EB-type contact binary do cas with a large temperature difference

Oh, Kyu-Dong; Ahn, Young Sook

doi:10.1007/bf00643394

Cited by 5 publications

(2 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Though the uncertainties are slightly larger both astrophysical parameters indicate very similar variations as in the cooler component of KR Cyg. DO Cas is also a NCB and its UBV light curves were published by Oh & Ahn (1992). We derived an effective temperature for the hotter star as 8 700 K using the intermediate-band measurements by Hilditch& Hill (1975) and the BVJHK magnitudes given in the SIMBAD database.…”

Section: Search For the Empirical Derivation Of The Albedomentioning

confidence: 99%

Long-term photometric and spectroscopic observations of the near-contact binary KR Cygni

Sipahi¹,

Çakırlı²,

İbanoǧlu³

2012

Preprint

View full text Add to dashboard Cite

We present the multi-color, five-year light curves and the first radial velocities of the near-contact binary system KR Cyg. We derived the masses of the components as 2.88±0.20 M ⊙ and 1.26±0.07 M ⊙ and the radii as 2.59±0.06 R ⊙ and 1.80±0.04 R ⊙ . Analyses of the UBVR light curves and the radial velocities indicate that none of the components exactly fill their corresponding Roche lobes. We have calculated the distance to the system of KR Cyg as 411±12 pc using the observed apparent UBV magnitudes and the bolometric corrections for the component stars. We also searched for the empirical determination of albedo and effective temperature of the cooler, less massive star of KR Cyg, and of two similar near contact binaries AK CMi, and DO Cas. The residuals between the observed and computed fluxes are attributed to the effect of mutual illumination which heats the surface layers of the illuminated star and does vary not only its bolometric albedo but also its limb-darkening coefficient and gravity-brightening exponent. The analysis of the light curves shows that the effective albedos are generally smaller than that expected from an envelope of convective star, being mostly departed from the theoretical value at the B passband. As the reflected light diminishes the effective temperature and, therefore, the luminosity of the irradiated star increase. The observed bluer U-B colors during primary minimum are attributed to the effects of mutual irradiation and multiple scattering processes which may alter several characteristics of these systems.

show abstract

Section: Search For the Empirical Derivation Of The Albedomentioning

confidence: 99%

Long-term photometric and spectroscopic observations of the near-contact binary KR Cygni

Sipahi¹,

Çakırlı²,

İbanoǧlu³

2012

Preprint

View full text Add to dashboard Cite

show abstract

“…Apart from the asymmetric light curves, some contact systems have large depth difference in eclipse (Oh & Ahn 1992;Odell 1996;Zhu et al 2009;Martignoni et al 2009;Siwak et al 2010). This means that there is a large temperature difference between their two components for these systems.…”

Section: Introductionmentioning

confidence: 99%

1SWASP J010313.78+352903.7: A Totally Eclipsing Binary with Components in Poor Thermal Contact

Wang

Zhu²,

Yuan³

2022

Res. Astron. Astrophys.

View full text Add to dashboard Cite

We presented photometry for an EB-type totally eclipsing binary, 1SWASP J010313.78+352903.7, observed with the Xinglong 85-cm telescope on Oct 22, 2021. Light curves in five bands (including the TESS data) were analyzed by employing the W-D method. The photometric solutions show that it is a contact binary with a relatively low mass ratio (q ≃ 0.28), relatively large fill-out factor (f ≃ 40%) and large temperature difference (∆ T ≃ 1700K). Max.I-Max.II is up to about 9% of variable light amplitude of the asymmetric light curves. It is well described by double-hot spots model on the surface of the cooler secondary. The two hot spots are both in growing and evolving. They may be caused by two different mechanics, i.e. magnetic stellar activity and mass transfer. The large temperature difference between the two contact components indicates that they share a non-thermal equilibrium common envelope.

show abstract