• 천문학회지
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• 제45권1호
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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.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.23.2-23.2
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• 2008

We presented the accurate absolute dimensions and distances of fifteen main sequence eclipsing binaries. The photometric and spectroscopic solutions of the binary systems were determined by analyzing light curves and radial velocity curves collected from the literature using the Wilson-Devinney computer code. The fifteen double-line spectroscopic binaries consist of nine detached systems; QX Car, AH Cep, CW Cep, ZZ Cep, XY Cet, RX Her, V451 Oph, VV Pyx and V760 Sco, six semi-detached systems; LY Aur, IU Aur, AO Cas, DM Per, V Pup and HU Tau. The temperatures of the binary systems were determined from their colors using the color-temperature calibrations. Then the temperature of each component star were determined using the temperature ratio which was adjusted from the light curves. We estimated the possible Z values and ages for the detached systems by adopting the Y2 (Yonsei-Yale) stellar evolutionary tracks. The derived distances are in good agreement of the Hipparcos distances whose error of parallax is within 10 %. Finally these well-investigated systems will be used as the standard eclipsing binaries.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.63-67
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• 2012

Observations with milliarsecond resolution using the Navy Optical Interferometer have been obtained for a number of stellar systems which include high-mass binaries, eclipsing binaries, and radio stars. These observations also reveal the previously unseen companions in single-lined spectroscopic binaries via directly measured flux ratios. We will present examples of published and ongoing research efforts of these systems to illustrate how an optical interferometer contributes to our knowledge of stars, their environment, and companions. These studies include a conclusive revealing of the previously unseen companion in the single-lined binary ${\Phi}$ Herculis, the direct determination of orbital parameters in the wide and close orbits of Algol, and revealing the orbit of ${\beta}$ Lyrae with spatially resolved images of the $H{\alpha}$ emission.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.24.1-24.1
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• 2009

V994 Her(ADS 11373 AB, HIP 90483) has been recently known as a quadruple system which consists of double eclipsing and double double-lined spectroscopic binaries (Lee et al. 2008). BV CCD photometric observations of the intricate star system were made during the observing seasons from 2007 to 2008 with the 35cm reflector of the Campus station of the Chungbuk National University Observatory. From the observations a total of 10 times of minimum lights were newly determined. All timings collected, including ours, were intensively analyzed to yield new interesting findings: 1) two eclipsing binaries with the orbital periods of 2.d08326 and 1.d42001 in V994 Her system show possibly apsidal motions with different apsidal periods of 46.y4 and 15.y3, and eccentricities of 0.058 and 0.082, respectively. 2) a light-time effect with a period of 0.y93 may be possible, implying that a third-body be revolving around the binary with the orbital period of 2.d08326.

• 천문학논총
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• 제30권2호
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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.

• Journal of Astronomy and Space Sciences
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• 제16권2호
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• pp.217-266
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• 1999

우리 은하안에서 암혹물질을 찾는 OGLE 프로젝트가 발견한 식쌍성중에서 6개의 대표적인 접촉형쌍성을 선택하여 광도곡선을 분석하여 측광학적인 해를 구하였다. 이들 쌍성들은 태양 근방의 쌍성과 비교할 때 기울기가 낮게 나타났으며, Roche lobe를 채우는 정도인 filling factor는 0.12-0.90로 다양하게 나타났다. 분광관측이 수행되지 않은 쌍성이므로 케플러 궤적과 isochrone 궤적의 교점을 이용한 간접적인 방법으로 쌍성 계열의 질량을 구하고, 이를 기초로 각 쌍성의 절대량과 거리를 구하였다. 이와같은 방법으로 산출한 쌍성들의 거리는 1 kpc - 6 kpc 사이에 분포하는 것으로 나타났다. 이는 주기가 1일 이하인 접촉형 쌍성이 보일 수 있는 한계 거리로 추정하며, 대부분의 접촉형 쌍성은 은하벌지에 속하지 않은 별들이다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2007년도 한국우주과학회보 제16권2호
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• pp.33-33
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• 2007

• Journal of Astronomy and Space Sciences
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• 제24권1호
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• pp.31-38
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• 2007

We have investigated the evolutionary status of 85 Peg within the framework of standard evolutionary theory. 85 Peg has been known to be a visual and spectroscopic binary system in the solar neighborhood. In spite of the accurate information of the total mass (${\sim}1.5M_{\odot}$) and the distance (${\sim}12pc$) from the HIPPARCOS parallax, it has been undetermined an individual mass, therefore the evolved status of the system. Moreover, the coupled uncertainties of chemical composition and age, make matters worse in predicting an evolutionary status of the system. Nevertheless, we computed the various possible models for 85 Peg, and then calibrated stellar parameters by adjusting to the recent observational data. Our modelling computation has included recently updated input physics and stellar theory such as opacity, equation of state, and chemical diffusion. Through a statistical assessment, we have derived a confident parameter set as the best solution which minimized $X^{2}$ within the observational error domain. Most of all, we found that 85 Peg is not a binary system but a triple system with an unseen companion 85 Peg $B_{b}\;{\sim}0.16M_{\odot}$. The aim of the present paper is (1) to provide a complete modelling of the stellar system based on the evolutionary theory, and (2) to constrain the physical dimensions such as mass, metallicity and age.

• 천문학회보
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• 제42권2호
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• pp.38.1-38.1
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• 2017

Symbiotic stars are long-orbital-period interacting binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this contribution, I will present some high-cadence, long-term optical light curves of confirmed and candidate symbiotic stars in the Magellanic Clouds. By careful visual inspection and combined time series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects, trying in particular to distinguish the evolutionary status of the cool component, to provide its first-order pulsation ephemeris and to link all this information with the physical parameters of the binary system as a whole. Finally, I will discuss a new, promising photometric technique, potentially able to discover Symbiotic Stars in the Local Group of Galaxies without the recourse to costly spectroscopic follow-up.

• 천문학회보
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• 제35권1호
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• pp.49.2-49.2
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• 2010

We have presented the evolutionary status of four detached double line spectroscopic eclipsing binaries which are CD Tau, CM Lac, HS Hya and ZZ Boo because the component stars of these binary systems still act as a single star. We determined the absolute dimensions of these binary systems using photometric and spectroscopic solutions from analysis of light curves and radial velocity curves. Using the luminosities, effective temperatures and masses we choose evolutionary tracks of these binary systems. Finally we obtained ages and metallicity of the stars. We found that CM Lac and HS Hya are very young stars and their ages are in range of 0.15-1.05 and 0.22-1.14 Gyrs. For CD Tau and ZZ Boo, they are older than the others and their age in range of 1.95-2.95 and 1.48-1.73 Gyrs.