- ID:
- ivo://CDS.VizieR/J/AJ/156/220
- Title:
- V, R and I light curves of 4 new low-mass M-type EBs
- Short Name:
- J/AJ/156/220
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed multicolor photometric and spectroscopic observations of four new low-mass M-type eclipsing binaries (HAT 225-03429, CRTS J085623.0+282620, CRTS J110302.4+201611, 2MASS J16344899+3716423) in 2017. We obtained new VRI light curves and minimum times of these four systems. Based on our minimum times, we updated the orbital periods and the linear ephemerides using the least squares method. We analyzed these four systems using the Wilson-Devinney program, and obtained the orbital and starspot parameters. The results of our analysis of the light curves indicate that HAT 225-03429 and CRTS J085623.0+282620 are detached eclipsing binaries, CRTS J110302.4+201611 is a semi-detached eclipsing binary, and 2MASS J16344899+3716423 is a contact binary. We performed LAMOST spectroscopic studies of chromospheric activity indicators (H{alpha}, H{beta}, H{gamma}, H{delta}, and Ca II H&K lines) for these four systems for the first time. We first determined their spectral types and calculated the equivalent widths of their chromospheric active indicators. These indicators show that the four low-mass M-type eclipsing binaries are active. Furthermore, the radii of these stars are notably larger than model predictions for their masses, except for the secondary component of HAT 225-03429 and the primary component of CRTS J110302.4+201611.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/417/745
- Title:
- V(RI)C differential photometry of V861 Her
- Short Name:
- J/A+A/417/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- First Cousins V(RI)_C_ light curves of the W UMa-type eclipsing variable star V861 Herculis are presented. The system was observed in 2000 and 2003. The light curves obtained at different epochs showed significant deviation from each other. The O'Connell effect (usually explained by spots on the surface which are responsible for variations in the intensity of the system) was about {Delta}V=0.05mag in 2000 but it vanished in 2003 (except the night of February 22/23, 2003 when we observed a small O'Connell effect ({Delta}V=0.020)). Further peculiarities of the light curves are also discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/132/960
- Title:
- V(RI)c light-curves of EQ Tauri
- Short Name:
- J/AJ/132/960
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New V, R_C_, and I_C_ light curves of EQ Tau have been obtained in 2002 and 2003. These show the secondary minimum to be a total eclipse. These new light curves have been analyzed, together with the published radial velocity observations, using the Wilson-Devinney code. The binary has an overcontact configuration, with an orbital inclination of 85{deg}, a difference in component temperature of 80K, and an overcontact fill-out factor of 16%. Absolute parameters of the component stars have been determined: M1=1.28M_{sun}_, R1=1.17R_{sun}_, L1=1.39 L_{sun}_, and M2=0.47M_{sun}_, R2=0.81R_{sun}_, L2=0.63L_{sun}_. The calculated distance is 180+/-20pc. A critical review of our new timings of minimum light together with previously published ones suggests a change from one constant period to another one around 1974 rather than a cyclical variation. When corrected for energy transfer in the common envelope, the physical parameters of the two components are in good agreement with those of unevolved single stars of similar masses.
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/2620
- Title:
- VRI light curve of 5 eclipsing binaries
- Short Name:
- J/MNRAS/442/2620
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 15 new VRI light curves of five low-mass eclipsing binaries (NSVS 02502726, NSVS 07453183, NSVS 11868841, NSVS 06550671 and NSVS 10653195) that were observed between 2010 and 2012. We analysed our new data together with three published spectroscopic observations and seven published light curves using a modified version of the Wilson-Devinney program. Orbital solutions of the five low-mass eclipsing binaries were revised and new star-spot parameters were obtained. We found that spot locations on the five low-mass eclipsing binaries changed over several years. However, the star-spots for NSVS 07453183 and NSVS 06550671 were stable for several months. More interestingly, for NSVS 02502726, the spots within a star-spot longitude region of 180{deg}-360{deg} indicated a magnetic activity cycle of 5.9(+/-0.2)yr. Moreover, we detected the first flare-like event on NSVS 07453183 at phase 0.39. The observations of the chromospheric activity indicators (H{beta} and H{gamma} lines) revealed that NSVS 10653195 and NSVS 06550671 were active. For NSVS 02502726, we found a weak continuous secular decrease at a smaller rate of dp/dt=-2.1(0.8)x10^-7^d/yr than the previous result. For NSVS 07453183, the O-C times appeared to increase at cycle 6000, and this was followed by a decrease at cycle 6500.
- ID:
- ivo://CDS.VizieR/J/AJ/152/57
- Title:
- VRI light curves of four contact binaries
- Short Name:
- J/AJ/152/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, high-quality multicolor observations of four recently discovered contact binaries, 1SWASP J064501.21+342154.9, 1SWASP J155822.10-025604.8, 1SWASP J212808.86+151622.0, and UCAC4 436-062932, and analyze their light curves to determine orbital and physical parameters using the modeling program of G. Djurasevic. In the absence of spectroscopic observations, the effective temperatures of the brighter components are estimated from the color indices, and the mass ratios are determined with the q-search method. The analysis shows that all four systems are W UMa type binaries in shallow contact configurations, consisting of late-type main-sequence primaries and evolved secondaries with active surface regions (dark or bright spots) resulting from magnetic activity or ongoing transfer of thermal energy between the components. We compare the derived orbital and stellar parameters for these four variables with a large sample of previously analyzed W UMa stars and find that our results fit it well.
- ID:
- ivo://CDS.VizieR/J/AJ/150/9
- Title:
- VRI light curves of GSC 1537-1557
- Short Name:
- J/AJ/150/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By analyzing R_c_ and I_c_light curves of the short-period solar-type eclipsing binary GSC 1537-1557 we discovered that it is a shallow contact binary with a degree of contact factor of f=(8.1+/-1.79)%. Photometric solutions reveal that GSC 1537-1557 is a W-type system with a mass ratio of q=M_2_/M_1_=2.645 where the less massive component (the primary star) is about 110K hotter than the more massive one (the secondary star). The asymmetry and variation of the light curves were explained as the activity of spots on the solar-type component stars. By investigating all of the available times of light minima, we found that the observed-calculated (O-C) curve shows a cyclic variation with a small amplitude of 0.00335days and a period of 8.1years. The small-amplitude cyclic change in the O -C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion. The mass of the third body was determined to be M_3_sini'=(0.19+/-0.01)M_{sun}_ when M_1_+M_2_=1.31M_{sun}_ is adopted for GSC 1537-1557. The semimajor axis of the outer obit is a'sini'=(4.58+/-0.33)AU.
- ID:
- ivo://CDS.VizieR/J/ApJ/783/35
- Title:
- VRI light curves of TT Her
- Short Name:
- J/ApJ/783/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocities and photometry of the short-period Algol TT Herculis. Previous attempts to model the light curves of the system have met with limited success, primarily because of the lack of a reliable mass ratio. Our spectroscopic observations are the first to result in radial velocities for the secondary star, and thus provide a spectroscopic mass ratio. Simultaneous analysis of the radial velocities and new photometry shows that the system is a double contact binary, with a rapidly rotating primary that fills its limiting lobe.
- ID:
- ivo://CDS.VizieR/J/AJ/128/846
- Title:
- VRI observations of CE Leonis
- Short Name:
- J/AJ/128/846
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present complete VRI light curves of the contact binary CE Leo and provide detailed photometric solutions, as well as an analysis of its period variation. A total of 73 times of minima over 50years, including our observations, were used for the period study.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2252
- Title:
- VRI photometry of V410 Aur
- Short Name:
- J/AJ/130/2252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The complete charge-coupled device (CCD) light curves in the V, R, and I bands for the eclipsing binary V410 Aur were observed at the Yunnan Observatory in China.
- ID:
- ivo://CDS.VizieR/J/AJ/143/122
- Title:
- VR light curves of CK Boo
- Short Name:
- J/AJ/143/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precision CCD photometry, a period study, and a two-color simultaneous Wilson code solution of the short-period contact binary CK Bootis. The asymmetric light curves were modeled by a dark spot on the primary component. The result identifies that CK Boo is an A-type W UMa binary with a high fillout of f=71.7(+/-4.4)%. From the O-C curve, it is found that the orbital period changes in a complicated mode, i.e., a long-term increase with two sinusoidal variations. One cyclic oscillation with a period of 10.67(+/-0.20)yr may result from magnetic activity cycles, which are identified by the variability of Max. I-Max. II. Another sinusoidal variation (i.e., A=0.0131days(+/-0.0009days) and P3=24.16(+/-0.64)yr) may be attributed to the light-time effect due to a third body. This kind of additional companion can extract angular momentum from the central binary system. The orbital period secularly increases at a rate of dP/dt=+9.79(+/-0.80)*10^-8days/yr, which may be interpreted by conservative mass transfer from the secondary to the primary. This kind of deep, low-mass ratio overcontact binaries may evolve into a rapid-rotating single star, only if the contact configuration do not break down at J_spin_>(1/3)J_orb_.
