• Title/Summary/Keyword: photometric solution

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Orbital Elements and Period Variation of the Eclipsing Binary T LMi (식쌍성 T LMi의 궤도요소와 공전주기 변화에 관한 연구)

  • Oh, Kyu-Dong
    • Journal of Astronomy and Space Sciences
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    • v.4 no.2
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    • pp.69-80
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    • 1987
  • A photometric solutions of T LMi were derived with the Wilson and Devinney model using the BV photoelectric light curves of Okazaki(1977) and orbital period changes are discussed from the all of the collected times a available in the literature. We obtained a variation with a period of $62.^y01$ and an amplitude of $0.^d0425$ form the (O-C) diagram. According to the physical properties of T LMi on the basis of derived photometric solution, it have a doubt the credibility of the existence of "R CMa type".ype".uot;.

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The first photometric analysis of the close binary system NSVS 1461538

  • Kim, Hyoun-Woo;Kim, Chun-Hwey
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.41.2-41.2
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    • 2016
  • The follow-up BVRI photometric observations of NSVS 1461538, which was discovered as an $Algol/{\beta}$ Lyr eclipsing variable by Hoffman, Harrison & McNamara (2009), were performed for three years from 2011 to 2013 by using the 61-cm telescope and CCD cameras of Sobaeksan Optical Astronomy Observatory (SOAO). New light curves have deep depths both of the primary and secondary eclipses, rounded shapes outside eclipses and a strong O'Connell effect, indicating that NSVS 1461538 is a typical W UMa close binary system rather than an $Algol/{\beta}$ Lyr type binary star. A period study with all the timings shows that the orbital period may vary in a sinusoidal way with a period of about 5.6 yr and a small semi-amplitude of about 0.008 d. The cyclical period variation was interpreted as a light-time effect due to a tertiary body with a minimum mass of $0.66M{\odot}$. The first photometric solution with the Wilson-Devinney binary model shows that the system is a W-subtype contact binary with the mass ratio ($q=m_c/m_h$) of 3.46, orbit inclination of 85.6 deg and fill-out factor of 30%. From the existing empirical relationship between parameters, the absolute dimension was estimated. The masses and radii of the component stars are $0.28M{\odot}$ and $0.71R{\odot}$ for the less massive but hotter primary star, respectively, and $0.96M{\odot}$ and $1.21R{\odot}$ for the more massive secondary, respectively. Possible evolution of the system is discussed in the mass-radius and the mass-luminosity planes.

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New Light Curves and Orbital Period Investigations of the Interacting Binary System UV Piscium

  • Jeong, Min-Ji;Han, Wonyong;Kim, Chun-Hwey;Yoon, Joh-Na;Kim, Hyoun-Woo
    • Journal of Astronomy and Space Sciences
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    • v.36 no.2
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    • pp.75-86
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    • 2019
  • UV Psc is a typical RS CVn type system undergoing dynamic chromosphere activity. We performed photometric observations of the system in 2015 and secured new BVR light curves showing well-defined photometric waves. In this paper, we analyzed the light curves using Wilson-Devinney binary code and investigated the orbital period of the system. The combination of our light curve synthesis with the spectroscopic solution developed by previous investigators yielded the absolute parameters as: $M_1=1.104{\pm}0.042M_{\odot}$, $R_1=1.165{\pm}0.025R_{\odot}$, and $L_1=1.361{\pm} 0.041L_{\odot}$ for the primary star, and $M_2=0.809{\pm}0.082M_{\odot}$, $R_2=0.858{\pm}0.018R_{\odot}$, and $L_2=0.339 {\pm}0.010L_{\odot}$ for the secondary star. The eclipse timing diagram for accurate CCD and photoelectric timings showed that the orbital period may vary either in a downward parabolic manner or a quasi-sinusoidal pattern. If the latter is adopted as a probable pattern for the period change, a more plausible account for the cyclic variation may be the light time effect caused by a circumbinary object rather than an Applegate-mechanism occurring via variable surface magnetic field strengths.

Simultaneous Determination of Alkaline Earth Metal Ions by a Conventional High Performance Liquid Chromatographic System

  • Rho, Young-Soo;Choi, Seung-Gi
    • Archives of Pharmacal Research
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    • v.9 no.4
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    • pp.211-214
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    • 1986
  • A simultaneous determination method of alkaline earth metals was attempted with the conventional high performance liquid chromatographic system. Four cations, namely, magnesium, calcium, strontium and barium ion, were injected directly as aqueous solution into an eluent containing copper chloride solution and and were successfully separated and determined on a separating column (Zipax SCX, 4.6 mm i.d. ${\times}25$ cm length, Du Pont, USA) by using a variable wavelength UV detector. The linear calibration curves were obtianed in the range from $1.0{\times}10^{-4}M$ to $5.0{\times}10^{-4}M$ and the correlation coefficient of the calibration curve for each metal of magnesium and calcium in tap water. Alkaline earth metals were determined with the conventional high performance liquid chromatographic system.

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Mass transfer with Asymmetric Light Curve of Contact and Near-Contact Binaries

  • Rittipruk, Pakakaew;Kang, Young-Woon
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.50.1-50.1
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    • 2010
  • We have analyzed times of minima for of 6 binary systems. Three binary systems show period decrease at rate $3.19{\times}10-5$ yr -1 for SV Cen, $1.35{\times}10-7$ yr -1 for RT Scl and $1.14{\times}10-7$ yr -1 for AD Phe. Two systems show period increase $5.696{\times}10-8$ yr -1 for SX Aur and $6.93{\times}10-8$ yr -1 for GO Cyg. One system shows cyclic period variation. We estimated the mass transfer rate for 5 binary systems. Four systems show asymmetric light curves. Two asymmetric light curves (SV Cen and RT Scl) are due to hot spot caused by mass transfer. And two asymmetric light curves (AD Phe and TY Boo) are due to cool spot caused by magnetic activities on the cooler component. We also obtain absolute dimensions from photometric solution and spectroscopic solution by analyzing their light curves and radial velocity curves, which are collected from literatures, using 2007 version Wilson and Deviney computer code.

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Contact and Near-Contact Binaries with co-relation of Mass transfer and Asymmetric Light Curve

  • Rittipruk, Pakakaew;Kang, Young-Woon
    • Bulletin of the Korean Space Science Society
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    • 2010.04a
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    • pp.32.3-32.3
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    • 2010
  • We have analyzed times of minima for six eclipsing binary systems which show asymmetric light curves. We found that five binary systems show period decrease and one system shows cyclic period variation. Three asymmetric light curves (SV Cen, RT Scl and VW Boo) are due to hot spot caused by mass transfer. Other three asymmetric light curves (AD Phe,, EZ Hya and TY Boo) are due to cool spot on the cooler component caused by magnetic activities. We also obtain absolute dimensions from photometric solution and spectroscopic solution by analyzing their light curves and radial velocity curves, collected from literatures, using 2007 version Wilson and Devinney computer code.

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Period Study and Light Curve Synthesis of BD Andromedae

  • Kim, Chun-Hwey;Song, Mi-Hwa;Yoon, Joh-Na;Han, Wong-Yong;Choi, Young-Joon
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.141.1-141.1
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    • 2011
  • New CCD BVR light curves of BD And are presented. Our light curves with nearly equal depths for both primary and secondary eclipses show well-defined photometric waves outside eclipse for all of BVR bandpasses. The orbital period is greatly revised as $0.^d92580519$ which is twice longer than that known previously. Sixteen timings from our observations and thirteen ones from the SuperWASP measurements were calculated. All available timings over 76 years, including ours, were analyzed to figure out the dynamical behavior of the system. It was found that the recent CCD O-C residuals varied in a cyclical way with a period of $9.^y18$ and a semi-amplitude of $0.^d0046$. The secondary period of $9.^y18$ is the most shortest one among those which have been ever found in the short period RS CVn binary stars. The periodic variation most likely arises from the light-travel time effect due to a low-mass ($m_3{\sim}0.88\;M_{\odot}$) tertiary companion moving in an orbit with an large eccentricity ($e_3$=0.70) and a low inclination ($i_3{\sim}28^{\circ}$). The Applegate mechanism could not operate properly in both components because the model parameters require too much large luminosity changes of ${\Delta}L/L_{p,s}$ > 10. The new light curves were synthesized using the 2003 version of Wilson-Divinney code. It was found useful to model two huge spots on the surface of the hotter star and a third-light in order to minimize the residuals from the observations. Astronomical basic parameters were deduced from our photometric solution.

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NEW CCD OBSERVATIONS AND THE FIRST PHOTOMETRIC STUDY OF THE CONTACT BINARY AP UMI

  • AWADALLA, N.S.;HANNA, M.A.;ISMAIL, M.N.;HASSAN, I.A.;ELKHAMISY, M.A.
    • Journal of The Korean Astronomical Society
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    • v.49 no.3
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    • pp.65-71
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    • 2016
  • We obtain the first complete CCD light curves (LCs) of the contact binary AP UMi in the VRI bands and analyzed them by means of the PHOEBE code. A spotted model is applied to treat the asymmetry in the LCs. The LC morphology clearly shows the O'Connell effect and the solution shows an influence of star spots on both components. Such effect of star spots is common between the RS CVn and W UMa chromospherically active stars. Based on the obtained solution of the LCs we investigate the evolutionary state of the components and conclude that the system is a pre-intermediate contact binary (f = 0.29) with mass ratio q = 0.38, and it is an A-type W UMa system where the less massive secondary component is cooler than the more massive primary one.

PHOTOMETRIC OBSERVATIONS AND LIGHT CURVE ANALYSIS OF BL ERIDANI (BL ERIDANI의 측광관측과 광도곡선 분석)

  • Han, Won-Yong;Yim, Hong-Suh;Lee, Chung-Uk;Youn, Jae-Hyuck;Yoon, Joh-Na;Kim, Ho-Il;Moon, Hong-Kyu;Byun, Yong-Ik;Park, Sun-Youp
    • Journal of Astronomy and Space Sciences
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    • v.23 no.4
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    • pp.319-326
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    • 2006
  • We present light curves of a short period binary system BL Eridani. The light curves were observed with VRI filters by a 50cm wide field robotic telescope at Siding Spring Observatory (SSO), equipped with a 2K CCD camera, which was developed by Korea Astronomy and Space Science Institute (KASI), and Yonsei University Observatory(YUO). The photometric observations were made on 6 nights by automatic operation mode and remote observation mode at SSO and KASI in Korea, respectively. We obtained new VRI CCD light curves and new 5 times of minima, and analyzed the light corves with the Wilson & Deviney (1971) binary 2005 version and derived the new photometric solutions. The mass ratio q=0.48 in this study shows different value with earlier investigators. According to the model analysis, it is considered that the BL Eri system is currently undergoing contact stage of the two binary components, rather than near-contact stage.

THE PHOTOMETRIC STUDY FOR THE LONG PERIOD INTERACTION CLOSE BINARY AQ CAS (상호작용이 심한 장주기 근접 쌍성계 AQ Cas의 측광학적 연구)

  • 이용삼;전용우
    • Journal of Astronomy and Space Sciences
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    • v.8 no.1
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    • pp.73-83
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    • 1991
  • UBV light curves of an early type close binary AQ Cas are made with the observations obtained at Yonsei University from 1982 to 1989. Light losses in U are shown at the phase around 0.55 and 0.90 which might be produced by the stream of mass transfer. Four times of minimum light derived from our observations. With the collected minima including ours, new light elements are determined. Phtometric solution with B and V light curves is made by using Wilson-Devinney codes.

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