Orbital period changes and possible stellar wind mass loss in the algol-type binary system AT Pegasi

Hanna, Magdy A.

doi:10.1016/j.nrjag.2012.12.003

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…Savedoff (1951) was the first to notice that the orbital period was variable. Although the secular change in the eclipse timing variations has been noted by recent studies (Margrave 1981;Gudur et al 1987;Liakos et al 2012a;Hanna 2012), Liakos et al (2012a) noticed also the discrepancy between the configuration and the direction of the mass transfer. They suggested either mass loss via stellar winds or system angular momentum loss via magnetic braking as possible explanations.…”

Section: At Pegmentioning

confidence: 82%

“…They suggested either mass loss via stellar winds or system angular momentum loss via magnetic braking as possible explanations. Periodic variations in the O-C diagram have been also noted and attributed to unseen third bodies with parameters differing from one study to another (Borkovits & Hegedus 1995, 1996Liakos et al 2012a), or to magnetic activity with single (Sarna et al 1997), or to multiple cycles (Hanna 2012). However there is no firm evidence for strong magnetic activity other than enhanced X-ray emission (Hanna 2012).…”

Section: At Pegmentioning

confidence: 99%

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Photometric, Spectroscopic, and Orbital Period Study of Three Early-Type Semi-Detached Systems: Xz Aql, Ux Her, and at Peg

Zoła

Baştürk

Liakos

et al. 2016

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In this paper we present a combined photometric, spectroscopic and orbital period study of three early-type eclipsing binary systems: XZ Aql, UX Her, and AT Peg. As a result, we have derived the absolute parameters of their components and, on that basis, we discuss their evolutionary states. Furthermore, we compare their parameters with those of other binary systems and with the theoretical models. An analysis of all available up-to-date times of minima indicated that all three systems studied here show cyclic orbital changes; their origin is discussed in detail. Finally, we performed a frequency analysis for possible pulsational behavior and as a result we suggest that XZ Aql hosts a δ Scuti component. published the first light curve solution based on the spectroscopic orbit determined by Sanford (1937) and their own photometric observations. They proposed that the secondary was an evolved, low-mass, late-type star. Hill et al. (1975) estimated the primary component's spectral type as A0V -A3V for different orbital phases. Following the light curve studies of Cester et al. (1979), Mardirossian et al. (1980) and Giuricin & Mardirossian (1981), Lazaro et al. (1997) analyzed the first infrared light curves of the system in J, H and K bands, together with published B and V band light curves of Gordon & Kron (1965). They determined the parameters of the system and found that none of the components of the binary filled their Roche lobes. Although UX Her is a short-period system, they assigned it to a category of slightly detached systems, most of which, as they pointed out, were long-period systems. Djurašević et al. (2006) computed the mass ratio (q = m 2 / m 1 = 0.248) as the result of the q-search method. When combined with the results of their B and V band light curve analysis, this mass ratio value suggests a semi-detached configuration of UX Her. Kurzemnietse (1952) noted for the first time that the period was variable. Tremko et al. (2004) first published a period-variation study of the system, which excluded a mass transfer between the components as the cause of the observed variations in the orbital period of the system, since neither of the stars filled their Roche lobes according to their

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Section: At Pegmentioning

confidence: 82%

Section: At Pegmentioning

confidence: 99%

Photometric, Spectroscopic, and Orbital Period Study of Three Early-Type Semi-Detached Systems: Xz Aql, Ux Her, and at Peg

Zoła

Baştürk

Liakos

et al. 2016

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“…Between these jumps, the period is assumed to have undergone a steady decrease. Similar systems, such as Y Psc, BO Mon, Z Per, and UU And have been studied by Qian [21,22], AT Peg by Hanna [9], BB Peg by Hanna and Awadalla [10]. Using the least squares method, a linear function in each portion is used to obtain the best fit to the (O −C) 2 values:…”

Section: Period Variation Studymentioning

confidence: 99%

Period Variation Study and Light Curve Analysis of the Eclipsing Binary GSC 02013-00288

Awadalla

Hanna

Ismail

et al. 2016

Applied Mathematics and Nonlinear Sciences

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We analyzed the first set of complete CCD light curves of the W UMa type eclipsing binary IK Boo in the BVRI bands by using the PHOEBE code and deduced its first photometric parameters with, mass ratio q = 0.648 and orbital inclination i = 63o. We have applied a spotted model due to the light curves asymmetry. The system shows a distinct O’Connell effect. The best solution fit to the light curves suggested the influence of star spot(s) on both components. Such presence of star spot(s) is common among the RS CVn and W UMa chromospheric active late type stars.We also present an analysis of mid–eclipse time measurements of IK Boo. The analysis indicates a period decrease rate dP/dt = −1.68 × 10−7d/yr, which can be interpreted in terms of mass transfer of rate 3.1 × 10−7M⊙/yr, from the more massive to the less massive component.

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The white dwarf mass–orbital period relation under wind mass-loss

Gao,

2023

Monthly Notices of the Royal Astronomical Society

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Helium white dwarfs (HeWDs) are thought to form from low-mass red giant stars experiencing binary interaction. Because the helium core mass of a red giant star is closely related to the stellar radius, there exists well-known relation between the orbital period (Porb) and the mass (MWD) of the HeWDs, which is almost independent of the type of the companion star. Traditional derivation of the MWD–Porb relation generally neglected the effect of wind mass loss from the red giants, while observations show that wind mass loss from red giants in binary systems is systematically higher than that from isolated stars. In this work, we calculate binary evolution with tidally enhanced stellar wind (TEW) and find that it causes significantly scatter of the traditional MWD–Porb relation. The TEW can prevent the red giants from overflowing their Roche lobes and slow down the growth of the helium core, leaving a lower-mass HeWD for given orbital period. This scenario may account for some of the HeWD binaries that deviate from the traditional MWD–Porb relation. However, we point out that observations of more HeWD binaries in wide orbits are needed to test the TEW model and to constrain the enhanced wind factor.

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Orbital period changes and possible stellar wind mass loss in the algol-type binary system AT Pegasi

Cited by 5 publications

References 28 publications

Photometric, Spectroscopic, and Orbital Period Study of Three Early-Type Semi-Detached Systems: Xz Aql, Ux Her, and at Peg

Photometric, Spectroscopic, and Orbital Period Study of Three Early-Type Semi-Detached Systems: Xz Aql, Ux Her, and at Peg

Period Variation Study and Light Curve Analysis of the Eclipsing Binary GSC 02013-00288

The white dwarf mass–orbital period relation under wind mass-loss

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