Deep, Low Mass Ratio Overcontact Binary Systems. III. CU Tauri and TV Muscae

Qian, S.‐B.; Yang, Yisi; Soonthornthum, Boonrucksar; Zhu, L.-Y.; He, Jiajia; Yuan, J.-Z.

doi:10.1086/430673

Cited by 85 publications

(34 citation statements)

References 44 publications

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“…This kind of deep contact, low mass ratio binary also appears in many other sources, such as GR Vir Qian et al 2005b). The third light contributions to the total light for the two systems were also obtained.…”

Section: Discussionmentioning

confidence: 61%

Deep, Low Mass Ratio Overcontact Binary Systems. IV. V410 Aurigae and XY Bootis

2005

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The complete charge-coupled device (CCD) light curves in the V, R, and I bands for the eclipsing binary V410 Aur were observed at the Yunnan Observatory in China. Four new light minimum times of V410 Aur were derived from new observations. The photometric solution for V410 Aur was obtained for the first time, while the orbital elements for XY Boo (observed by Binnendijk in 1971) were reanalyzed by using the latest Wilson-Devinney code. The third light contributions to the total lights of the two binaries are obtained. The results reveal that both systems are A-subtype W UMa binaries with low mass ratios and deep degrees of overcontact (i.e., q ph ¼ 0:1428 and f ¼ 52:4% for V410 Aur, and q ph ¼ 0:1855 and f ¼ 55:9% for XY Boo). The photometric mass ratios of the two binaries are very consistent with the spectroscopic mass ratios. By combining the spectroscopic elements with our photometric solutions, the absolute photometric parameters for V410 Aur and XY Boo are (re)determined. Analyzing the orbital periods of the two binaries, it is discovered that their orbital periods show continuous period increases, suggesting that the systems are undergoing mass transfer from the less massive component to the more massive one through the inner Lagrangian point L 1 . This kind of binary, with a low mass ratio, a deep degree of overcontact, and a continuous period increase, may coalesce into a rapidly rotating single star due to tidal instability.

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Section: Discussionmentioning

confidence: 61%

Deep, Low Mass Ratio Overcontact Binary Systems. IV. V410 Aurigae and XY Bootis

2005

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“…Using the photometric data published by B&B, eight times of light minimum were determined and are listed in Table 8. It has been shown in previous papers (e.g., Qian & Yang 2004;Zhu et al 2005;Qian et al 2005aQian et al , 2005bQian et al , 2007Qian et al , 2008 that the orbital periods of all of the investigated high fill-out, extreme mass ratio overcontact binaries are variable. To check whether the orbital period of XY LMi is variable or not, three small telescopes, i.e., the 60 cm and the 1.0 m telescopes at Yunnan Astronomical Observatory and the 80 cm telescope at Xinglong station of the National Astronomical Observatories, were used to monitor eclipse times.…”

Section: Orbital Period Variation Of Xy Leonis Minorismentioning

confidence: 87%

High Fill-Out, Extreme Mass Ratio Overcontact Binary Systems. X. The Newly Discovered Binary Xy Leonis Minoris

Qian

Liu

Zhu

et al. 2011

The Astronomical Journal

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The newly discovered short-period close binary star, XY LMi, has been monitored photometrically since 2006. Its light curves are typical EW-type light curves and show complete eclipses with durations of about 80 minutes. Photometric solutions were determined through an analysis of the complete B, V , R, and I light curves using the 2003 version of the Wilson-Devinney code. XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q = 0.148 and a fill-out factor of f = 74.1%, suggesting that it is in the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components is given. Based on our 19 epochs of eclipse times, we found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt = −1.67 × 10 −7 days yr −1 , which may be caused by mass transfer from the primary to the secondary and/or angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaches the outer critical Roche lobe.

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“… References: (1) Borkovits & Hegedüs (1996); (2) Pych et al (2004); (3) Hoffman et al (2006); (4) Chambliss (1992a); (5) D'Angelo, van Kerkwijk & Rucinski (2006); (6) Kreiner et al (2001); (7) Duerbeck & Rucinski (2007); (8) Qian (2003b); (9) Liu et al (2008); (10) Al‐Naimiy et al (1989); (11) Liu et al (2007); (12) Pribulla et al (2000); (13) Pribulla, Kreiner & Tremko (2003); (14) Qian (2002); (15) Yang et al (2009); (16) Pribulla, Chochol & Parimucha (1999); (17) Qian (2001b); (18) He & Qian (2007); (19) Qian et al (2008c); (20) He & Qian (2008); (21) Qian et al (2008d); (22) Qian et al (2007c); (23) Qian et al (2007d); (24) Qian et al (2007e); (25) Yuan & Qian (2007); (26) Qian et al (2006c); (27) Qian et al (2006d); (28) Zhu et al (2005); (29) Qian et al (2005a); (30) Qian & Yang (2005); (31) Qian et al (2005b); (32) Yang et al (2005); (32) Yang, Qian & Zhu (2004); (34) Qian & Yang (2004). …”

Section: The Most Plausible Explanation Of the Cyclic Period Changesmentioning

confidence: 99%

The most plausible explanation of the cyclic period changes in close binaries: the case of the RS CVn-type binary WW Dra

Liao

Qian

2010

Monthly Notices of the Royal Astronomical Society

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Cyclical period changes are a fairly common phenomenon in close binary systems and are usually explained as due to either the magnetic activity of one or both components (e.g., Applegate 1992) or to the light-travel time effect(LTTE) of a third body. We searched the orbital period changes in 182 EA-type (including the 101 Algol systems used by Hall (1989)), 43 EB-type and 53 EW-type binaries with known both the mass ratio and the spectral type of their secondary components. We reproduced and improved the same diagram as Hall's (1989) according to the new collected data. Our plots do not support the conclusion derived by Hall (1989) that all cases of cyclical period changes are restricted to binaries having the secondary component with spectral types later than F5. The presence of period changes also among stars with secondary component of early type indicates that the magnetic activity is one cause, but not the only one, for the period variation. It is discovered that cyclic period changes, likely due to the presence of a third body are more frequent in EW-type binaries among close binaries. Therefore, the most plausible explanation of the cyclical period changes is the LTTE via the presence of a third body. By using the century-long historical record of the times of light minimum, we analyzed the cyclical period change in the Algol binary WW Dra. It is found that the orbital period of the binary shows a ∼ 112.2yr cyclic variation with an amplitude of ∼ 0.1977days. The cyclic oscillation can be attributed to the LTTE via a third body with a mass no less than 6.43M ⊙ . However, no spectral lines of the third body were discovered indicating that it may be a candidate black hole. The third body is orbiting the binary at a distance shorter than 14.4 AU and it may play an important role in the evolution of this system.

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Deep, Low Mass Ratio Overcontact Binary Systems. III. CU Tauri and TV Muscae

Cited by 85 publications

References 44 publications

Deep, Low Mass Ratio Overcontact Binary Systems. IV. V410 Aurigae and XY Bootis

Deep, Low Mass Ratio Overcontact Binary Systems. IV. V410 Aurigae and XY Bootis

High Fill-Out, Extreme Mass Ratio Overcontact Binary Systems. X. The Newly Discovered Binary Xy Leonis Minoris

The most plausible explanation of the cyclic period changes in close binaries: the case of the RS CVn-type binary WW Dra

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