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Paper: A Spectroscopic and Photometric Study of the Interacting Binary and Double Period Variable HD 170582
Volume: 496, Living Together: Planets, Host Stars and Binaries
Page: 175
Authors: Mennickent, R. E.; Djurasevic, G.; Cabezas, M.; Cséki, A.; Rosales, J.; Niemczura, E.; Araya, I.; Curé, M.
Abstract: We present a spectroscopic and photometric study of the interacting binary and double-period variable HD 170582. Based on the study of the ASAS V-band light curve we have determined an improved orbital period of 16.87177±0.021 days and a long period of 587 days. We disentangled the light curve into an orbital part, determining ephemerides and revealing orbital ellipsoidal variability with unequal maxima, and a long cycle, showing quasi-sinusoidal changes with V-band amplitude 0.1 mag. From the analysis of 136 CHIRON/CTIO high-resolution optical spectra, the model of the V-band ASAS light curve and the fit of the spectral energy distribution, we determined the physical parameters for the stars and the circumprimary disk, the distance to the system and general system dimensions, the reddening, and the metallicity. The disk contributes about 35% to the system luminosity in the V-band. Two extended regions located at opposite sides of the disk rim, and hotter than the disk by 67% and 46%, fit the light curve asymmetries. These structures can be attributed to shocks produced by disk gas dynamics and gas stream interaction. The system is seen under an inclination of 67°, and is at a distance of 238 pc. We discuss the double-line nature of He I 5875; two absorption components move in anti-phase during the orbital cycle. One of these components probably arises from a wind in the stream/disk interaction region, near the hot spot. We find that HD 170582 is one of the systems showing a discrepancy between the color excess obtained from diffuse interstellar bands and that obtained from the analysis of the spectral energy distribution. This might be attributed to the influence of circumstellar matter. This study of HD 170582 will help to understand the class of interacting binaries dubbed ‘Double Periodic Variables'.
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