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

Yang, Yuangen; Qian, S.‐B.; Zhu, L.-Y.

doi:10.1086/496880

Cited by 45 publications

(9 citation statements)

References 19 publications

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“… (1) Pribulla et al (1999); (2) Gazeas et al (2005); (3) Szalai et al (2007); (4) Gazeas et al (2006); (5) Şenavcı et al (2008); (6) Yakut & Eggleton (2005); (7) Zoła et al (2005); (8) Maceroni & vant Veer (1996); (9) Yang, Qian & Zhu (2005); (10) Zhang, Zhang & Deng (2005). …”

Section: The Minimum Mass Ratiounclassified

On the minimum mass ratio of W UMa binaries

Jiang¹,

Han²,

Wang³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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Using Eggleton's stellar evolution code, we study the minimum mass ratio ($q_{\rm min}$) of W Ursae Majoris (W UMa) binaries that have different primary masses. It is found that the minimum mass ratio of W UMa binaries decreases with increasing mass of the primary if the primary's mass is less than about 1.3$M_{\rm \odot}$, and above this mass the ratio is roughly constant. By comparing the theoretical minimum mass ratio with the observational data, it is found that the existence of low-$q$ systems can be explained by the different structure of the primaries with different masses. This suggests that the dimensionless gyration radius ($k_1^2$) and thus the structure of the primary is very important in determining the minimum mass ratio. In addition, we investigate the mass loss during the merging process of W UMa systems and calculate the rotation velocities of the single stars formed by the merger of W UMa binaries due to tidal instability. It is found that in the case of the conservation of mass and angular momentum, the merged single stars rotate with a equatorial velocity of about $588\sim819$ km s$^{-1}$, which is much larger than their break-up velocities ($v_{\rm b}$). This suggests that the merged stars should extend to a very large radius (3.7$\sim$5.3 times the radii of the primaries) or W UMa systems would lose a large amount of mass (21$\sim$33 per cent of the total mass) during the merging process. If the effect of magnetic braking is considered, the mass loss decreases to be 12$\sim$18 per cent of their total masses. This implies that the significant angular momentum and mass might be lost from W UMa systems in the course of the merging process, and this kind of mass and angular momentum loss might be driven by the release of orbital energy of the secondaries, which is similar to common-envelope evolution.Comment: 16 pages, 3 figures, Accepted for publication in Monthly Notice

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Section: The Minimum Mass Ratiounclassified

On the minimum mass ratio of W UMa binaries

Jiang¹,

Han²,

Wang³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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“…R 1 – radius of the primary; R 2 – radius of the secondary; T 1 – effective temperature of the primary; T 2 – effective temperature of the secondary. References in Table 1: (1) Awadalla & Hanna (2005); (2) Gazeas et al (2006); (3) Özdemir et al (2002); (4) Yakut et al (2005); (5) Zoła, Niarchos & Dapergolas (2005); (6) Yang, Qian & Zhu (2005); (7) Szalai et al (2007).…”

Section: Energy Transfer In W Uma Systemsmentioning

confidence: 99%

Energy transfer and its effects on the secondaries in W Ursae Majoris type contact binaries

Jiang¹,

Han²,

Jiang³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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Based on the physical parameters of 133 W Ursae Majoris (W UMa) type contact binaries, energy transfer and its effects on the secondaries in W UMa contact binaries are investigated. Relations are given between the mass ratio (q) for W UMa contact binaries and the relative energy transfer rates, i.e. U1, the ratio of the transferred luminosity to the surface luminosity of the primary, and U2, the ratio of the transferred luminosity to the nuclear luminosity of the secondary. The theoretical curves(U1 versus q and U2 versus q) are derived based on various assumptions: that the two components in each W UMa system are nearly identical in effective temperature and just fill their inner Roche lobes, and the primaries are zero‐age main‐sequence stars. Although these curves can reflect the distribution of U1 and U2 versus q, some observational systems deviate significantly from these curves. This results mainly from the difference in effective temperatures of the components of W UMa systems. The radius and the density of the secondary are related to the relative energy transfer rate U2: the higher U2, the greater the expansion and the lower the density of the secondary in a W UMa system. In addition, it is found that the temperature difference of W UMa binary components is correlated with the relative energy transfer rate U1 and decreases with increasing U1. This might suggest that there is a thermal coupling between the two components in W UMa contact binaries, and that the classification of W UMa contact binaries into A or W types depends on the energy transfer from the primary to the secondary. The temperature difference of W UMa binary components is poorly correlated with the mass of the primary. This suggests that the properties of the common envelope of a W UMa contact binary might not have a significant effect on the energy transfer between the two components.

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“…The found record-breaking period increaseṖ = 1.67(5) × 10 −9 = 5.3 s per century was explained by mass transfer of 1.34 × 10 −7 M yr −1 from the secondary to the primary component. The results were confirmed and improved by Yang et al (2005), who foundṖ = 1.711(6) × 10 −9 = 5.4 s per century on the basis of standard O-C analysis of 54 minima times.…”

Section: Xy Bootismentioning

confidence: 63%

“…In their calculations of the quadratic ephemeris of XY Boo, Wilson & Van Hamme (2014) combined phase information hidden in BV LCs obtained by Binnendijk (1971), Winkler (1977), and Awadalla & Yamasaki (1984), further RV curves of McLean & Hilditch (1983), all times of minima listed in Yang et al (2005), and other 33 minima timings collected in Table 1 of their article covering the interval 2005-09. Using all of those data, they found the mean period increaseṖ = 1.6348(8) × 10 −9 = 5.159(24) s per century.…”

Section: Xy Bootismentioning

confidence: 99%

Phenomenological modelling of eclipsing system light curves

Mikulášek¹

2015

A&A

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Context. The observed light curves of most eclipsing binaries and stars with transiting planets can be described well and interpreted by current advanced physical models that also allow for determining many of the physical parameters of eclipsing systems. However, for several common practical tasks, there is no need to know the detailed physics of a variable star, but only the shapes of their light curves or other phase curves.Aims. We present a set of phenomenological models for the light curves of eclipsing systems. Methods. We express the observed light curves of eclipsing binaries and stars, which are transited by their exoplanets orbiting in circular trajectories, by a sum of special, analytical, few-parameter functions that enable fitting their light curves with an accuracy of better than 1%. The proposed set of phenomenological models of eclipsing variable light curves were then tested on several real systems. For XY Bootis, we also give a detailed comparison of the results obtained using our phenomenological modelling with those found using available physical models. Results. We demonstrate that the proposed phenomenological models of transiting exoplanet and eclipsing binary light curves applied to ground-based photometric observations yield results compatible with those obtained by applying more complex physical models. Conclusions. The suggested phenomenological modelling appears useful for solving a number of common tasks in the field of eclipsing variable research.

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

Cited by 45 publications

References 19 publications

On the minimum mass ratio of W UMa binaries

On the minimum mass ratio of W UMa binaries

Energy transfer and its effects on the secondaries in W Ursae Majoris type contact binaries

Phenomenological modelling of eclipsing system light curves

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