HD183648: a Kepler eclipsing binary with anomalous ellipsoidal variations and a pulsating component
| Autor: | B. Csák, Róbert Szabó, D. W. Kurtz, John Southworth, J. Sztakovics, Aliz Derekas, Krešimir Pavlovski, József Kovács, Á. Dózsa, Tamás Borkovits, F. Maloney, I. B. Biro, Jim Fuller, Andrej Prsa, Gy. M. Szabó, Kelly Hambleton, V. Kolbas, Karen Kinemuchi, I. Jankovics |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
QC1-999
FOS: Physical sciences Binary number Astrophysics F500 01 natural sciences Photometry (optics) 0103 physical sciences 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) QC QB Physics 010308 nuclear & particles physics Apsidal precession Astronomy Astronomy and Astrophysics Light curve Orbital period Radial velocity Amplitude Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science binary stars eclipsing binary stars stars stellar oscillations Main sequence |
| Zdroj: | EPJ Web of Conferences, Vol 101, p 06021 (2015) |
| ISSN: | 2100-014X 1365-2966 0035-8711 |
| Popis: | KIC 8560861 (HD 183648) is a marginally eccentric (e=0.05) eclipsing binary with an orbital period of P_orb=31.973d, exhibiting mmag amplitude pulsations on time scales of a few days. We present the results of the complex analysis of high and medium-resolution spectroscopic data and Kepler Q0 -- Q16 long cadence photometry. The iterative combination of spectral disentangling, atmospheric analysis, radial velocity and eclipse timing variation studies, separation of pulsational features of the light curve, and binary light curve analysis led to the accurate determination of the fundamental stellar parameters. We found that the binary is composed of two main sequence stars with an age of 0.9\+-0.2 Gyr, having masses, radii and temperatures of M_1=1.93+-0.12 M_sun, R_1=3.30+-0.07 R_sun, T_eff1=7650+-100 K for the primary, and M_2=1.06+-0.08 M_sun, R_2=1.11+-0.03 R_sun, T_eff2=6450+-100 K for the secondary. After subtracting the binary model, we found three independent frequencies, two of which are separated by twice the orbital frequency. We also found an enigmatic half orbital period sinusoidal variation that we attribute to an anomalous ellipsoidal effect. Both of these observations indicate that tidal effects are strongly influencing the luminosity variations of HD 183648. The analysis of the eclipse timing variations revealed both a parabolic trend, and apsidal motion with a period of (P_apse)_obs=10,400+-3,000 y, which is three times faster than what is theoretically expected. These findings might indicate the presence of a distant, unseen companion. 16 pages, 12 figures; accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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