EDP Sciences
Free access
Volume 398, Number 3, February II 2003
Page(s) 1091 - 1102
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20021688

A&A 398, 1091-1102 (2003)
DOI: 10.1051/0004-6361:20021688

On the detectability of long period perturbations in close hierarchical triple stellar systems

T. Borkovits1, B. Érdi2, E. Forgács-Dajka2 and T. Kovács2

1  Baja Astronomical Observatory of Bács-Kiskun County, PO Box 766, 6500 Baja, Szegedi út, Hungary
2  Department of Astronomy, Eötvös Loránd University, 1117 Budapest, Pázmány P. sétány 1/A, Hungary
    e-mail: B.Erdi@astro.elte.hu; E.Forgacs-Dajka@astro.elte.hu; ktomo@freemail.hu

(Received 26 September 2002 / Accepted 12 November 2002 )

We study the possibility of the detection of the low amplitude long ( P') period perturbative effect of a distant third companion on the motion of a close binary. We give a new, more accurate analytical formula for this kind of perturbation affecting the moments of the times of minima in eclipsing binaries. The accuracy of this formula is tested by numerical integrations carried out for several initial configurations. We also describe a numerical method based on a non-linear Levenberg-Marquardt algorithm which makes it possible to separate this dynamical effect from the pure geometrical light-time effect in the eclipsing O-C diagram. The capabilities of this new method are demonstrated by the analysis of numerically simulated O-Cs for test systems having physical parameters very similar to Algol and IU Aur . The results show that the above mentioned effect would be detectable in these systems nowadays, observing almost each minima events in a 1- 2 year-long interval.

Key words: methods: analytical -- methods: numerical -- celestial mechanics -- binaries: close -- binaries: eclipsing

Offprint request: T. Borkovits, borko@electra.bajaobs.hu

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