Two Contact Binaries with Mass Ratios Close to the Minimum Mass Ratio

Abstract The cutoff mass ratio is under debate for contact binaries. In this paper, we present the investigation of two contact binaries with mass ratios close to the low mass ratio limit. It is found that the mass ratios of VSX J082700.8+462850 (hereafter J082700) and 1SWASP J132829.37+555246.1 (hereafter J132829) are both less than 0.1 (q ∼ 0.055 for J082700 and q ∼ 0.089 for J132829). J082700 is a shallow contact binary with a contact degree of ∼19%, and J132829 is a deep contact system with a fill-out factor of ∼70%. The O − C diagram analysis indicated that the two systems manifested long-term period decreases. In addition, J082700 exhibits a cyclic modulation which is more likely resulting from the Applegate mechanism. In order to explore the properties of extremely low mass ratio contact binaries (ELMRCBs), we carried out a statistical analysis on contact binaries with mass ratios of q ≲ 0.1 and discovered that the values of J spin/J orb of three systems are greater than 1/3. Two possible explanations can interpret this phenomenon. One explanation is that some physical processes, unknown to date, are not considered when Hut presented the dynamic stability criterion. The other explanation is that the dimensionless gyration radius (k) should be smaller than the value we used (k 2 = 0.06). We also found that the formation of ELMRCBs possibly has two channels. The study of evolutionary states of ELMRCBs reveals that their evolutionary states are similar with those of normal W UMa contact binaries.

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Long-term orbital period behaviour of low mass ratio contact binaries GR Vir and FP Boo

10.1063/1.4976442 ◽

2017 ◽

Cited By ~ 1

Author(s):

Halil Çetinkaya ◽

Faruk Soydugan

Keyword(s):

Orbital Period ◽

Mass Ratio ◽

Contact Binaries ◽

Low Mass ◽

Low Mass Ratio

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Searching for eclipsing binaries in the area of RA: 02h21m36s, Dec: +57○11′32″

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2170 ◽

2020 ◽

Vol 497 (3) ◽

pp. 3381-3392

Author(s):

Di-Fu Guo ◽

Kai Li ◽

Xing Gao ◽

Dong-Yang Gao ◽

Zhi-Jian Xu ◽

...

Keyword(s):

Binary Systems ◽

Eclipsing Binaries ◽

Light Curves ◽

Mass Ratio ◽

Contact Binaries ◽

Contact Binary ◽

Low Mass ◽

Low Mass Ratio ◽

Period Decrease ◽

Cross Matching

ABSTRACT By analysing the data observed by the Comet Search Programme telescope at Xingming Observatory from 2018 October 11 to 2018 December 19, 24 eclipsing binaries were identified. By cross-matching with the VSX (AAVSO) website, we found that four binaries are newly discovered. By analysing the Transiting Exoplanet Survey Satellite (TESS) data, the light curves of 17 binaries were obtained. First photometric solutions of 23 binaries were obtained by simultaneously analysing all the light curves, except for NSVS 1908107 (first analysed by Pan et al.). Based on the photometric solutions, nine binaries belong to detached binary systems, ten binaries belong to semidetached binary systems, and five binaries belong to contact binary systems. Two W-subtype low-mass ratio contact binaries (the less massive components are hotter), with total eclipsing light curves, were identified: Mis V1395 is a deep contact binary (q = 0.150, $f=80{{\ \rm per\ cent}}$), while NSVS 1917038 is a low-mass ratio binary with an unexpectedly marginal contact degree (q = 1/6.839 = 0.146, $f=4{{\ \rm per\ cent}}$). The total eclipsing detached binary GSC 03698-00022 has an extremely low mass ratio of q = 0.085. The Algol-type binary NSVS 1908107 is also found to have an extremely low mass ratio of q = 0.081. The Algol-type binary DK Per exhibits a continuous period decrease at a rate of dP/dt = −1.26 × 10−7 d yr−1, which may result from the orbital angular momentum loss. Based on the light curves obtained from the TESS data, a pulsating binary candidate (NSVS 1913053) was found.

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Distribution of physical parameters for 380 contact binaries in the Kepler field

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa104 ◽

2020 ◽

Vol 72 (6) ◽

Author(s):

Xu-Zhi Li ◽

Liang Liu ◽

Li-Ying Zhu

Keyword(s):

Binary Systems ◽

Large Mass ◽

Eclipsing Binaries ◽

Physical Parameters ◽

Mass Ratio ◽

Eclipsing Binary ◽

Contact Binaries ◽

Contact Binary ◽

Low Mass ◽

Low Mass Ratio

Abstract We present the physical parameters (p, T, q, i, f) of 380 Kepler contact binary systems (hereafter called CBs). A statistical study on the CBs is carried out based on a Kepler photometric database. Our samples were selected from the Kepler Eclipsing Binary Catalogue of EW-type eclipsing binaries with periods around 0.2–1 d and amplitudes greater than $5\%$. The physical parameters were obtained by fitting the Kepler light curves with the Wilson–Devinney eclipsing binary modeling program. Our sample of CBs contains 160 A-type and 220 W-type CBs. The fill-out factor distribution indicated that CBs generally have shallow fill-out; the proportion of CBs with fill-out factors less than $30\%$ is around $70\%$, which may be related to the formation and evolution of the CBs. The period–temperature relationship of CBs is consistent with previous studies, which is the well-known period–color relationship. The distribution between mass ratio and fill-out factor can provide some information for studying the deep, low-mass ratio contact binaries and CBs which have a large mass ratio. The mass–radius diagram shows that there is a similar linear relationship between the primary and secondary stars while the primary stars are located almost on the ZAMS line; this could be related to the internal nuclear reaction within the primary and secondary stars.

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The first photometric analysis of two low mass ratio totally eclipsing contact binaries: TIC 393943031 and TIC 89428764

Research in Astronomy and Astrophysics ◽

10.1088/1674-4527/ac4705 ◽

2021 ◽

Author(s):

Yanke Tang ◽

Yani Guo ◽

Kai Li ◽

Ning Gai ◽

Zhikai Li

Keyword(s):

Mass Transfer ◽

Primary Component ◽

Mass Ratio ◽

Photometric Analysis ◽

Angular Momenta ◽

Contact Binaries ◽

Contact Binary ◽

Low Mass ◽

Low Mass Ratio ◽

First Time

Abstract PhotometricanalysisofthecontactbinariesTIC393943031andTIC89428764was carried out usingTESS and SuperWASP data for the first time. Using Wilson-Devinneycode, we have discovered TIC 393943031 is a low-mass-ratio deep contact binary with a fillout factor of 50.9(±1)% and a mass ratio of q = 0.163 ± 0.001. TIC 89428764 is a medium and low-mass-ratio contact binary with a fillout factor of 34.5(±1)% and a mass ratio of q = 0.147±0.001. Furthermore, the period study reveals both the stars exhibit continuously increasing periods, the increasing rate is 4.21×10−7day ·year−1for TIC 393943031while 6.36 × 10−7day · year−1for TIC 89428764. The possible reason is mass transfer from the secondary component to the primary component for both the stars. Meanwhile, we discussed their evolutionary phases and orbital angular momenta.

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