The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O'Connell effect caused by spot/facula modulation.The radial velocity(RV)measurements are derived by using the tomographic spectra disentangling technology.The mass ratio q=K1/K2=0.812±0.007,and the orbital semimajor axis a sin i=14.984±0.048 R☉ are obtained by fitting the RV curves.We optimize the binary model concerning the spot/facula activity with the code PHOEBE and obtain precise parameters of the orbit including the eccentricity e=0.0217±0.0008,the inclination i=87°.71±0°.04,and the angle of periastron ω=284°.1±0°.5.The masses and radii of the primary and secondary star are determined as M1=1.3467±0.0001 M☉,R1=1.569±0.003 R☉,and M2=1.0940±0.0001 M☉,R2=1.078±0.002 R☉,respectively.The ratio of temperatures of the two component stars is rteff=0.924±0.001.We also obtain the periastron precession speed of 0.000024±0.000001 day cycle-1.The residuals of out-of-eclipse are analyzed using the auto-correlation function and the discrete Fourier transform.The spot/facula activity is relatively weaker,but the lifetime is longer than that of most single main sequence stars in the same temperature range.The average rotation period of the spots Prot=4.32 days is slightly longer than the orbital period,which may be caused by either the migration of spots/faculae along the longitude or the latitudinal differential rotation.The activity may be spot-dominated for the secondary star and facula-dominated for the primary star.The method of this work can be used to analyze more eclipsing binaries with the O'Connell effect in the Kepler field to obtain the precise parameters and investigate the difference of spot behavior between binaries and single stars.It is helpful for a deeper understanding of the stellar magnetic activity and dynamo theory.

Hu-Biao Niu;Jian-Ning Fu;Jia-Xin Wang;Chun-Qian Li

Department of Astronomy,Beijing Normal University,Beijing 100875,China;Xinjiang Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011,China;Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China

天文和天体物理学研究

[1]Hu-Biao Niu;Jian-Ning Fu;Jia-Xin Wang;Chun-Qian Li-.Spot and Facula Activity Variations of the Eccentric Detached Eclipsing Binary KIC 8098300 Based on the Time-series Orbital Solutions)[J].天文和天体物理学研究,2022(01):174-188

Facula,Eclipsing,eclipsing,facula,semimajor,PHOEBE,periastron,rteff,faculae,binaries

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