Period and light-curve study of the contact eclipsing binary V523 Cas

Mohammadi, Mahya; Abedi, Abbas; Riazi, N.

doi:10.1016/j.newast.2015.10.001

Cited by 2 publications

(5 citation statements)

References 17 publications

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“…Except for the residuals before the 1990 scatter, most eclipse timing residuals are fitted well. Another modulated period of P 4 = 18.89(±0.14) yr is shorter than P 4 = 29.35(±0.81) yr deduced by Mohammadi et al (2016). This situation with two 4.…”

Section: V523 Casmentioning

confidence: 59%

“…After the initial residuals were removed by Equation (2), the remained residuals, (O − C) 1 , are displayed in the upper panel of Figure 5(b), not including low-precision photographic and visual data. There exists another cyclic variation, as suggested by Maithong (2021), Mohammadi et al (2016). So we used another light-time effect with zero-point to fit (O − C) 1 .…”

Section: V523 Casmentioning

confidence: 99%

“…Its spectral type is K4V (Bradstreet 1981;Rucinski et al 2003). Zhang & Zhang (2004) and Mohammadi et al (2016) successively reviewed the history of this W-type binary. Milone et al (1985) first performed a radial-velocity study and gave a mass ratio of q sp = 0.42(±0.02) and velocity semi-amplitudes of K 1 = 96(±5) and K 2 = 231(±4) km s −1 .…”

Section: Introductionmentioning

confidence: 99%

“…Photometric studies for V523 Cas have been done at least 15 times in the literature. From the (un)spotted solutions (Zhang & Zhang 2004;Zola et al 2010), the fill-out factor varies from 30.4% (Mohammadi et al 2016) to 4.82% (Zboril & Djurasevic 2006). Based on the eclipse residuals, the orbital period variations have been analyzed by numerous authors, who gave some different results, such as period increase (Zhang & Zhang 2004), together with one cyclic oscillation (Rovithis-Livaniou et al 2003;Samec et al 2004) or two ones (Mohammadi et al 2016;Maithong 2021).…”

Section: Introductionmentioning

confidence: 99%

“…The low-precision spectrum of HI Leo, which was observed by the 2.16 m telescope at XLs of NAOC.different results(Rovithis-Livaniou et al 2003;Mohammadi et al 2016;Maithong 2021). Most of the eclipse times are listed in the literature, such asKreiner et al (2001),Zhang & Zhang (2004), and the O − C gateway.6 …”

mentioning

confidence: 97%

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Light and Period Variations in Two K-type Contact Binaries: HI Leo and V523 Cas

Yang

Wang²,

Yuan³

et al. 2022

Res. Astron. Astrophys.

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We presented a low-precision spectrum for HI Leo, TESS data for V523 Cas, and new photometry for two K-type contact binaries. Comparing their light curves with different observing dates, we found small intrinsic variabilities, such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas. By the Wilson-Devinney Code, we deduced six photometric solutions. The dark spot inV523 Cas may appear on the surface on the more massive component on BJD2458768, while it disappears on BJD 2458779. Our results indicate that two binaries are W-type shallow-contact binaries (f<10%). From the eclipse timing residuals, we found that the orbital periods may continuously increase, accompanied by one to two light-time effects due to additional bodies. Their modulated periods and semi-amplitudes are 25.8(+/-1.0)yr and 0.0066(6)d for HI Leo, 114.8(+/-2.0)yr and 0.0448(12)d, 18.89(+/-0.14)yr and 0.0025(2)d for V523 Cas, respectively. The orbital period secularly increases at a rate of dP/dt=2.86(+/-0.11)10^{-7}d/yr for HI Leo and dP/dt=3.45(+/-0.07)10^{-8}d/yr for V523 Cas, which may be attributed to mass transfer from the secondary to the primary. With mass transferring, the shallow-contact binaries, HI Leo and V523 Cas, will evolve into the broken-contact configurations.

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Section: V523 Casmentioning

confidence: 59%

Section: V523 Casmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 97%

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Light and Period Variations in Two K-type Contact Binaries: HI Leo and V523 Cas

Yang

Wang²,

Yuan³

et al. 2022

Res. Astron. Astrophys.

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X-ray emission of contact binary variables within 1 kpc

Liu

Esamdin

et al. 2022

A&A

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Aims. The X-ray emission of contact binaries (EW-type) is an important facet of such systems. Thus, X-ray emitting EW-type binaries (EWXs) are ideal laboratories for studying the X-ray radiation saturation mechanisms as well as binary evolution. By assembling the largest sample to date of EWXs with periods of less than 1 day from the All-Sky Automated Survey for Supernovae Variable Stars Database and X-ray catalogs from the XMM-Newton and ROSAT missions, we aim to conduct a systematic population study of X-ray emission properties of EWXs within 1 kpc. Methods. We carried out correlation analyses for the X-ray luminosity, logL X , and X-ray activity level log(L X /L bol ) versus the orbital period, P, effective temperature, T eff , metallicity [Fe/H], and the surface gravity log g of EWXs. We investigated the relation between X-ray emission and the mass of component stars in the binary systems. We also performed sample simulations to explore the degeneracy between period, mass, and effective temperature for EWXs. Results. We find strong P-logL X and P-log(L X /L bol ) correlations for EWXs with P < ∼ 0.44 days and we provide the linear parametrizations for these relations, on the basis of which the orbital period can be treated as a good predictor for logL X and log(L X /L bol ). The aforementioned binary stellar parameters are all correlated with logL X , while only T eff exhibits a strong correlation with log(L X /L bol ). Then, EWXs with higher temperature show lower X-ray activity level, which could indicate the thinning of the convective area related to the magnetic dynamo mechanism. The total X-ray luminosity of an EWX is essentially consistent with that of an X-ray saturated main sequence star with the same mass as its primary, which may imply that the primary star dominates the X-ray emission. The monotonically decreasing P-log(L X /L bol ) relation and the short orbital periods indicate that EWXs could all be in the X-ray saturated state, and they may inherit the changing trend of the saturated X-ray luminosities along with the mass shown by single stars. For EWXs, the orbital period, mass, and effective temperature increase in concordance. We demonstrate that the period P = 0.44 days corresponds to the primary mass of ∼ 1.1M , beyond which the saturated X-ray luminosity of single stars will not continue to increase with mass. This explains the break in the positive P-logL X relation for EWXs with P > 0.44 days.

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Period and light-curve study of the contact eclipsing binary V523 Cas

Cited by 2 publications

References 17 publications

Light and Period Variations in Two K-type Contact Binaries: HI Leo and V523 Cas

Light and Period Variations in Two K-type Contact Binaries: HI Leo and V523 Cas

X-ray emission of contact binary variables within 1 kpc

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