On orbital period changes of two low-mass-ratio and deep-contact binaries: FN Cam and KN Per

Hu, Ke; Jiang, Zhenhua; Yu, Yun-Xia; Fang, Xiang

doi:10.1016/j.newast.2018.01.002

Cited by 6 publications

(4 citation statements)

References 56 publications

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“…In addition, the typical mass-loss rate due to stellar wind for an active dwarf star is about 10 −10 M • yr −1 (Mullan et al 1992) or even lower (Lim & White 1996). It contributes the decrease rate of orbital period at the level of ∼10 −10 d • yr −1 , which is two or three orders of magnitude smaller than the observed ones (typical observed value is 10 −7 d • yr −1 , Hu et al 2018). Thus, the effect of mass loss on orbital period decrease may be neglected for V473 And, V805 And, and EG CVn.…”

Section: Secular Period Changesmentioning

confidence: 75%

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First photometric and orbital period investigations of four W UMa-type eclipse binaries

Meng

Wang

et al. 2022

Publ. Astron. Soc. Aust.

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We presented the first photometric and orbital period investigations for four W Ursae Majoris-type binaries: V473 And, V805 And, LQ Com, and EG CVn. The photometric solutions suggested that V805 And and LQ Com are two total-eclipse contact binaries, while V473 And and EG CVn are partial-eclipse ones. V473 And and LQ Com belong to the A-subtype contact binaries, while V805 And and EG CVn belong to the W subtype. The O’Connell effects found in the light curves of V805 And, LQ Com, and EG CVn can be interpreted as a result of a cool spot on the surface of their less massive and hotter primary components. Based on two different methods, the absolute physical parameters were properly determined. Combining the eclipse timings derived from our observations and survey’s data with those collected from literature, we investigated their orbital period variations. The results show that the orbital periods of V473 And, V805 And, and EG CVn are undergoing a secular decrease/increase superposed a periodic variation, while LQ Com exhibits a possible cyclic period variation with a small amplitude. The secular period changes are caused mainly by the mass transfer between two components, while the cyclic period oscillations may be interpreted as the results of either the light-time effect due to the third body or the cyclic magnetic activity. Finally, we made a statistical investigation for nearly 200 contact binaries with reliable physical parameters. The statistical results suggested that the W-subtype systems are more evolved than the A-subtype ones. Furthermore, the evolutionary direction of A-subtype into W-subtype systems is also discussed. The opposite evolutionary direction seems to be unlikely because it requires an increase of the total mass, the orbital angular momentum, and the temperature differences between two components of a binary system.

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Section: Secular Period Changesmentioning

confidence: 75%

“…to fit their O − C values. Among the four targets, LQ Com should be not undergoing a secular period variation because the coefficient of its quadratic term is 3 orders of magnitude smaller than the typical values for contact binaries (Hu et al 2018). Thus, for LQ Com, we adopted a linear fit.…”

Section: Orbital Period Variationsmentioning

confidence: 94%

First photometric and orbital period investigations of four W UMa-type eclipse binaries

Meng

Wang

et al. 2022

Publ. Astron. Soc. Aust.

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“…They found that KN Per is a DLMROB (q = 0.25; f = 54.49%) with a period of 0.8664606 day. Recently, Hu et al (2018) conducted an O−C analysis and found that the orbital period shows a continuous increase. In this paper, new photometric and spectroscopic investigations of KN Per are presented.…”

Section: Introductionmentioning

confidence: 99%

Photometric and Spectroscopic Studies of the Long-Period Low-Mass-Ratio Deep-Contact Binary KN Per

Gao¹,

Li²,

Cai³

et al. 2022

PASP

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Photometric analysis and spectroscopic study of the long-period low-mass-ratio deep-contact binary KN Per were performed. The light curves of the BV(RI) c band were from the Ningbo Bureau of Education and Xinjiang Observatory Telescope at the Xingming Observatory. Through the analysis of the Wilson–Devinney program, KN Per was found as an A-type low-mass-ratio deep-contact binary (q = 0.236; f = 53.4%). A cool spot applied on the primary component was introduced to explain the unequal maxima of the light curve. Based on the O − C analysis, we found that the rate of the increasing orbital period is P ̇ = 5.12 ± (0.30) × 10−7 day yr−1, meaning the mass transfer from the secondary component to the primary one. By analyzing the spectroscopic data, we detected chromospheric activity emission line indicators, which correspond to the light-curve analysis. Seventy-one long-period (P > 0.5 day) contact binaries, including our target, were collected. The evolutionary states of all collected stars were investigated by the illustrations of mass–radius, mass–luminosity, and log M T –log J o . The relations of some physical parameters were also determined. With the instability parameters of KN Per, we determined that it is a stable contact binary system at present.

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“…Szalai et al (2007) and Pribulla & Rucinski (2006) studied the period change of five systems, including the V870 Ara, to identify the third body, and they could not find sign of multiplicity in the V870 Ara. Ulaş et al (2012) categorized the V870 Ara as late-type contact binary systems; also, Hu et al (2018) listed this system as a deep-contact binary type. In this study, the multi-color CCD light curves in 𝐵, 𝑉, and 𝐼 bands, along with photometric data obtained from the TESS space telescope, are presented.…”

Section: Introductionmentioning

confidence: 99%

BO Ari Light Curve Analysis using Ground-Based and TESS Data

Poro¹,

Zamanpour²,

Hashemi³

et al. 2021

New Astronomy

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New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system taken in filters from Congarinni Observatory in Australia. The new ephemeris is calculated based on seven new determined minima times together with the TESS data and others compiled from the literature. Photometric solutions determined with the Wilson-Devinney (W-D) code combined the Monte Carlo simulation to determine the adjustable parameters' uncertainties. These solutions suggest that V870 Ara is a contact binary system with a mass ratio of 0.244±0.019, a fillout factor of 69±4%, and an inclination of 67.53±0.35 degrees. Absolute parameters of V870 Ara were determined by combining the Gaia EDR3 parallax and photometric elements.

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On orbital period changes of two low-mass-ratio and deep-contact binaries: FN Cam and KN Per

Cited by 6 publications

References 56 publications

First photometric and orbital period investigations of four W UMa-type eclipse binaries

First photometric and orbital period investigations of four W UMa-type eclipse binaries

Photometric and Spectroscopic Studies of the Long-Period Low-Mass-Ratio Deep-Contact Binary KN Per

BO Ari Light Curve Analysis using Ground-Based and TESS Data

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