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- ID:
- ivo://CDS.VizieR/J/AJ/117/2980
- Title:
- NIR photometric studies of R Canis Majoris
- Short Name:
- J/AJ/117/2980
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the first light curves of the peculiar Algol binary system R Canis Majoris obtained in the near-infrared photometric bands J and K. The light curves are fitted for a semidetached model with the Wilson-Devinney light-curve synthesis program. Five epochs of primary minima and four epochs of secondary minima are obtained in the present study. The increased depth of the secondary minima in the near-IR bands compared with the optical bands enabled us to determine the moments of secondary minima with nearly the same accuracy as those of primary minima. All the secondary minima appear at phase 0.5, and the durations are equal for the primary and the secondary eclipses. The epochs of primary minima follow the nearly sinusoidal O-C curve that has been observed for this star in previous studies. The values of O-C for the secondary minima were in the same range as those of the primary minima observed by us.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A153
- Title:
- NSVS 10653195 light and velocity curves
- Short Name:
- J/A+A/627/A153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-mass stars in eclipsing binary systems show radii larger and effective temperatures lower than theoretical stellar models predict for isolated stars with the same masses. Eclipsing binaries with low-mass components are hard to find due to their low luminosity. As a consequence, the analysis of the known low-mass eclipsing systems is key to understand this behavior. We aim to investigate the mass-radius relation for low-mass stars and the cause of the deviation of the observed radii in low-mass detached eclipsing binary stars (LMDEB) from theoretical stellar models. We developed a physical model of the LMDEB system NSVS 10653195 to accurately measure the masses and radii of the components. We obtained several high-resolution spectra in order to fit a spectroscopic orbit. Standardized absolute photometry was obtained to measure reliable color indices and to measure the mean Teff of the system in out-of-eclipse phases. We observed and analyzed optical VRI and infrared JK band differential light-curves which were fitted using PHOEBE. A Markov-Chain Monte Carlo (MCMC) simulation near the solution found provides robust uncertainties for the fitted parameters. NSVS 10653195 is a detached eclipsing binary composed of two similar stars with masses of M1=0.6402+/-0.0052M_{sun}_ and M2=0.6511+/-0.0052M_{sun}_ and radii of R1=0.687^+0.017^_-0.024_R_{sun}_ and R2=0.672^+0.018^_-0.022_R_{sun}_. Spectral types were estimated to be K6V and K7V. These stars rotate in a circular orbit with an orbital inclination of i=86.22+/-0.61 degrees and a period of P=0.5607222(2)d. The distance to the system is estimated to be d=135.2^+7.6^_-7.9_pc, in excellent agreement with the value from Gaia. If solar metallicity were assumed, the age of the system would be older than log(age)~8 based on the M_bol_-logTeff diagram. NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their Teff are in better agreement with models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/1141
- Title:
- NSVS 06507557 VRI differential photometry
- Short Name:
- J/MNRAS/401/1141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the results of a detailed spectroscopic and photometric analysis of the V=13.4mag low-mass eclipsing binary NSVS 06507557 with an orbital period of 0.515d. We have obtained a series of mid-resolution spectra covering nearly the entire orbit of the system. In addition, we have obtained simultaneous VRI broad-band photometry using a small aperture telescope. From these spectroscopic and photometric data, we have derived the system's orbital parameters and we have determined the fundamental stellar parameters of the two components. Our results indicate that NSVS 06507557 consists of a K9 pre-main-sequence star and an M3 pre-main-sequence star.
- ID:
- ivo://CDS.VizieR/J/AJ/157/184
- Title:
- NY Virginis primary mid-eclipse times
- Short Name:
- J/AJ/157/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 18 new primary minima timing observations of the short-period eclipsing binary system NY Virginis. We combined these minima with previously published primary minima to update circumbinary exoplanet models in this system based on O-C timing variations. We performed a nonlinear least-squares minimization search using a quadratic ephemeris and either one or two exoplanets. The only model with an acceptable fit includes a period derivative P=2.83x10^-12^ and two planets in eccentric orbits e=0.15, 0.15 with minimum masses of 2.7 and 5.5 Jovian masses. Analysis of the orbit stability shows that this solution is stable for at least 10^8^ years, but a small increase in eccentricity (e>=0.20) for either planet renders the orbits unstable in less than 10^6^ years. A number of model parameters are significantly degenerate, so additional observations are required to determine planetary parameters with high statistical confidence.
- ID:
- ivo://CDS.VizieR/J/AJ/155/177
- Title:
- Obliquities of planetary & eclipsing binary systems
- Short Name:
- J/AJ/155/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The light curve of an eclipsing system shows anomalies whenever the eclipsing body passes in front of active regions on the eclipsed star. In some cases, the pattern of anomalies can be used to determine the obliquity {Psi} of the eclipsed star. Here we present a method for detecting and analyzing these patterns, based on a statistical test for correlations between the anomalies observed in a sequence of eclipses. Compared to previous methods, ours makes fewer assumptions and is easier to automate. We apply it to a sample of 64 stars with transiting planets and 24 eclipsing binaries for which precise space-based data are available, and for which there was either some indication of flux anomalies or a previously reported obliquity measurement. We were able to determine obliquities for 10 stars with hot Jupiters. In particular we found {Psi}~<10{deg} for Kepler-45, which is only the second M dwarf with a measured obliquity. The other eight cases are G and K stars with low obliquities. Among the eclipsing binaries, we were able to determine obliquities in eight cases, all of which are consistent with zero. Our results also reveal some common patterns of stellar activity for magnetically active G and K stars, including persistently active longitudes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2890
- Title:
- Observation of six NSVS eclipsing binaries
- Short Name:
- J/MNRAS/448/2890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out photometric and low-resolution spectral observations of six eclipsing ultrashort-period binaries with main-sequence (MS)components. The light-curve solutions of the Rozhen observations show that all targets are overcontact systems. We found a well-defined empirical relation between period and semi-major axis for the short-period binaries and used it for estimation of the global parameters of the targets. Our results revealed that NSVS 925605 is quite an interesting target: (i) it is one of a few contact binaries with M components; (ii) it exhibits high activity (emission in the H{alpha} line, X-ray emission, large cool spots, non-Planck energy distribution); (iii) its components differ in temperature by 700 K. All the appearances of high magnetic activity and the huge fill-out factor (0.7) of NSVS 925605 may be a precursor of the predicted merging of close magnetic binaries. Another unusual binary is NSVS 2700153, which reveals considerable long-term variability.
- ID:
- ivo://CDS.VizieR/J/AJ/134/2353
- Title:
- Observations of contact binaries
- Short Name:
- J/AJ/134/2353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of the Canada-France-Hawaii Telescope adaptive optics (AO) search for companions of a homogeneous group of contact binary stars, as a contribution to our attempts to prove the hypothesis that these binaries require a third star to become as close as observed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/314
- Title:
- Observing log of the eclipsing binary SZ Piscium
- Short Name:
- J/MNRAS/456/314
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first Doppler images of the active eclipsing binary system SZ Psc, based on the high-resolution spectral data sets obtained in 2004 November and 2006 September-December. The least-squares deconvolution technique was applied to derive high signal-to-noise profiles from the observed spectra of SZ Psc. Absorption features contributed by a third component of the system were detected in the LSD profiles at all observed phases. We estimated the mass and period of the third component to be about 0.9 M_{sun}_ and 1283+/-10 d, respectively. After removing the contribution of the third body from the least-squares deconvolved profiles, we derived the surface maps of SZ Psc. The resulting Doppler images indicate significant star-spot activities on the surface of the K subgiant component. The distributions of star-spots are more complex than that revealed by previous photometric studies. The cooler K component exhibited pronounced high-latitude spots as well as numerous low- and intermediate-latitude spot groups during the entire observing seasons, but did not show any large, stable polar cap, different from many other active RS CVn-type binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/439/559
- Title:
- OGLE eclipsing binaries (bulge+lmc+smc)
- Short Name:
- J/A+A/439/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 222000 I-band light curves of variable stars detected by the OGLE-II survey (ftp://bulge.princeton.edu/ogle/ogle2/bulge_dia_variables) in the direction of the Galactic Bulge have been searched for eclipsing binaries (EBs). A previously developed code to analyze lightcurve shapes and identify long period variables (LPVs) has been adapted to identify EBs. The parameters in the modified code have been optimised to recover a list of about 140 detached EBs in the Small Magellanic Cloud previously identified in the literature as particularly well suited for distance estimates (and which have periods more than 0.85 days). The power of the code is demonstrated by identifying 16 and 178 previously uncatalogued EBs in the SMC and LMC, respectively. Among the 222 000 variable stars in the direction of the Galactic Bulge 3053 EBs have been identified. Periods and phased lightcurves are presented.
