Photometric Study of Two Totally Eclipsing Contact Binaries: V789 Her and V1007 Cas

Li, K.; Xia, Qi-Qi; Hu, Shijian; Guo, Dadong; Chen, X.

doi:10.1088/1538-3873/aac067

Cited by 29 publications

(7 citation statements)

References 46 publications

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“…A cool spot on the star 1 can explain the asymmetric light maxima, well-known as the O'Connell effect. This effect was also similarly found to be evidence of star-spot activities of one component or both components in many W-type contact systems such as V789 Her (Li et al 2018), V474 Cam (Guo et al 2018), RW Dor (Sarotsakulchai et al 2019) and TY UMa (Li et al 2015). The fitted light curves are shown in Figure 3.…”

Section: Light Curve Fitsupporting

confidence: 58%

Photometric analysis and evolutionary stages of the contact binary V2790 Ori

Kriwattanawong

2019

Res. Astron. Astrophys.

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A photometric analysis and evolutionary stages of the contact binary V2790 Ori is presented. The BV R C observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to use in the analysis of evolutionary stages of the binary. The results show that V2790 Ori is a W-type contact system with a mass ratio of q = 2.932. The orbital period increase is found at a rate of dP/dt = 1.03×10 −7 d yr −1 . It implies that a rate of mass transfer from the secondary component to the primary one is dm 2 /dt = 6.31×10 −8 M ⊙ yr −1 . Furthermore, we find that from the detached phase to the contact phase, mass of the evolved secondary component has been lost 1.188±0.110 M ⊙ , i.e., mass lost by the system of 0.789±0.073 M ⊙ and mass transfer to the primary of 0.399±0.037 M ⊙ . Since the time of the first overflow, the angular momentum loss is found to be 72.2 % of J FOF , causing the orbit and Roche surface to shrink until the present time.

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Section: Light Curve Fitsupporting

confidence: 58%

Photometric analysis and evolutionary stages of the contact binary V2790 Ori

Kriwattanawong

2019

Res. Astron. Astrophys.

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“…The study of orbital period variation is of great significance for discussing the dynamic interaction of the binary systems, the existence of a third body and the materials transfer between the two components of binary systems (Zhou et al 2016;Er-gang et al 2019;Li et al 2018;Liao et al 2019;Pi et al 2019). Therefore, the research of the orbital period variation has always been an important part of the binary systems.…”

Section: Orbital Period Investigationsmentioning

confidence: 99%

The study of eleven contact binaries with mass ratios less than 0.1

Liu¹,

Li²,

Michel³

et al. 2023

Preprint

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Multi-band photometric observations of eleven totally eclipsing contact binaries were carried out. Applying the Wilson-Devinney program, photometric solutions were obtained. There are two W-subtype systems, which are CRTS J133031.1+161202 and CRTS J154254.0+324652, and the rest systems are A-subtype systems. CRTS J154254.0+324652 has the highest fill-out factor with 94.3%, and the lowest object is CRTS J155009.2+493639 with only 18.9%. The mass ratios of the eleven systems are all less than 0.1, which means that they are extremely low mass ratio binary systems. We performed period variation investigation and found that the orbital periods of three systems decrease slowly, which may be caused by the angular momentum loss, and of six systems increase slowly, which indicates that the materials may transfer from the secondary component to the primary component. LAMOST low−resolution spectra of four objects were analyzed, and using the spectral subtraction technique, H𝛼 emission line was detected, which means that the four objects exhibit chromospheric activity. In order to understand their evolutionary status, the mass-luminosity and mass-radius diagrams were plotted. The two diagrams indicate that the primary component is in the main sequence evolution stage, and the secondary component is above TAMS, indicating that they are over-luminous. To determine whether the eleven systems are in stable state, the ratio of spin angular momentum to orbital angular momentum (𝐽 𝑠 /𝐽 𝑜 ) and the instability parameters were calculated, and we argued that CRTS J234634.7+222824 is on the verge of a merger.

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“…It is important to study a binary's evolutionary state and dynamic evolution process by researching its period variation, typically through the method of O − C (observed minus calculated) curve analysis using long-term observation data (Qian et al 2013a;Li et al 2018Li et al , 2022c. However, OGLE collections often have fewer than ten data points per period, making it impossible to derive the minimum times required for O − C calculation.…”

Section: Orbital Period Investigationsmentioning

confidence: 99%

A Study of Ten Early-type Contact Binary Stars in the Small Magellanic Cloud

Chu-Qi,

Fu-Xing,

Sheng-Bang

et al. 2023

PASP

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To study early-type binary systems in different evolutionary stages or environments, the Small Magellanic Cloud (SMC) is an ideal laboratory due to its low metallicity compared to that of the Milky Way. We conduct a study on the period changes of the close binary systems with B-type spectral classifications in the SMC using OGLE collections. Ten B-type binaries that show no significant periodic variations based on the current observational data were analyzed. Through O − C analysis, four of the ten early-type binaries show a long-term period decrease, one shows a long-term period increase, and the other five systems are ambiguous due to the limitations of the observational data. Among the period-decreasing systems, two may be mainly caused by mass transfer, while the rest may be caused by angular momentum loss. The Wilson-Devinney code (W-D method) is used to analyze their I-band photometric light curves. According to the W-D results, five early-type binaries are in the deep contact state, three are in the shallow contact state, while two are in the medium contact state, and the temperature ratios of these early-type binaries are all close to unity. The five deep contact binaries are highly unstable systems and therefore serve as important objects for the study of binary mergers. Finally, a discussion on the evolution of early-type binary stars is conducted by combining the analyses of the light curves and the periodic changes of ten early-type binaries, that implies that the majority of early-type binaries in the SMC may form contact binaries from a phase of rapid mass transfer.

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Photometric Study of Two Totally Eclipsing Contact Binaries: V789 Her and V1007 Cas

Cited by 29 publications

References 46 publications

Photometric analysis and evolutionary stages of the contact binary V2790 Ori

Photometric analysis and evolutionary stages of the contact binary V2790 Ori

The study of eleven contact binaries with mass ratios less than 0.1

A Study of Ten Early-type Contact Binary Stars in the Small Magellanic Cloud

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