Asteroseismology of<i>Kepler</i>Algol-type oscillating eclipsing binaries

Liakos, A.

doi:10.1051/0004-6361/201731247

Cited by 21 publications

(24 citation statements)

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“…As described in previous works (Liakos 2017(Liakos , 2018, the analyses of EBs observed by Kepler LCs require some special attention due to light variations between successive LCs. Therefore, in order to avoid a super simplified model that includes all data points folded into the P orb , the method based on one model per LC (using normal points) or one model per a group of successive LCs folded into the P orb was followed.…”

Section: Light-curve Modelling and Absolute Parameters Calculationmentioning

confidence: 99%

“…The present paper is a continuation of the systematic study on EBs with a δ Scuti component (see also Liakos & Niarchos 2009Liakos & Cagaš 2014;Liakos 2017Liakos , 2018 and aims to enrich the current sample of this kind of systems. For KIC 10686876 only preliminary results have been published regarding its dominant pulsational frequencies (Liakos & Niarchos 2017).…”

Section: Introductionmentioning

confidence: 99%

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Asteroseismology of twoKeplerdetached eclipsing binaries

Liakos

2020

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The present work contains light curve, spectroscopic, and asteroseismic analyses for KIC 04851217 and KIC 10686876. These systems are detached eclipsing binaries hosting a pulsating component of δ Scuti type and have been observed with the unprecedented accuracy of the Kepler space telescope. Using ground-based spectroscopic observations, the spectral types of the primary components of the systems were estimated as A6V and A5V for KIC 04851217 and KIC 10686876, respectively, with an uncertainty of one subclass. The present spectral classification, together with literature radial velocity curves, were used to model the light curves of the systems and, therefore, to calculate the absolute parameters of their components with a higher degree of certainty. The photometric data were analysed using standard eclipsing binary modeling techniques, while their residuals were further analysed using Fourier transformation techniques to extract the pulsation frequencies of their host δ Scuti stars. The oscillation modes of the independent frequencies were identified using theoretical models of δ Scuti stars. The distances of the systems were calculated using the relation between the luminosity and the pulsation period for δ Scuti stars. Here, the physical and the oscillation properties of the pulsating components of these systems are discussed and compared with others of the same type. Moreover, using all the currently known cases of δ Scuti stars in detached binaries, updated correlations between orbital and dominant pulsation periods and between log g and pulsation periods are derived. It can concluded that the proximity of the companion plays significant role in the evolution of the pulsational frequencies.

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Section: Light-curve Modelling and Absolute Parameters Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Asteroseismology of twoKeplerdetached eclipsing binaries

Liakos

2020

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“…Section 1). The method followed for the LC fitting regarding the fixed (filter, albedos A, gravity g, and limb darkening x coefficients) and the adjusted parameters (inclination i, Roche potentials Ω, relative luminosities, temperature of the secondary component) is described in detail in Liakos (2017). The "q-search" method showed very good results for both modes 2 and 5.…”

Section: Light Curve Modelling and Absolute Parameters Calculationmentioning

confidence: 99%

“…Moreover, another useful and recent example regarding the reliability of the "q-search" method concerns the semidetached systems KIC 10581918 and KIC 10619109. Liakos (2017) determined their mass ratio values based only on their Kepler LCs and without any use of RVs. These photometric values of q were later come in very close agreement with the spectroscopically determined ones of Matson et al (2017).…”

Section: Light Curve Modelling and Absolute Parameters Calculationmentioning

confidence: 99%

“…The motivation for this work is based on the rarity of the nature of KIC 8553788. On one hand, only another five oEA systems observed by the Kepler mission have been announced so far (Liakos & Niarchos 2017;Lee et al 2016;Liakos 2017) (the total known are 70) and only three semi-detached systems of R CMa type are known to date (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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KIC 8553788: A pulsating Algol with an extreme mass ratio

Liakos

2018

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Context. The present research paper focuses on the eclipsing binary KIC 8553788 which belongs to two different types of binary systems regarding its physical properties. In particular, it is one of the 71 oscillating stars of Algol type that have been discovered so far and one of the 6 that have been published based on high cadence photometric data of the Kepler mission. In addition, it is one of the four semi-detached binaries of the group of R CMa type systems, while its pulsating component has the fourth fastest frequency among the δ Scuti stars-members of semi-detached binaries. Detailed light curves, spectroscopic and pulsation analyses are presented, while possible explanation scenarios for the evolution of the system involving past mass transfer, mass loss and/or angular momentum loss due to the presence of a tertiary component are discussed.Aims. The goal of the study is to extract the pulsational characteristics of the oscillating star of the system, to estimate the absolute parameters of its components and to provide possible explanation for its extreme evolutionary status. Methods. Ground-based spectroscopic observations using the 2.3 m "Aristarchos" telescope were obtained and used for the estimation of the spectral type of the primary component and to model the light curves of the system with higher certainty. The short cadence photometric data provided by the Kepler mission were analysed using standard eclipsing binary modelling techniques, while Fourier analysis was applied on their residuals aiming to reveal the properties of the intrinsic oscillations. The resulted photometric model was combined with published radial velocity curve to obtain accurate absolute parameters for the components of the system. Results. The results show that the primary component of the system is of A8 spectral type, has a mass of 1.6 M ⊙ , and a radius of 2 R ⊙ . It is a relatively fast pulsator of δ Scuti type that oscillates in 89 frequency modes with the dominant one to be 58.26 cycles day −1 . On the other hand, the secondary component has a mass of only 0.07 M ⊙ , a radius of 1 R ⊙ , and a temperature of 4400 K. In addition, it was found to be magnetically active with migrating cool spots on its surface. Conclusions. KIC 8553788 according to its geometrical configuration and its pulsational properties belongs to the group of the oscillating stars of Algol type, while according to its very low mass ratio and its relatively short orbital period belongs also to the group of R CMa stars. If confirmed by radial velocity data of the secondary component, the system would have the lowest mass ratio that has ever been found in semi-detached systems and it can be considered as one of the most extreme cases.

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Systematic search for stellar pulsators in the eclipsing binaries observed byKepler

Gaulme

Guzik

2019

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Eclipsing binaries (EBs) are unique targets for measuring precise stellar properties and constrain stellar evolution models. In particular, it is possible to measure at the percent level masses and radii of both components of a double-lined spectroscopic EB. Since the advent of high-precision photometric space missions (MOST, CoRoT, Kepler, BRITE, TESS), the use of stellar pulsation properties to infer stellar interiors and dynamics constitutes a revolution for low-mass star studies. The Kepler mission has led to the discovery of thousands of classical pulsators such as δ Scuti and solar-like oscillators (main sequence and evolved), but also almost 3000 EBs with orbital periods shorter than 1100 days. We report the first systematic search for stellar pulsators in the entire Kepler eclipsing binary catalog. The focus is mainly aimed at discovering δ Scuti, γ Doradus, red giant, and tidally excited pulsators. We developed a data inspection tool (DIT) that automatically produces a series of plots from the Kepler light-curves that allows us to visually identify whether stellar oscillations are present in a given time series. We applied the DIT to the whole Kepler eclipsing binary database and identified 303 systems whose light curves display oscillations, including 163 new discoveries. A total of 149 stars are flagged as δ Scuti (100 from this paper), 115 stars as γ Doradus (69 new), 85 stars as red giants (27 new), 59 as tidally excited oscillators (29 new). There is some overlap among these groups, as some display several types of oscillations. Despite many of these systems are likely to be false positives, i. e., when an EB light curve is blended with a pulsator, this catalog gathers a vast sample of systems that are valuable for a better understanding of stellar evolution.

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Asteroseismology ofKeplerAlgol-type oscillating eclipsing binaries

Cited by 21 publications

References 54 publications

Asteroseismology of twoKeplerdetached eclipsing binaries

Asteroseismology of twoKeplerdetached eclipsing binaries

KIC 8553788: A pulsating Algol with an extreme mass ratio

Systematic search for stellar pulsators in the eclipsing binaries observed byKepler

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