We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an acc...We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an accreting magnetic white dwarf.The hydrogen emission lines exhibit a narrow component formed on the irradiated hemisphere of the donor.The Doppler tomography revealed differences in the positions of emission regions of hydrogen and HeⅡλ4686 lines.The spectra exhibit a Zeeman absorption triplet of the Hαline,formed in the cold halo around the accretion spot at a magnetic field strength of B=15.1±1.3 MG.The spectra of the bright phase have a red cyclotron continuum,whose orbital variability has been interpreted within a simple model of an accretion spot.The modeling of the cyclotron continuum constrains the white dwarf's magnetic field to B_(cyc)■45 MG.The analysis of the eclipse light curve and the radial velocities of the irradiated hemisphere yielded estimates for the orbital inclination■,the mass ratio 0.23≤q≤0.43,and the white dwarf mass 0.72≥M_(1)/M_(⊙)≥0.42.展开更多
In this study,the apsidal motion analyses of the eclipsing binary systems V398 Lac,V2544 Cyg,and V785 Cas are presented.The(O-C)diagrams of the selected systems were constructed using all available and reliable times ...In this study,the apsidal motion analyses of the eclipsing binary systems V398 Lac,V2544 Cyg,and V785 Cas are presented.The(O-C)diagrams of the selected systems were constructed using all available and reliable times of minimum light compiled from the literature.As a result,the apsidal motion periods were determined to be 353±50 yr,43.3±5.1 yr and 83.4±8.5 yr,respectively.Furthermore,the TESS light curves of the three systems were analyzed to derive their photometric and absolute parameters.The component masses were determined as follows:for V398 Lac,M_(1)=3.83±0.35 M_(⊙)and M2=3.27±0.35 M_(⊙);for V2544 Cyg,M_(1)=1.75±0.38 M_(⊙)and M2=1.40±0.38 M_(⊙);for V785 Cas,M_(1)=5.64±0.41 M_(⊙)and M2=5.18±0.41 M_(⊙).The parameters related to apsidal motion,as well as the observational and theoretical internal structure constants(K_(2,obs) and K_(2,teo))were calculated for studied binaries.The relativistic contribution to the observed apsidal motion rate was found to be relatively small,constituting less than approximately 5%of the total rate in each system.The theoretical internal structure constants were derived from the evolutionary models,assuming a standard chemical composition of(X,Z)=(0.70,0.01).展开更多
Despite many attempts,the origin of UV emission line and continuum in contact binary stars remains unclear.We present a substantial UV spectroscopic analysis of VW Cephei,a late-type contact binary system,using 46 low...Despite many attempts,the origin of UV emission line and continuum in contact binary stars remains unclear.We present a substantial UV spectroscopic analysis of VW Cephei,a late-type contact binary system,using 46 lowresolution spectra from the International Ultraviolet Explorer in the wavelength range 1150-1978À.By modeling continuum and emissions lines in individual spectra,we report the significant detection of O Ⅲ](1660 and 1666À)and Si Ⅳ(1393 and 1402À)line complexes.We observe that UV fluxes for both continuum and emission lines like C Ⅳ,O Ⅲ],C Ⅱ and Si Ⅳ vary significantly(fractional rms variability up to 45%)from hours to years.In addition,line widths also change by hundreds of km s^(-1).The UV flux variabilities observed in the continuum bands and line emissions are uncorrelated.However,most of the flux values follow the binary orbital period observed from optical data.Our analysis indicates that,while the variation in continuum flux may be attributed to a heated photosphere,the line width measurements indicate that the emission lines are likely formed in the dynamical clouds associated with Roche lobe overflow.We estimate the mass transfer rate of M=(0.82±0.01)×10^(-7)M_(⊙)yr^(-1)from UV line fluxes,which is in good agreement with optical studies.展开更多
Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spe...Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spectral energy distribution of the system.The method results in the effective temperatures at 7100±50 K for component A and 7000±50 K for component B,while their masses measure as 1.65±0.15M_(⊙)for component A and1.58±0.14M_(⊙)for component B.The system exists at an estimated age of 0.794 Gyr,while both stars remain in their initial subgiant evolutionary phase.The evolutionary tracks together with isochrones for Z=0.03 validate that the system components share both their origin and chemical compositions.The orbital analysis shows that the system has a period of 15.97 yr and an eccentricity of 0.713,while the total system mass amounts to3.65±0.49 M_(⊙).We detailedly analyze the system's orbital dynamics to assess planetary stability and habitability zones,which lead to the dynamics of circumbinary(P-type)and circumstellar(S-type)orbits using empirical criteria,revealing large regions in which planetary orbits remain dynamically stable.Luminosities and effective temperatures of each stellar component are used to determine their habitable zones.展开更多
基金supported by the Ministry of Science and Higher Education of the Russian Federation。
文摘We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an accreting magnetic white dwarf.The hydrogen emission lines exhibit a narrow component formed on the irradiated hemisphere of the donor.The Doppler tomography revealed differences in the positions of emission regions of hydrogen and HeⅡλ4686 lines.The spectra exhibit a Zeeman absorption triplet of the Hαline,formed in the cold halo around the accretion spot at a magnetic field strength of B=15.1±1.3 MG.The spectra of the bright phase have a red cyclotron continuum,whose orbital variability has been interpreted within a simple model of an accretion spot.The modeling of the cyclotron continuum constrains the white dwarf's magnetic field to B_(cyc)■45 MG.The analysis of the eclipse light curve and the radial velocities of the irradiated hemisphere yielded estimates for the orbital inclination■,the mass ratio 0.23≤q≤0.43,and the white dwarf mass 0.72≥M_(1)/M_(⊙)≥0.42.
基金Funding for TESS is provided by the NASA Science Mission Directorate。
文摘In this study,the apsidal motion analyses of the eclipsing binary systems V398 Lac,V2544 Cyg,and V785 Cas are presented.The(O-C)diagrams of the selected systems were constructed using all available and reliable times of minimum light compiled from the literature.As a result,the apsidal motion periods were determined to be 353±50 yr,43.3±5.1 yr and 83.4±8.5 yr,respectively.Furthermore,the TESS light curves of the three systems were analyzed to derive their photometric and absolute parameters.The component masses were determined as follows:for V398 Lac,M_(1)=3.83±0.35 M_(⊙)and M2=3.27±0.35 M_(⊙);for V2544 Cyg,M_(1)=1.75±0.38 M_(⊙)and M2=1.40±0.38 M_(⊙);for V785 Cas,M_(1)=5.64±0.41 M_(⊙)and M2=5.18±0.41 M_(⊙).The parameters related to apsidal motion,as well as the observational and theoretical internal structure constants(K_(2,obs) and K_(2,teo))were calculated for studied binaries.The relativistic contribution to the observed apsidal motion rate was found to be relatively small,constituting less than approximately 5%of the total rate in each system.The theoretical internal structure constants were derived from the evolutionary models,assuming a standard chemical composition of(X,Z)=(0.70,0.01).
基金DST,Government of India for the award of INSPIRE fellowship(IF230384)。
文摘Despite many attempts,the origin of UV emission line and continuum in contact binary stars remains unclear.We present a substantial UV spectroscopic analysis of VW Cephei,a late-type contact binary system,using 46 lowresolution spectra from the International Ultraviolet Explorer in the wavelength range 1150-1978À.By modeling continuum and emissions lines in individual spectra,we report the significant detection of O Ⅲ](1660 and 1666À)and Si Ⅳ(1393 and 1402À)line complexes.We observe that UV fluxes for both continuum and emission lines like C Ⅳ,O Ⅲ],C Ⅱ and Si Ⅳ vary significantly(fractional rms variability up to 45%)from hours to years.In addition,line widths also change by hundreds of km s^(-1).The UV flux variabilities observed in the continuum bands and line emissions are uncorrelated.However,most of the flux values follow the binary orbital period observed from optical data.Our analysis indicates that,while the variation in continuum flux may be attributed to a heated photosphere,the line width measurements indicate that the emission lines are likely formed in the dynamical clouds associated with Roche lobe overflow.We estimate the mass transfer rate of M=(0.82±0.01)×10^(-7)M_(⊙)yr^(-1)from UV line fluxes,which is in good agreement with optical studies.
文摘Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spectral energy distribution of the system.The method results in the effective temperatures at 7100±50 K for component A and 7000±50 K for component B,while their masses measure as 1.65±0.15M_(⊙)for component A and1.58±0.14M_(⊙)for component B.The system exists at an estimated age of 0.794 Gyr,while both stars remain in their initial subgiant evolutionary phase.The evolutionary tracks together with isochrones for Z=0.03 validate that the system components share both their origin and chemical compositions.The orbital analysis shows that the system has a period of 15.97 yr and an eccentricity of 0.713,while the total system mass amounts to3.65±0.49 M_(⊙).We detailedly analyze the system's orbital dynamics to assess planetary stability and habitability zones,which lead to the dynamics of circumbinary(P-type)and circumstellar(S-type)orbits using empirical criteria,revealing large regions in which planetary orbits remain dynamically stable.Luminosities and effective temperatures of each stellar component are used to determine their habitable zones.
