclipsing binaries. We estimate that there should be at least 200 such systems in OGLE-III. We show that spectroscopic measurements of the metallicities and radial-velocity-derived masses of these systems would independently constrain both the age-metallicity and helium-metallicity relations of the Galactic bulge, potentially breaking the age-helium degeneracy that currently limits our ability to characterize the bulge stellar population.
- ID:
- ivo://CDS.VizieR/J/AcA/63/115
- Title:
- OGLE-III Galactic disk eclipsing binaries
- Short Name:
- J/AcA/63/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of 11589 eclipsing binary stars identified in twenty-one OGLE-III Galactic disk fields toward constellations of Carina, Centaurus, and Musca. All eclipsing binaries but 402 objects are new discoveries. The binaries have out-of-eclipse brightness between I=12.5mag and I=21mag. The completeness of the catalog is estimated at a level of about 75%. Comparison of the orbital period distribution for the OGLE-III disk binaries with systems detected in other recent large-scale Galactic surveys shows the maximum around 0.40d and an almost flat distribution between 0.5d and 2.5d, independent of population. Ten doubly eclipsing systems and one eclipsing-ellipsoidal object were found among thousands of variables. Nine of them are candidates for quadruple systems. We also identify ten eclipsing subdwarf-B type binary stars and numerous eclipsing RS CVn type variables. All objects reported in this paper are part of the OGLE-III Catalog of Variable Stars.
- ID:
- ivo://CDS.VizieR/J/AcA/63/323
- Title:
- OGLE-III SMC eclipsing binary stars
- Short Name:
- J/AcA/63/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large sample of eclipsing binary stars detected in the Small Magellanic Cloud fields covering about 14 square degrees that have been monitored for eight years during the third phase of the OGLE survey. This is the largest set of such variables containing 6138 objects, of which 777 are contact and 5361 non-contact binaries. The estimated completeness of this sample is around 82%. We analyze the statistical properties of the sample and present selected interesting objects: 32 systems having eccentric orbit with visible apsidal motion, one Transient Eclipsing Binary, ten RS CVn type stars, 22 still unexplained Double-Periodic Variable stars, and 15 candidates for doubly eclipsing quadruple systems. Based on the OGLE-III proper motions, we classified 47 binaries from our sample as foreground Galactic stars. We also list candidates suitable for the SMC distance determination.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A125
- Title:
- OGLE-III SMC massive stars VI light curves
- Short Name:
- J/A+A/562/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a variability study of 4646 massive stars in the Small Magellanic Cloud (SMC) with known spectral types from the catalog of Bonanos et al. (2010, Cat. J/AJ/140/416) using the light curves from the OGLE-III database. The goal is to exploit the time domain information available through OGLE-III to gain insight into the processes that govern the evolution of massive stars. This variability survey of massive stars with known spectral types is larger than any previous survey by a factor of 7. We find that 60% of our sample (2766 stars) show no significant variability and 40% (1880 stars) exhibit variability distributed as follows: 807 stars display low-amplitude stochastic variability with fluctuations in I-band of up to 0.05mag, 443 stars present irregular variability of higher amplitude (76% of these are reported as variables for the first time), 205 are eclipsing binaries (including 101 newly discovered systems), 50 are candidate rotating variables, 126 are classical Cepheids, 188 stars exhibit short-term sinusoidal periodicity (P<3-days) making them candidate 'slowly pulsating B stars' and non-radial Be pulsators, and 61 periodic stars exhibit longer periods. We demonstrate the wealth of information provided in the time domain, by doubling the number of known massive eclipsing binary systems and identifying 189 new candidate early-type Be and 20 Oe stars in the SMC. In addition, we find that ~80% of Be stars are photometrically variable in the OGLE-III time domain and provide evidence that short-term pulsating stars with additional photometric variability are rotating close to their break-up velocity.
- ID:
- ivo://CDS.VizieR/J/AcA/54/1
- Title:
- OGLE II SMC eclipsing binaries
- Short Name:
- J/AcA/54/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new version of the OGLE-II catalog of eclipsing binary stars detected in the Small Magellanic Cloud, based on Difference Image Analysis catalog of variable stars in the Magellanic Clouds containing data collected from 1997 to 2000. We found 1351 eclipsing binary stars in the central 2.4 square degree area of the SMC. 455 stars are newly discovered objects, not found in the previous release of the catalog. The eclipsing objects were selected with the automatic search algorithm based on the artificial neural network. The full catalog with individual photometry is accessible from the OGLE INTERNET archive, at ftp://sirius.astrouw.edu.pl/ogle/ogle2/var_stars/smc/ecl . Regular observations of the SMC fields started on June 26, 1997 and covered about 2.4 square degrees of central parts of the SMC. Reductions of the photometric data collected up to the end of May 2000 were performed with the Difference Image Analysis (DIA) package.
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/953
- Title:
- OGLE-LMC-CEP-0227 RV and VI[3.6] curves
- Short Name:
- J/MNRAS/436/953
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A novel method of analysis of double-lined eclipsing binaries containing a radially pulsating star is presented. The combined pulsating-eclipsing light curve is built up from a purely eclipsing light-curve grid created using an existing modelling tool. For every pulsation phase, the instantaneous radius and surface brightness are taken into account, being calculated from the disentangled radial velocity curve of the pulsating star and from its out-of-eclipse pulsational light curve and the light ratio of the components, respectively. The best model is found using the Markov chain Monte Carlo method. The method is applied to the eclipsing binary Cepheid OGLE-LMC-CEP-0227 (P_puls_=3.80d, P_orb_=309d). We analyse a set of new spectroscopic and photometric observations for this binary, simultaneously fitting OGLE V-band, I-band and Spitzer 3.6{mu}m photometry. We derive a set of fundamental parameters of the system significantly improving the precision comparing to the previous results obtained by our group. The Cepheid mass and radius are M_1_=4.165+/-0.032M_{sun}_ and R_1_=34.92+/-0.34R{sun}, respectively. For the first time a direct, geometrical and distance-independent determination of the Cepheid projection factor is presented. The value p=1.21+/-0.03(stat.)+/-0.04(syst.) is consistent with theoretical expectations for a short-period Cepheid and interferometric measurements for {delta} Cep. We also find a very high value of the optical limb darkening coefficients for the Cepheid component, in strong disagreement with theoretical predictions for static atmospheres at a given surface temperature and gravity.
- ID:
- ivo://CDS.VizieR/J/ApJ/868/30
- Title:
- OGLE LMC-T2CEP-211 eclipsing binary LCs and RVs
- Short Name:
- J/ApJ/868/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of a peculiar W Virginis (pWVir) type II Cepheid, OGLE-LMC-T2CEP-211 (P_puls_=9.393d), in a double-lined binary system (P_orb_=242d), which shed light on virtually unknown evolutionary status and structure of pWVir stars. The dynamical mass of the Cepheid (first ever for a type II Cepheid) is 0.64+/-0.02M_{sun}_, and the radius R=25.1+/-0.3R_{sun}_. The companion is a massive (5.67M_{sun}_) main-sequence star obscured by a disk. Such a configuration suggests a mass transfer in the system history. We found that originally the system (P_orb_^init^=12d) was composed of 3.5 and 2.8M_{sun}_ stars, with the current Cepheid being more massive. The system age is now ~200Myr, and the Cepheid is almost completely stripped of hydrogen, with helium mass of ~92% of the total mass. It finished transferring the mass 2.5Myr ago and is evolving toward lower temperatures passing through the instability strip. Comparison with observations indicates a reasonable 2.7x10^-8^M_{sun}_/yr mass loss from the Cepheid. The companion is most probably a Be main-sequence star with T=22000K and R=2.5R_{sun}_. Our results yield a good agreement with a pulsation theory model for a hydrogen-deficient pulsator, confirming the described evolutionary scenario. We detected a two-ring disk (R_disk_~116R_{sun}_) and a shell (R_shell_~9R_{sun}_) around the companion, which is probably a combination of the matter from the past mass transfer, the mass being lost by the Cepheid owing to wind and pulsations, and a decretion disk around a rapidly rotating secondary. Our study, together with observational properties of pWVir stars, suggests that the majority of them are products of a similar binary evolution interaction.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A45
- Title:
- 1995-2000 optical spectra of CH Cyg
- Short Name:
- J/A+A/622/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CH Cyg is one of the most studied symbiotic stars. Its properties, however, are still not well known. Two main periods, about 15 years and 750-days, are known in the photometric and spectroscopic variations, and two models are proposed for these origins. One is a binary system with an orbital period of 15 years consisting of a hot component and pulsating red giant with a 750-day period. The other is a triple system consisting of an inner symbiotic binary with an orbital period of about 750-days and third component with an orbital period of 15 years. Several active stages have been observed since the 1970s during which the object brightened up by {Delta}U=3-5mag and prominent emission lines appeared. Large mass outflows were observed at some active stages. The spectral variation of CH Cyg has been monitored at Asiago Observatories to understand the problems mentioned above. We have analysed spectra obtained in the time period from 1995 to 2004 which covers an active stage during the years 1998-2000. High- and low-resolution optical spectra obtained at the Asiago Observatories are used. Narrow absorption lines of FeI, CrI, TiI, and so on appeared in 1998 at an early phase of the active stage. These lines are clearly distinguished from those of the M-type giant and are typically found on the spectrum of early A-type dwarfs. They were redshifted by about 30km/s, with respect to the absorption lines of the M-type giant. Assuming that their radial velocities represent the orbital motion of the hot component, its semi-amplitude is estimated to be 37.0+/60.5km/s.
