- ID:
- ivo://CDS.VizieR/J/ApJ/664/1154
- Title:
- Light curve of 2MASS J05352184-0546085
- Short Name:
- J/ApJ/664/1154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The newly discovered brown dwarf eclipsing binary 2MASS J05352184-0546085 provides a unique laboratory for testing the predictions of theoretical models of brown dwarf formation and evolution. The finding that the lower mass brown dwarf in this system is hotter than its higher mass companion represents a challenge to brown dwarf evolutionary models, none of which predict this behavior. Here we present updated determinations of the basic physical properties of 2M0535-05, bolstering the surprising reversal of temperatures with mass in this system. We compare these measurements with widely used brown dwarf evolutionary tracks, and find that the temperature reversal can be explained by some models if the components of 2M0535-05 are mildly non-coeval, possibly consistent with dynamical simulations of brown dwarf formation. Alternatively, a strong magnetic field on the higher mass brown dwarf might explain its anomalously low surface temperature, consistent with emerging evidence that convection is suppressed in magnetically active, low-mass stars. Finally, we discuss future observational and theoretical work needed to further characterize and understand this benchmark system.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/520/A73
- Title:
- Light curve of V945 Cen in Geneva photometry
- Short Name:
- J/A+A/520/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed analysis of multicolour Geneva photometry and high-resolution echelle spectroscopy of the B8.5V star V945 Cen (HD 112409, V=5.2mag) whose short-term periodic variability was first detected from the HIPPARCOS data, led to the finding that the object is an ellipsoidal variable and a close double-lined spectroscopic binary with a 0.6496d orbital period and a circular orbit. The components have spectral types B7 and B8.5 and are both main-sequence objects. The system is detached but close to a contact configuration and is observed at an inclination of ~23-24{deg}. A notable finding is that the optical spectrum also contains a third system of spectral lines corresponding to a late B spectral type that remained stationary during the 5 days of spectral observations. From several independent lines of reasoning, we tentatively conclude that the third spectrum belongs to a real third body in the system. However, the possibility that it instead originates in circumbinary gas cannot be excluded completely, and additional spectral and interferometric observations are required to help us determine its origin conclusively.
- ID:
- ivo://CDS.VizieR/J/MNRAS/506/2122
- Title:
- Light curves and eclipse times of HW Vir
- Short Name:
- J/MNRAS/506/2122
- Date:
- 17 Jan 2022 00:24:15
- Publisher:
- CDS
- Description:
- A growing number of eclipsing binary systems of the HW Virginis (HW Vir) kind (i.e. composed by a subdwarf-B/O primary star and an M dwarf secondary) show variations in their orbital period, also called eclipse time variations (ETVs). Their physical origin is not yet known with certainty: While some ETVs have been claimed to arise from dynamical perturbations due to the presence of circumbinary planetary companions, other authors suggest that the Applegate effect or other unknown stellar mechanisms could be responsible for them. In this work, we present 28 unpublished high-precision light curves of one of the most controversial of these systems, the prototype HW Vir. We homogeneously analysed the new eclipse timings together with historical data obtained between 1983 and 2012, demonstrating that the planetary models previously claimed do not fit the new photometric data, besides being dynamically unstable. In an effort to find a new model able to fit all the available data, we developed a new approach based on a global-search genetic algorithm and eventually found two new distinct families of solutions that fit the observed timings very well, yet dynamically unstable at the 10^5^-yr time-scale. This serves as a cautionary tale on the existence of formal solutions that apparently explain ETVs but are not physically meaningful, and on the need of carefully testing their stability. On the other hand, our data confirm the presence of an ETV on HW Vir that known stellar mechanisms are unable to explain, pushing towards further observing and modeling efforts.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A46
- Title:
- Light curves 0f 6 MC eclipsing binaries
- Short Name:
- J/A+A/609/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to present a novel method to determine compact triples using publicly available photometric data from large surveys. Here we apply it to eclipsing binaries (EBs) in Magellanic Clouds from OGLE III database. Our tool consists of identifying the cases where the orbital plane of EB evolves in accord with expectations from the interaction with a third star. We analyzed light curves (LCs) of 26121 LMC and 6138 SMC EBs with the goal to identify those for which the orbital inclination varies in time. Archival LCs of the selected systems, when complemented by our own observations with Danish 1.54-m telescope, were thoroughly analyzed using the PHOEBE program. This provided physical parameters of components of each system. Time dependence of the EB inclination was described using the theory of orbital-plane precession. By observing the parameter-dependence of the precession rate, we were able to constrain the third companion mass and its orbital period around EB.
- ID:
- ivo://CDS.VizieR/J/MNRAS/476/5253
- Title:
- Light curves for 5 LMEBs in WFCAM Transit Survey
- Short Name:
- J/MNRAS/476/5253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the light curves of the 5 low-mass eclipsing binaries (LMEBs) from the WFCAM Transit Survey (WTS) reported in the paper. These light curves, along with additional spectroscopic data, were simultaneously adjusted to obtain orbital parameters and fundamental properties of the components of each binary system. The obtained results revealed components with inflated radii when compared to evolutionary models.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A25
- Title:
- Light curves for the eclipsing binary V1094 Tau
- Short Name:
- J/A+A/578/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V1094 Tau is a bright eclipsing binary star with an orbital period close to 9 days containing two stars similar to the Sun. Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau. We present new spectroscopy of V1094 Tau which we use to estimate the effective temperatures of both stars and to refine their spectroscopic orbits. We also present new, high-quality photometry covering both eclipses of V1094 Tau in the Stroemgren uvby system and in the Johnson V-band. The masses, radii and effective temperatures of the stars in V1094 Tau are found to be M_A_=1.0965+/-0.0040M_{sun}_, R_A_=1.4109+/-0.0058R_{sun}_, T_eff,A_=5850+/-100K, and M_B_=1.0120+/-0.0028M_{sun}_, R_B_=1.1063+/-0.0066R_{sun}_, T_eff,B_=5700+/-100K. An analysis of the times of mid-eclipse and the radial velocity data reveals apsidal motion with a period of 14500+/-3700-years. The observed masses, radii and effective temperatures are consistent with stellar models for an age ~6Gyr if the stars are assumed to have a metallicity similar to the Sun. This estimate is in reasonable agreement with our estimate of the metallicity derived using Stroemgren photometry and treating the binary as a single star ([Fe/H]=-0.09+/-0.11). The rotation velocities of the stars suggest that V1094 Tau is close to the limit at which tidal interactions between the stars force them to rotate pseudo-syncronously with the orbital motion.
- ID:
- ivo://CDS.VizieR/J/AJ/143/13
- Title:
- Light curves of AL Gem and BM Mon
- Short Name:
- J/AJ/143/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the CCD photometry of two Algol-type binaries, AL Gem and BM Mon, observed from 2008 November to 2011 January. With the updated Wilson-Devinney program, photometric solutions were deduced from their EA-type light curves. The mass ratios and fill-out factors of the primaries are found to be q_ph_=0.090(+/-0.005) and f_1_=47.3%(+/-0.3%) for AL Gem, and q_ph_=0.275(+/-0.007) and f_1_=55.4%(+/-0.5%) for BM Mon, respectively. By analyzing the O-C curves, we discovered that the periods of AL Gem and BM Mon change in a quasi-sinusoidal mode, which may possibly result from the light-time effect via the presence of a third body. Periods, amplitudes, and eccentricities of light-time orbits are 77.83(+/-1.17)yr, 0.0204(+/-0.0007)d, and 0.28(+/-0.02) for AL Gem and 97.78(+/-2.67)yr, 0.0175(+/-0.0006)d, and 0.29(+/-0.02) for BM Mon, respectively. Assumed to be in a coplanar orbit with the binary, the masses of the third bodies would be 0.29M_{sun}_ for AL Gem and 0.26M_{sun}_ for BM Mon. This kind of additional companion can extract angular momentum from the close binary orbit, and such processes may play an important role in multiple star evolution.
- ID:
- ivo://CDS.VizieR/J/AJ/147/35
- Title:
- Light curves of Algol-type binaries. VI. FR Ori
- Short Name:
- J/AJ/147/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New photometry of the neglected eclipsing binary FR Orionis was obtained in 2012 November and December. Using the updated Wilson-Devinney program, the photometric elements were deduced from two-color light curves. The results indicate that this system is a semi-detached binary, with a mass ratio of 0.325(+/-0.002) and a fill-out factor of the primary of f_p_=73.5(+/-0.2)%. The oscillating light curves imply that FR Ori may be an oscillating EA (oEA)-type star with a rapidly pulsating, mass-accreting primary component. After we removed the theoretical light curves from the observations, Fourier analysis revealed that the more massive component possibly shows a {delta} Scuti type pulsation with four detected frequencies. The dominant frequency is f_1_=38.6c/day (i.e., P_puls_=37.3minutes), and the pulsation constant is Q=0.014days. Based on all available eclipsing times, the orbital period is undergoing a secular period increase with a rate of dP/dt=+8.85(+/-0.66)x10^-8^day/yr, which may be interpreted by mass transfer from the secondary to the primary. We expect that the more massive component will fill its Roche lobe due to mass transfer of the secondary. Therefore, the oEA star FR Ori may evolve into a contact configuration.
- ID:
- ivo://CDS.VizieR/J/AJ/147/66
- Title:
- Light curves of Algol-type binaries. VII. V404 And
- Short Name:
- J/AJ/147/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new CCD light curves of the short-period Algol-type eclipsing binary V404 And obtained in 2009-2011. The time-resolving multiple BVRI color light curves of the year 2011 with full phase coverage were analyzed simultaneously using the latest Wilson-Devinney program. We concluded that the configuration of two starspots on the primary is the most reliable explanation for the light curve distortions observed in 2011. Based on the new photometric solution, we further applied the spot model to explain the other light curves, including the previously published R-band light curves. We revealed that the starspots changed on a long timescale in terms of the spot parameters and the differences between Max.I and Max.II. Moreover, the O-C diagram spanning about 15yr shows an upward parabola, which indicates a secular increase in the orbital period of V404 And. The orbital period increases at a rate of dP/dt=5.3(0.3)x10^-7^days/yr, which might be interpreted by the angular momentum exchange via magnetic activity.
- ID:
- ivo://CDS.VizieR/J/other/NewA/34.253
- Title:
- Light curves of 8 Algol-type systems
- Short Name:
- J/other/NewA/34.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Analyzing available photometry from the Super WASP and other databases, we performed the very first light curve analysis of eight eclipsing binary systems V537 And, GS Boo, AM CrB, V1298 Her, EL Lyn, FW Per, RU Tri, and WW Tri. All of these systems were found to be detached ones of Algol-type, having the orbital periods of the order of days. 722 new times of minima for these binaries were derived and presented, trying to identify the period variations caused by the third bodies in these systems.
