The chromospherically active binary CF Tuc revisited
In: Monthly notices of the Royal Astronomical Society (Print), Jg. 397 (2009), Heft 3, S. 1647-1660
Online
academicJournal
- print, 3/4 p
Zugriff:
This paper presents results derived from analysis of new spectroscopic and photometric observations of the chromospherically active binary system CFTuc. New high-resolution spectra, taken at the Mt. John University Observatory in 2007, were analysed using two methods: cross-correlation and Fourier-based disentangling. As a result, new radial velocity curves of both components were obtained. The resulting orbital elements of CF Tuc are a 1 sin i = 0.0254 ± 0.0001 au, a2 sin i = 0.0228 ± 0.0001 au, M1 sin i = 0.902 ± 0.005 M⊙ and M2 sin i = 1.008 ± 0.006 M⊙. The cooler component of the system shows Hα and Ca II H&K emissions. Using simultaneous spectroscopic and photometric observations, an anticorrelation between the Hα emission and the BV light curve maculation effects was found. This behaviour indicates a close spatial association between photospheric and chromospheric active regions. Our spectroscopic data and recent BV light curves were solved simultaneously using the Wilson-Devinney code. A dark spot on the surface of the cooler component was assumed to explain large asymmetries observed in the light curves. The following absolute parameters of the components were determined: M1 = 1.11 ± 0.01 M⊙, M2 = 1.23 ± 0.01 M⊙, R1 = 1.63 ± 0.02 R⊙, R2= 3.60 ± 0.02 R⊙, L1 = 3.32 ± 0.51 L⊙ and L2 = 3.91 ± 0.84 L⊙. The primary component has an age of about 5 Gyr and is approaching its main-sequence terminal age. The distance to CF Tuc was calculated to be 89 ± 6 pc from the dynamic parallax, neglecting interstellar absorption, in agreement with the Hipparcos value. The orbital period of the system was studied using the O-C analysis. The O-C diagram could be interpreted in terms of either two abrupt changes or a quasi-sinusoidal form superimposed on a downward parabola. These variations are discussed by reference to the combined effect of mass transfer and mass loss, the Applegate mechanism and also a light-time effect due to the existence of a third body in the system.
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The chromospherically active binary CF Tuc revisited
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Autor/in / Beteiligte Person: | DOGRU, D ; ERDEM, A ; DOGRU, S. S ; ZOLA, S |
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Zeitschrift: | Monthly notices of the Royal Astronomical Society (Print), Jg. 397 (2009), Heft 3, S. 1647-1660 |
Veröffentlichung: | Malden, MA: Wiley-Blackwell, 2009 |
Medientyp: | academicJournal |
Umfang: | print, 3/4 p |
ISSN: | 0035-8711 (print) |
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