Different evolutionary pathways for the two subtypes of contact binaries

Zhang, Xu-Dong; Qian, S.‐B.; Liao, Wuping

doi:10.1093/mnras/staa079

Cited by 37 publications

(27 citation statements)

References 140 publications

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“…There have been several evolutionary models of low-mass contact binaries that can explain their orbital period and mass ratio distribution, along with the difference in temperature and luminosity of the individual components (Lucy 1968;Flannery 1976;Yakut & Eggleton 2005;Stepien 2006; Gazeas & Stȩpień 2008;Stępień & Gazeas 2012;Zhang et al 2020). An important aspect of their evolution is the heat transfer in their common convective envelope, which is expected to lead to large-scale circulations of mass and thermal energy in the envelope (Stȩpień 2009).…”

Section: Introductionmentioning

confidence: 99%

Detailed evolutionary models of massive contact binaries – I. Model grids and synthetic populations for the Magellanic Clouds

Menon

Langer

Mink

et al. 2021

Monthly Notices of the Royal Astronomical Society

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The majority of close massive binary stars with initial periods of a few days experience a contact phase, in which both stars overflow their Roche lobes simultaneously. We perform the first dedicated study of the evolution of massive contact binaries and provide a comprehensive prediction of their observed properties. We compute 2790 detailed binary models for the Large and Small Magellanic Clouds each, assuming mass transfer to be conservative. The initial parameter space for both grids span total masses from 20 to 80 M⊙ , orbital periods of 0.6 to 2 days and mass ratios of 0.6 to 1.0. We find that models that remain in contact over nuclear timescales evolve towards equal masses, echoing the mass ratios of their observed counterparts. Ultimately, the fate of our nuclear-timescale models is to merge on the main sequence. Our predicted period-mass ratio distributions of O-type contact binaries are similar for both galaxies, and we expect 10 such systems together in both Magellanic Clouds. While we can largely reproduce the observed distribution, we over-estimate the population of equal-mass contact binaries. This situation is somewhat remedied if we also account for binaries that are nearly in contact. Our theoretical distributions work particularly well for contact binaries with periods <2 days and total masses ⪅45 M⊙ . We expect stellar winds, non-conservative mass transfer and envelope inflation to have played a role in the formation of the more massive and longer-period contact binaries.

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Section: Introductionmentioning

confidence: 99%

Detailed evolutionary models of massive contact binaries – I. Model grids and synthetic populations for the Magellanic Clouds

Menon

Langer

Mink

et al. 2021

Monthly Notices of the Royal Astronomical Society

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show abstract

“…We also found that for the same mass, the luminosity and radius of each component of A-type contact binaries are greater than those of W-type contact systems, indicating that A-type contact binaries are more evolved than W-type contact systems (e.g., Lucy 1976;Wilson 1978). This may mean that the two subtype contact binaries have different formation channels (e.g., Zhang et al 2020b) The orbital angular momentums J orb of the contact binaries were calculated by using the following equation (Christopoulou & Papageorgiou 2013),…”

Section: Discussionmentioning

confidence: 67%

Photometric study and absolute parameters estimation of six totally eclipsing contact binaries

Li,

Xia,

Kim

et al. 2021

Preprint

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High precision CCD observations of six totally eclipsing contact binaries were presented and analyzed. It is found that only one target is an A-type contact binary (V429 Cam), while the others are W-type contact ones. By analyzing the times of light minima, we discovered that two of them exhibit secular period increase while three manifest long-term period decrease. For V1033 Her, a cyclic variation superimposed on the long-term increase was discovered. By comparing the Gaia distances with those calculated by the absolute parameters of 173 contact binaries, we found that Gaia distance can be applied to estimate absolute parameters for most contact binaries. The absolute parameters of our six targets were estimated by using their Gaia distances. The evolutionary status of contact binaries was studied, we found that the A-and W-subtype contact binaries may have different formation channels. The relationship between the spectroscopic and photometric mass ratios for 101 contact binaries was presented. It is discovered that the photometric mass ratios are in good agreement with the spectroscopic ones for almost all the totally eclipsing systems, which is corresponding to the results derived by Pribulla et al. (2003a) andWilson (2005).

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“…Increasing the sample size seems to enhance the sharpness of the distribution peak near the value of 0.3 days. The objects in our catalog tend towards shorter periods, including 27 ultra-short-period objects with periods under the 0.22 days cutoff (Rucinski 1992;Zhang & Qian 2020).…”

Section: Orbital Period and Period Variations As Continuous Quantitiesmentioning

confidence: 97%

“…. Others have tried to explain the W-type phenomenon in terms of stellar evolution within a contact system (see e.g Stȩpień 2009;Yıldız & Dogan 2013;Yıldız 2014;Zhang et al 2020…”

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confidence: 99%

Statistics of 700 individually studied W UMa stars

Latković,

Čeki,

Lazarević

2021

Preprint

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We present a statistical study of the largest bibliographic compilation of stellar and orbital parameters of W UMa stars derived by light curve synthesis with Roche models. The compilation includes nearly 700 individually investigated objects from over 450 distinct publications. Almost 70% of this sample is comprised of stars observed in the last decade that have not been considered in previous statistical studies. We estimate the ages of the cataloged stars, model the distributions of their periods, mass ratios, temperatures and other quantities, and compare them with the data from CRTS, LAMOST and Gaia archives. As only a small fraction of the sample has radial velocity curves, we examine the reliability of the photometric mass ratios in totally and partially eclipsing systems and find that totally eclipsing W UMa stars with photometric mass ratios have the same parameter distributions as those with spectroscopic mass ratios. Most of the stars with reliable parameters have mass ratios below 0.5 and orbital periods shorter than 0.5 days. Stars with longer periods and temperatures above 7000 K stand out as outliers and shouldn't be labeled as W UMa binaries.The collected data is available as an online database at https://wumacat.aob.rs.

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Different evolutionary pathways for the two subtypes of contact binaries

Cited by 37 publications

References 140 publications

Detailed evolutionary models of massive contact binaries – I. Model grids and synthetic populations for the Magellanic Clouds

Detailed evolutionary models of massive contact binaries – I. Model grids and synthetic populations for the Magellanic Clouds

Photometric study and absolute parameters estimation of six totally eclipsing contact binaries

Statistics of 700 individually studied W UMa stars

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