• Title/Summary/Keyword: Eclipsing binaries

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Photoelectric Observation of the Long-Period Eclipsing Binaries at Yonsei University Observatory

  • Nha, Il-Seong;Lee, Yong-Sam;Chun, Yong-Woo;Kim, Ho-Il;Kim, Young-Soo
    • Journal of Astronomy and Space Sciences
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    • v.3 no.1
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    • pp.1-13
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    • 1986
  • A long-term project(ten-year ; 1982-92) for the photoeletric observation in the UBV passbands of selected eclipsing binaries with P$\geq$10 days has initiated at Yonsei University Observatory using 40-cm and 61-cm reflectors. the instrumentatio used and the observation techniques and the reduction procedures applied to this investiagation are described. Out of 39 program stars, successful results have been obtained during our first two years for the 11 stars listed below, with the orbital period in days in the parenthesis, and the incomplete light curves of these stars are presented. SX Cas (36.57) AQ Cas (11.72) UU Cnc (96.71) RY Gem (9.30) V373 Cas (13.42) NY Cep (15.28) RX Cas (32.32) V396 Cas (15.28) ZZ Cnc (25.60) Zet Aur (982.2) Eps Aur (9885.) For the rest of the stars, the observations made in the first two years are not sufficient to attempt any meaning light curve construction ; some of the data are too fragmented and others show large scatter.

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Apsidal motions of 90 eccentric binary systems in the Small Magellanic Cloud

  • Hong, Kyeongsoo;Lee, Jae Woo;Kim, Seung-Lee;Koo, Jae-Rim;Lee, Chung-Uk
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.42.1-42.1
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    • 2016
  • We examined thousands of light curves of stars brighter than 18.0 mag in I band and less than mean magnitude error of 0.1 mag in V band from the OGLE-III eclipsing binary catalogue, and found 90 new binary systems exhibiting apsidal motion. In this study, the samples of apsidal motion stars in the SMC were increased by 250 percent than previously known. In order to determine the period of the apsidal motion for the binaries, we analysed in detail both light curves and eclipse timings using the MACHO and OGLE photometric database obtained for about 20 yrs. For the eclipse timing diagrams of the systems, new times of minimum light were derived from the full light curve combined at intervals of one yr from the survey data. The binaries presented in this paper have apsidal motion periods in the range of 12-918 yrs. An additional short-term oscillation was detected in five systems (OGLE-SMC-ECL-1634, 1947, 3035, 4946, and 5382), which most likely arise from the existence of a third body orbiting each eclipsing binary. All of the selected systems can be used for the statistical study of the interior structure of the stars in the SMC through their apsidal motions due to the homogeneous data and consistent analysis methods.

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SPECTROSCOPIC ANALYSIS OF THE R CANIS MAJORIS BINARY SYSTEM

  • A-THANO, N.;MKRTICHIAN, D.E.;KOMONJINDA, S.
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.231-232
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    • 2015
  • R Canis Majoris is a bright, short-period ($1^d$.1359) Algol-type eclipsing binary. For a long time, it was considered to be a low-mass binary star with $M_1=1.1M_{\odot}$ and $M_2=0.17M_{\odot}$ primary and secondary components, respectively (Tomkin, 1985). Glazunova, Yushchenko & Mkrtichian (2009) found new masses for the primary and secondary components of $M_1=1.81M_{\odot}$ and $M_2=0.23M_{\odot}$, respectively and resolved a long-standing problem with the low masses of components for this binary. Budding and Butland (2011) confirmed the results of Glazunova, Yushchenko & Mkrtichian and obtained improved orbits and masses. New spectroscopic observations of R CMa were done during 8 nights on December 2012 with the 2.4-meter telescope of the Thai National Observatory (TNO) and fibre-fed medium resolution echelle spectrograph. We obtained new, accurate orbital radial velocities of the two components of this binary system. Results of these investigations and the new orbital parameters are presented.

Asymmetric Light curves of Contact and Near-Contact Binaries

  • Rittipruk, Pakakaew;Kang, Young-Woon
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.143.1-143.1
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    • 2012
  • We attempt to investigate the main reason of the asymmetrical light curves of contact and near-contact eclipsing binary base on the hypothesis that cool spot was produced on late type star while hot spot was produced from transferred material from their companion star hitting surface. We select 7 eclipsing binary systems which showed asymmetric light curves and mass transfer. Period variation and mass transfer rate were obtained from O-C diagram. Radial velocity curves and light curves of those 7 eclipsing binary system were adopted from available literature in order to obtain the absolute dimension. For four contact eclipsing binary system (AD Phe, EZ Hya, AG Vir and VW Boo), their component stars belonged to spectral type G to K was fitted by cool spot model. While the other two near-contact systems (RT Scl and V1010 Oph) and one contact system (SV Cen) was fitted by cool spot model. The densities of the materials are adopted from stellar model which calculate by stellar structure code. The calculated spot temperature turns out to agree with the photometric solution but there are no correlate between period variation rate and type of spot.

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VARIABLE STARS IN THE REGION OF CYG OB3 ASSOCIATION CENTERED ON THE OPEN CLUSTER NGC 6871 II (산개성단 NGC 6871을 중심으로 한 Cyg OB3 성협 영역의 변광성 II)

  • Jeon, Young-Beom;Park, Yoon-Ho;Lee, UiRyeol;Kim, DongHyeon;Jang, Hyeeun;Cho, SungYoon
    • Publications of The Korean Astronomical Society
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    • v.28 no.3
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    • pp.83-93
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    • 2013
  • This is the second paper on a systematic search for variable stars in Cyg OB3 region. In this paper we present the observational properties of 46 variable stars found in the region. Among them, 27 are eclipsing binaries and others are semi-long periodic or slow irregular variables. Only 5 are known variables and the rest are newly discovered ones. We have obtained the period and amplitude of 20 eclipsing binaries using the phase fitting method, and present the light curves of 46 variable stars.

V608 CASSIOPEIAE: A W UMA-TYPE ECLIPSING BINARY WITH TWO POSSIBLE CIRCUMBINARY COMPANIONS

  • Park, Jang-Ho;Lee, Jae Woo
    • Journal of The Korean Astronomical Society
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    • v.55 no.1
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    • pp.1-9
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    • 2022
  • We present the photometric properties of V608 Cas from detailed studies of light curves and eclipse timings. The light curve synthesis indicates that the eclipsing pair is an overcontact binary with parameters of ∆T = 155 K, q = 0.328, and f = 26%. We detected the third light ℓ3, which corresponds to about 8% and 5% of the total systemic light in V and R bands, respectively. Including our 6 timing measurements, a total of 38 times of minimum light were used for a period study. It was found that the orbital period of V608 Cas has varied in some combination of an upward parabola and two periodic variations. The continuous period increase with a rate of +3.99 × 10-7 d yr-1 can be interpreted as a mass transfer from the secondary component to the primary star at a rate of 1.51 × 10-7 M yr-1. The periods and semi-amplitudes of the two periodic variations are about P3 = 16.0 yr and P4 = 26.3 yr, and K3 = 0.0341 d and K4 = 0.0305 d, respectively. The most likely explanation of both cycles is a pair of light-traveling time effects operated by the possible presence of third and fourth components with estimated masses of M3 = 2.20 M and M4 = 1.27 M in eccentric orbits of e3 = 0.66 and e4 = 0.52. Because the contribution of ℓ3 is very low compared to the estimated masses of two circumbinary objects, they can be inferred as very faint compact objects.

THE REFLECTION EFFECT ON THE ECLIPSING BINARY BY THE WILSON AND DEVINNEY'S MODEL AND RUSSELL AND RUSSELL AND MERRILL'S MODEL (Wilson과 Devinney의 모델과 Russell과 Merrill의 모델에 의한 식쌍성의 반사 효과)

  • 최성희;강영운
    • Journal of Astronomy and Space Sciences
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    • v.9 no.1
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    • pp.30-40
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    • 1992
  • The reflection effect on three types of eclipsing binaries has been analyzed based on the Wilson and Devinney's model and Russell and Merrill's model. The reflection effect was displayed on the theoretical light curves for the various conditions using the Wilson and Devinney's light curve program. Two models were compared after the rectifing the theoretical light curves including the reflection effect with the Russell and Merrill's method. The result shows that two models have an agreement on the reflection effect just in cases of the small difference in temperature adn albedo between two stars in the system.

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CHARACTERISTICS OF PERIOD VARIATION OF ECLIPSING BINARY STAR (식쌍성의 공전주기 변화에 관한 특성 -EA 형과 준분리형 중심으로-)

  • 오규동
    • Journal of Astronomy and Space Sciences
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    • v.10 no.1
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    • pp.44-85
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    • 1993
  • Among the EA and semi-detached type binary systems, nineteen eclipsing binaries were investigated for their period variations from all of the collected times of minima available in the literature. After the period study of each individual binary, an attempt was made, in view of the linear ephemeris showing abrupt change in period, to give a physical interpretation to the combined observational result. The correlation between period changes and physical parameters of the investigated binary systems are discussed.

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PRELIMINARY RESULTS FOR SHORT-PERIOD VARIABILITY SURVEY (SPVS) : NEW FIELD VARIABLE STARS (단주기변광성 탐사의 예비결과 : 시험영역에서 발견된 새로운 변광성)

  • Jeon, Young-Beom;Nam, Ki-Hyung;Park, Yoon-Ho;Lee, Kyung-Hoon
    • Publications of The Korean Astronomical Society
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    • v.22 no.4
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    • pp.141-149
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    • 2007
  • Preliminary time-series observations for short-period variability survey (SPVS) were carried out using a 155mm refractor and a $2k{\times}3k$ CCD camera at Bohyunsan Optical Astronomy Observatory. We found 21 new variable stars in the $90'{\times}60'$ test field region : 9 eclipsing binary stars, $5{\delta}$ Scuti type stars, a ${\gamma}$ Doradus type star, and 6 long period variables. The observing field center is R.A. $05^h\;00^m\;00^s$, DEC. $50^{\circ}\;00'\;00"$ (J2000.0). The period and amplitude ranges for the short-period variables, i.e., ${\delta}$ Scuti stars, were 0.052day - 0.107day and 0.012mag - 0.064mag, respectively.

NEW ORBITAL PARAMETERS AND RADIAL VELOCITY CURVE ANALYSIS OF SPECTROSCOPIC BINARY STARS

  • Ghaderi, Kamal;Pirkhedri, Ali;Rostami, Touba;Khodamoradi, Salem;Fatahi, Hedayat
    • Journal of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.1-6
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    • 2012
  • We use a Probabilistic Neural Network (PNN) technique to derive the orbital parameters of spectroscopic binary stars. Using measured radial velocity data of five double-lined spectroscopic binary systems (i.e., EQ Tau, V376 And, V776 Cas, V2377 Oph and EE Cet), we find the corresponding orbital and spectroscopic elements. Our numerical results are in good agreement with those obtained by other groups via more traditional methods.