Physical parameters of components in close binary systems. I

Kreiner, J. M.; Ruciński, S. M.; Zoła, S.; Niarchos, P. G.; Ogłoza, W.; Stachowski, G.; Baran, A.; Gazeas, K.; Dróżdż, M.; Zakrzewski, B.; Pokrzywka, B.; Kjurkchieva, D.; Marchev, D.

doi:10.1051/0004-6361:20031456

Cited by 52 publications

(30 citation statements)

References 24 publications

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“…The evolution theories of these binary stars yield secular as well as shorter time scale quasi-cyclical orbital period variations. Although these theories suffer from a lot of problems their predictions can be used as guidelines (Kreiner et al 2003;Kähler 2004) to better understand the behaviour of these systems.…”

Section: Long-term Effectsmentioning

confidence: 99%

Indirect evidence for short period magnetic cycles in W UMa stars

Borkovits¹,

Elkhateeb

Csizmadia

et al. 2005

A&A

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Complex period variations of five W UMa type binaries (AB And, OO Aql, DK Cyg, V566 Oph, U Peg) were investigated by analyzing their O−C diagrams, and several common features were found. Four of the five systems show secular period variations at a constant rate on the order of |Ṗ sec /P| ∼ 10 −7 yr −1 . In the case of AB And, OO Aql, and U Peg a high-amplitude, nearly one-century long quasi-sinusoidal pattern was also found. It might be explained as light-time effect, or by some magnetic phenomena, although the mathematical, and consequently the physical, parameters of these fits are very problematic, as the obtained periods are very close to the length of the total data range. The most interesting feature of the studied O−C diagrams is a low amplitude (∼2−4 × 10 −3 d) modulation with a period around 18-20 yr in four of the five cases. This phenomenon might be indirect evidence of some magnetic cycle in late-type overcontact binaries as an analog to the observed activity cycles in RS CVn systems.

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Section: Long-term Effectsmentioning

confidence: 99%

Indirect evidence for short period magnetic cycles in W UMa stars

Borkovits¹,

Elkhateeb

Csizmadia

et al. 2005

A&A

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“…Times of minima of contact binaries presented in this work are by-product of the W UMa Project (Papers I -VII) (Kreiner et al 2003;Baran et al 2004;Zola et al 2004;Gazeas et al 2005;Zola et al 2005;Gazeas et al 2006;Zola et al 2010. ), which aims in performing accurate photometric and spectroscopic study of eclipsing binaries of W UMa type.…”

Section: Acknowledgementsmentioning

confidence: 82%

120 Minima timings of eclipsing binaries

Palafouta¹,

Gazeas²,

Christopoulou³

et al. 2017

IBVS

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“…In total, 41 systems were observed with the results from light curve modelling available in the series of papers: Kreiner et al (2003), Baran et al (2004), Zola et al (2004), Gazeas, Baran et al (2005), Zola et al (2005), Gazeas, Niarchos et al (2005). In all cases, the light curve modelling was performed using the Wilson-Devinney code (Wilson, 1979(Wilson, , 1993 supplemented by a Monte Carlo search method.…”

Section: Aims Of the Programmentioning

confidence: 99%

The W UMa-type Stars Program: First Results, Current Status and Perspectives

Kreiner

Zoła

Ogłoza

et al. 2006

Astrophys Space Sci

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We present the results of a statistical investigation of the period-color and period-bolometric magnitude relations using a carefully selected sample of 120 contact systems with known physical parameters.Keywords Eclipsing binaries . W UMa stars . Physical parameters Aims of the programThe primary aim of this program is the discussion of certain relations between the most important parameters of contact binary systems. Our approach is novel in that the absolute parameters (masses, radii and luminosities) of the systems have been derived for a homogeneous sample obtained by observation according to the following criteria: 1) The star has a mass ratio q sp determined spectroscopically. 2) The complete light curve for a given system is obtained at one observatory using the same telescope and the same instrument (a CCD camera or a multichannel photoelectric photometer) with an accuracy of at least ±0.01 mag.3) The light curves are obtained in the shortest possible time to avoid any possible changes in the light curve due to, for example, spot activity. In total, 41 systems were observed with the results from light curve modelling available in the series of papers: . In all cases, the light curve modelling was performed using the Wilson-Devinney code (Wilson, 1979(Wilson, , 1993 supplemented by a Monte Carlo search method. The effective temperature was derived from the spectral type, while the mass ratio q was deduced from spectroscopic measurements. The separation a and fill-out factor f were obtained as a result, allowing calculation of the effective surface S(q, f )a 2 of the binary (see Mochnacki, 1984). The above quantities, together with the temperature difference between the components, was used to compute the bolometric absolute magnitude M bol of the system. The mean color index (B −V ), bolometric correction BC and absolute visible magnitude M V were derived assuming that the radiative properties of the common envelope can be described using formulae adequate for main sequence stars (e.g. Popper, 1980). The sample of 41 contact systems obtained in this way was augmented using data from the literature. Only parameters derived from models with spectroscopically-determined mass ratios were taken into account. Relations between some parametersW UMa stars are interesting objects as distance tracers. Extensive work concerning the M V (log P, B −V ) calibration has been done in the series of papers by Rucinski and co-workers e.g. Rucinski (2000) or Rucinski and Duerbeck Springer

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Physical parameters of components in close binary systems. I

Cited by 52 publications

References 24 publications

Indirect evidence for short period magnetic cycles in W UMa stars

Indirect evidence for short period magnetic cycles in W UMa stars

120 Minima timings of eclipsing binaries

The W UMa-type Stars Program: First Results, Current Status and Perspectives

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