1SWASP J074658.62+224448.5: A LOW MASS-RATIO CONTACT BINARY AT THE PERIOD CUTOFF

2015 ◽  
Vol 149 (5) ◽  
pp. 169 ◽  
Author(s):  
L.-Q Jiang ◽  
S.-B. Qian ◽  
J. Zhang ◽  
X. Zhou
2021 ◽  
Vol 922 (2) ◽  
pp. 122
Author(s):  
Kai Li ◽  
Qi-Qi Xia ◽  
Chun-Hwey Kim ◽  
Shao-Ming Hu ◽  
Di-Fu Guo ◽  
...  

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.


2019 ◽  
Vol 19 (4) ◽  
pp. 056 ◽  
Author(s):  
Jia-Jia He ◽  
Sheng-Bang Qian ◽  
Boonrucksar Soonthornthum ◽  
Amornrat Aungwerojwit ◽  
Niang-Ping Liu ◽  
...  

2020 ◽  
Vol 497 (3) ◽  
pp. 3381-3392
Author(s):  
Di-Fu Guo ◽  
Kai Li ◽  
Xing Gao ◽  
Dong-Yang Gao ◽  
Zhi-Jian Xu ◽  
...  

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.


2018 ◽  
Vol 156 (5) ◽  
pp. 199 ◽  
Author(s):  
T. Sarotsakulchai ◽  
S.-B. Qian ◽  
B. Soonthornthum ◽  
X. Zhou ◽  
J. Zhang ◽  
...  

New Astronomy ◽  
2016 ◽  
Vol 46 ◽  
pp. 73-77 ◽  
Author(s):  
N. Erkan ◽  
B. Ulaş

New Astronomy ◽  
2008 ◽  
Vol 13 (7) ◽  
pp. 468-472 ◽  
Author(s):  
H.V. Şenavcı ◽  
R.H. Nelson ◽  
İ. Özavcı ◽  
S.O. Selam ◽  
B. Albayrak

New Astronomy ◽  
2016 ◽  
Vol 44 ◽  
pp. 12-16 ◽  
Author(s):  
W. Kriwattanawong ◽  
O. Tasuya ◽  
P. Poojon

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