- ID:
- ivo://CDS.VizieR/J/AJ/134/179
- Title:
- Ligth minimum times of TY Boo
- Short Name:
- J/AJ/134/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed period analysis of TY Bootis, based on all available light minimum times covering about 80 years. We discovered that there exists a cyclic variation overlaying a secular period decrease from the distorted (O-C) diagram. A long-term decrease with a sinusoidal oscillation (i.e., eq. (2)) or with a light-time effect (i.e., eq. (3)) may be reasonable due to the smaller difference between their sum of residuals. The sinusoidal change with a period of 59.7 yr for equation (2) can be attributed to either a light-time effect or cyclic magnetic activity of both components. For the assumed third body, the period and eccentricity of the light-time orbit are P_3_=58.6yr and e'=0.1744, respectively. If the existence of an additional unseen body is true, this binary may be a tertiary system. The long-term orbital period decrease suggests that TY Boo is undergoing a mass transfer from the primary component to the secondary component at a rate of dm/dt=-3.15x10^-8^M_{sun}_/yr for equation (2) or dm/dt=-2.90x10^-8^M_{sun}_/yr for equation (3). As its mass transfers, accompanied by angular momentum loss due to mass outflow L_2_, this binary will evolve into a deep contact configuration.
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- ID:
- ivo://CDS.VizieR/J/ApJ/766/3
- Title:
- Limb-darkening coefficients for eclipsing WD*
- Short Name:
- J/ApJ/766/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive calculations of linear and nonlinear limb-darkening coefficients as well as complete intensity profiles appropriate for modeling the light-curves of eclipsing white dwarfs. We compute limb-darkening coefficients in the Johnson-Kron-Cousins UBVRI photometric system as well as the Large Synoptic Survey Telescope (LSST) ugrizy system using the most up to date model atmospheres available. In all, we provide the coefficients for seven different limb-darkening laws. We describe the variations of these coefficients as a function of the atmospheric parameters, including the effects of convection at low effective temperatures. Finally, we discuss the importance of having readily available limb-darkening coefficients in the context of present and future photometric surveys like the LSST, Palomar Transient Factory, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The LSST, for example, may find ~10^5^ eclipsing white dwarfs. The limb-darkening calculations presented here will be an essential part of the detailed analysis of all of these systems.
- ID:
- ivo://CDS.VizieR/J/A+A/335/647
- Title:
- Limb-darkening coefficients for ubvyUBVRIJHK
- Short Name:
- J/A+A/335/647
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Linear and non-linear limb-darkening coefficients for the photometric bands u v b y U B V R I J H K are computed for very low effective temperatures stars. The atmosphere models used (PHOENIX-NextGen) do not include the effects of dust formation and dust opacities. These calculations are presented for the first time . The calculations extend the range of effective temperatures (2000K-50000K) covered by our previous papers. These data are important in order to deal with stars in the lower part of Main-Sequence like M or brown dwarfs. The non-linear behavior of the limb-darkening laws, particularly in this effective temperature range, is emphasized and we urge users to take it into account.
- ID:
- ivo://CDS.VizieR/J/AJ/106/2096
- Title:
- Limb-darkening coefficients in binaries
- Short Name:
- J/AJ/106/2096
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present monochromatic, passband-specific, and bolometric limb-darkening coefficients for a linear as well as nonlinear logarithmic and square root limb-darkening laws. These coefficients, including the bolometric ones, are needed when modeling binary star light curves with the latest version of the Wilson-Devinney light curve program. We base our calculations on the most recent ATLAS stellar atmosphere models for solar chemical composition stars with a wide range of effective temperatures and surface gravities. We examine how well various limb-darkening approximations represent the variation of the emerging specific intensity across a stellar surface as computed according to the model. For binary star light curve modeling purposes, we propose the use of a logarithmic or a square root law. We design our tables in such a manner that the relative quality of either law with respect to another can be easily compared. Since the computation of bolometric limb-darkening coefficients first requires monochromatic coefficients, we also offer tables of these coefficients (at 1221 wavelength values between 0.09 nm and 160 {mu}m) and tables of passband-specific coefficients for commonly used photometric filters.
- ID:
- ivo://CDS.VizieR/J/AJ/158/104
- Title:
- LL Com BVR bands photometry & times of light minimum
- Short Name:
- J/AJ/158/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Despite the discovery of LL Com, a Lyrae-type eclipsing binary system, approximately 60 yr ago, little has been found concerning its detailed photometry and orbital-period change until now. In this paper, we present the first multi-band charge-coupled-device photometric light curves, from which a significant luminosity reduction around the primary eclipse is revealed. Based on LAMOST data, we first determined LL Com's spectrum as F1V and then analyzed the light curves with the 2015 version of the Wilson-Devinney code. The fact that LL Com is a near-contact binary system with a semi-detached configuration, where the secondary component only fills its Roche lobe and the primary component fills more than 95% of its Roche lobe, is suggested through the photometric solution. In addition, according to archival photometry and previously published times of minima, a secular period increase at a rate of P=2.62x10^-7^ day/yr was found, which implies a continuous mass transfer from the secondary to the primary. Utilizing the photometric solution and the simulations of single-particle trajectories, we propose the existence of a cool spot on the surface of the primary component. This cool spot can be naturally produced by the impacts that occur during mass flow, and it also successfully interprets the luminosity reduction in the light curves. Finally, with the combination of thermal relaxation oscillation theory and the Roche-Lobe model, we conclude that LL Com is transitioning from the semi-detached to the detached phase.
- 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/ApJ/839/39
- Title:
- Long-term CCD photometry of the EB 2M1533+3759
- Short Name:
- J/ApJ/839/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometry of seven successive years from 2010 is presented for the HW Vir-type eclipsing binary 2M 1533+3759. Using the VI light curves together with the radial-velocity data given by For+ (2010ApJ...708..253F), we determined the absolute parameters of each component to be M1=0.442+/-0.012M{sun}, M2=0.124+/-0.005M{sun}, R1=0.172+/-0.002R{sun}, R2=0.157+/-0.002R{sun}, L1=19.4+/-1.4L{sun}, and L2=0.002+/-0.002L{sun}. These indicate that 2M 1533+3759 is a detached system consisting of a normal sdB primary and an M7 dwarf companion. Detailed analyses of 377 minimum epochs, including our 111 timings, showed that the orbital period of the system remains constant during the past 12 years. Inspecting both types of minima, we found a delay of 3.9+/-1.0s in the arrival times of the secondary eclipses relative to the primary eclipse times. This delay is in satisfactory agreement with the predicted Romer delay of 2.7+/-1.4s, and the result is the second measurement in sdB+M eclipsing binaries. The time shift of the secondary eclipse can be explained by some combination of the Romer delay and a non-zero eccentricity. Then the binary star would have a very small eccentricity of e.cos{omega}~0.0001.
- ID:
- ivo://CDS.VizieR/J/PAZh/41/303
- Title:
- Long-term monitoring of SZ Cam
- Short Name:
- J/PAZh/41/303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the reduction of our photometric and spectroscopic observations for the eclipsing binary SZ Cam performed with the telescopes at the Astronomical Observatory of the Ural Federal University and the Special Astrophysical Observatory of the Russian Academy of Sciences in 1996-2014. Based on an 11-year-long photometric monitoring of SZ Cam, we have obtained new elements of its photometric orbit and parameters of its components. We have detected low-amplitude periodic light variations in SZ Cam that are possibly related to the ellipsoidal shape of the components of the spectroscopic binary third body.
- ID:
- ivo://CDS.VizieR/J/AJ/148/37
- Title:
- Long-term photometric behavior of V404 Lyr
- Short Name:
- J/AJ/148/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the physical properties of V404 Lyr exhibiting eclipse timing variations and multiperiodic pulsations from all historical data including the Kepler and SuperWASP observations. Detailed analyses of 2922 minimum epochs showed that the orbital period has varied through a combination of an upward-opening parabola and two sinusoidal variations, with periods of P_3_=649days and P_4_=2154days and semi-amplitudes of K_3_=193s and K_4_=49s, respectively. The secular period increase at a rate of +1.41x10^-7^days/yr could be interpreted as a combination of the secondary to primary mass transfer and angular momentum loss. The most reasonable explanation for both sinusoids is a pair of light-travel-time effects due to two circumbinary objects with projected masses of M_3_=0.47M_{sun}_ and M_4_=0.047M_{sun}_. The third-body parameters are consistent with those calculated using the Wilson-Devinney binary code. For the orbital inclinations i_4_>~43{deg}, the fourth component has a mass within the hydrogen-burning limit of ~0.07M_{sun}_, which implies that it is a brown dwarf. A satisfactory model for the Kepler light curves was obtained by applying a cool spot to the secondary component. The results demonstrate that the close eclipsing pair is in a semi-detached, but near-contact, configuration; the primary fills approximately 93% of its limiting lobe and is larger than the lobe-filling secondary. Multiple frequency analyses were applied to the light residuals after subtracting the synthetic eclipsing curve from the Kepler data. This revealed that the primary component of V404 Lyr is a {gamma} Dor type pulsating star, exhibiting seven pulsation frequencies in the range of 1.85-2.11/day with amplitudes of 1.38-5.72mmag and pulsation constants of 0.24-0.27days. The seven frequencies were clearly identified as high-order low-degree gravity-mode oscillations which might be excited through tidal interaction. Only eight eclipsing binaries have been known to contain {gamma} Dor pulsating components and, therefore, V404 Lyr will be an important test bed for investigating these rare and interesting objects.
