Apsidal motion in the close binary IT cassiopeiae

Kozyreva, V. S.; Zakharov, A. I.

doi:10.1134/1.1415860

Cited by 16 publications

(14 citation statements)

References 7 publications

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“…5 and 6 and is denoted by a star. However, we did not consider this system in our present investigation since there seems to be a discrepancy in its observed apsidal-motion rate (Lacy et al 1997;Kozyreva & Zakharov 2001). …”

Section: Comparison With Observationsmentioning

confidence: 99%

New results on the apsidal-motion test to stellar structure and evolution including the effects of dynamic tides

Claret

Willems²

2002

A&A

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Abstract. We revised the current status of the apsidal-motion test to stellar structure and evolution. The observational sample was increased by about 50% in comparison to previous studies. Classical and relativistic systems were analyzed simultaneously and only systems with accurate absolute dimensions were considered. New interior models incorporating recent opacity tables, stellar rotation, mass loss, and moderate core overshooting were used as theoretical tools to compare the predicted with the observed shifts of the position of the periastron. The stellar models were computed for the precise observed masses and the adopted chemical compositions are consistent with the corresponding tables of opacities to avoid the inherent problems of interpolation in mass and in (X, Z). The derived chemical composition for each individual system was used to infer the primordial helium content as well as a law of enrichment. The values found are in good agreement with those obtained from various independent sources. For the first time, the effects of dynamic tides are taken into account systematically to determine the contribution of the tidal distortion to the predicted apsidal-motion rate. The deviations between the apsidal-motion rates resulting from the classical formula and those determined by taking into account the effects of dynamic tides are presented as a function of the level of synchronism. For systems close to synchronisation, dynamic tides cause deviations with respect to the classical apsidal-motion formula due to the effects of the compressibility of the stellar fluid. For systems with higher rotational angular velocities, additional deviations due to resonances arise when the forcing frequencies of the dynamic tides come into the range of the free oscillation modes of the component stars. The resulting comparison shows a good agreement between the observed and theoretical apsidal-motion rates. No systematic effects in the sense that models are less mass concentrated than real stars and no correlations with the evolutionary status of the systems were detected.

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Section: Comparison With Observationsmentioning

confidence: 99%

New results on the apsidal-motion test to stellar structure and evolution including the effects of dynamic tides

Claret

Willems²

2002

A&A

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“…They also excluded the previous reports of δ Scuti variations. Kozyreva & Zakharov (2001) obtained WBVR photoelectric measurements and determined the longer apsidal-motion period of U = 3300±750 years.…”

Section: It Casmentioning

confidence: 99%

Relativistic apsidal motion in eccentric eclipsing binaries

Wolf¹,

Claret²,

Kotková

et al. 2010

A&A

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Context. The study of apsidal motion in detached eclipsing binary systems is known to be an important source of information about stellar internal structure as well as the possibility of verifying of General Relativity outside the Solar System. Aims. As part of the long-term Ondřejov and Ostrava observational projects, we aim to measure precise times of minima for eccentric eclipsing binaries, needed for the accurate determination of apsidal motion, providing a suitable test of the effects of General Relativity. Methods. About seventy new times of minimum light recorded with photoelectric or CCD photometers were obtained for ten eccentric-orbit eclipsing binaries with significant relativistic apsidal motion. Their O-C diagrams were analysed using all reliable timings found in the literature, and new or improved elements of apsidal motion were obtained. Results. We confirm very long periods of apsidal motion for all systems. For BF Dra and V1094 Tau, we present the first apsidalmotion solution. The relativistic effects are dominant, representing up to 100% of the total observable apsidal-motion rate in several systems. The theoretical and observed values of the internal structure constant k 2 were compared for systems with lower relativistic contribution. Using the light-time effect solution, we predict a faint third component for V1094 Tau orbiting with a short period of about 8 years.

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“…To test the tidal contribution from KOI-126 A on B and C we simulate a binary system containing a star identical to KOI-126 A and another with the same mass as KOI-126 B and C combined and radius equal to their semi-major axis. A value for k 2 was approximated using a star of similar mass for which k 2 has been observationally measured (IT Cas: M = 1.3315M , k 2 = 0.0038 (Kozyreva & Zakharov 2001)), while 0 was used for the B and C stand-in. The resulting binary has a total tidal and rotational precession rate of ω = 6.8 × 10 −11 deg/cycles, while the GR contribution is ω = 8.6 × 10 −5 .…”

Section: Methodsmentioning

confidence: 99%

Photodynamical Modeling of the Fascinating Eclipses in the Triple-Star System KOI-126

Yenawine,

Welsh,

Orosz

et al. 2021

Preprint

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We explore the fascinating eclipses and dynamics of the compact hierarchical triple star system . This system is comprised of a pair of M-dwarf stars (KOI-126 B and C) in a 1.74 day orbit which revolve around an F-star (KOI-126 A) every 34 days. Complex eclipse shapes are created as the M stars transit the F star, due to two effects: (i) the duration of the eclipse is a significant fraction of the M-star orbital period, so the prograde or retrograde motion of the M stars in their orbit lead to unusually short or long duration eclipses; (ii) due to 3-body dynamics, the M-star orbit precesses with an astonishingly quick timescale of 1.74 years for the periastron (apsidal) precession, and 2.73 years for the inclination and nodal angle precession. Using the full Kepler data set, supplemented with ground-based photometry, plus 29 radial velocity measurements that span 6 years, our photodynamical modeling yields masses of M A = 1.2713 ± 0.0047 M (0.37%), M B = 0.23529 ± 0.00062 M (0.26%), and M C = 0.20739 ± 0.00055 M (0.27%) and radii of R A = 1.9984 ± 0.0027 R (0.14%), R B = 0.25504 ± 0.00076 R (0.3%), and R C = 0.23196 ± 0.00069 R (0.3%). We also estimate the apsidal motion constant of the M-dwarfs, a parameter that characterizes the internal mass distribution. While not particularly precise, we measure a mean apsidal motion constant, k 2 , of 0.046 +0.046 −0.028 , which is approximately 2-σ lower than the theoretical model prediction of 0.150. We explore possible causes for this discrepancy.

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Apsidal motion in the close binary IT cassiopeiae

Cited by 16 publications

References 7 publications

New results on the apsidal-motion test to stellar structure and evolution including the effects of dynamic tides

New results on the apsidal-motion test to stellar structure and evolution including the effects of dynamic tides

Relativistic apsidal motion in eccentric eclipsing binaries

Photodynamical Modeling of the Fascinating Eclipses in the Triple-Star System KOI-126

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