共查询到20条相似文献，搜索用时 93 毫秒
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The catalogue of the light curve solutions of contact binary stars was updated. Based on the catalogue data we call the attention to a remarkable gap in the temperature distribution of contact binaries which remained unexplained. The absolute dimensions of the components were calculated in a reliable way. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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T. Pribulla S.M. Rucinski D.W. Latham S.N. Quinn M. Siwak J.M. Matthews R. Kuschnig J.F. Rowe D.B. Guenther A.F.J. Moffat D. Sasselov G.A.H. Walker W.W. Weiss 《Astronomische Nachrichten》2010,331(4):397-411
Sixteen new eclipsing binaries have been discovered by the MOST satellite among guide stars used to point its telescope in various fields. Several previously known eclipsing binaries were also observed by MOST with unprecedented quality. Among the objects we discuss in more detail are short‐period eclipsing binaries with eccentric orbits in young open clusters: V578 Mon in NGC 2244 and HD 47934 in NGC 2264. Long nearly‐continuous photometric runs made it possible to discover three long‐period eclipsing binaries with orbits seen almost edge‐on: HD 45972 with P = 28.1 days and two systems (GSC 154 1247 and GSC 2141 526) with P > 25 days. The high precision of the satellite data led to discoveries of binaries with very shallow eclipses (e.g., HD 46180 with A = 0.016 mag, and HD 47934 with A = 0.025 mag). Ground‐based spectroscopy to support the space‐based photometry was used to refine the models of several of the systems (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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K. Karami R. Mohebi 《中国天文和天体物理学报》2007,7(4):558-564
We introduce a new method to derive the orbital parameters of spectroscopic bi-nary stars by nonlinear least squares of (o-c). Using the measured radial velocity data of the four double lined spectroscopic binary systems, AI Phe, GM Dra, HD 93917 and V502 Oph, we derived both the orbital and combined spectroscopic elements of these systems. Our numerical results are in good agreement with the those obtained using the method of Lehmann-Filhe's. 相似文献
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We use the method introduced by Karami & Mohebi (2007), and Karami & Teimoorinia (2007) which enable us to derive the orbital
parameters of the spectroscopic binary stars by the nonlinear least squares of observed vs. curve fitting (o-c). Using the measured experimental data for radial velocities of the four double-lined spectroscopic binary
systems PV Pup, HD 141929, EE Cet and V921 Her, we find both the orbital and the combined spectroscopic elements of these
systems. Our numerical results are in good agreement with those obtained using the method of Lehmann-Filhés. 相似文献
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Z. Bozkurt Ö. L. De&#;irmenci 《Monthly notices of the Royal Astronomical Society》2007,379(1):370-378
Binary systems showing both apsidal motion and light travel time (LTT) effects which cause orbital period changes in close binaries were studied. 15 triple systems showing apsidal motion were found by searching the literature, and a table including the important parameters of these systems was constructed. Six of the systems given in this table were selected and observed photometrically. Existence of both apsidal motion and LTT effects in all selected systems was investigated by means of the analysis of their eclipse times. The mean observed internal structure constants, log = k 2,obs , and contributions to the apsidal motion from the theory of General Relativity and the third/fourth bodies were calculated. The masses of the third/fourth bodies and some characteristics of their orbits were also calculated. 相似文献
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Following a brief history of measurement of eclipsing binary mass ratios from light curves, we show that photometric mass
ratios for overcontact and semi-detached binaries are reliable because the relative stellar radii, R/a, are accurately measured and not, as commonly claimed, because of information in the light variation outside eclipse. We
explore the accuracy of photometric mass ratios by solving synthetic data of typical precisions for a semi-detached and an
overcontact binary for orbital inclinations from 89∘ down into the partial eclipse range. 相似文献
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Slavek M. Rucinski Wenxian Lu 《Monthly notices of the Royal Astronomical Society》2000,315(3):587-594
Radial velocity data for both components of W Crv are presented. In spite of providing full radial-velocity information, the new data are not sufficient to establish the configuration of this important system because of large seasonal light curve perturbations, which prevent a combined light curve/radial-velocity solution. It is noted that the primary minimum is free of photometric perturbations, and this property may help to explain the elusive source of these perturbations. Photometrically, the system appears to be a contact binary with poor or absent energy exchange, but such an explanation – in view of the presence of light curve perturbations – is no more plausible than any one of the semi-detached configurations, with either the more-massive or less-massive components filling the associated Roche lobes. Lengthening of the orbital period and the size of the less-massive component above its main-sequence value, both suggest that the system is the shortest-period (0.388 d) known Algol with non-degenerate components. 相似文献
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Slavek M. Rucinski 《Monthly notices of the Royal Astronomical Society》2009,395(4):2299-2303
The time sequence of 105 spectra covering one full orbital period of AA Dor has been analysed. Direct determination of V sin i for the sdOB component from 97 spectra outside of the eclipse for the lines Mg ii 4481 Å and Si iv 4089 Å clearly indicated a substantially smaller value than estimated before. Detailed modelling of line-profile variations for eight spectra during the eclipse for the Mg ii 4481 Å line, combined with the out-of-eclipse fits, gave V sin i = 31.8 ± 1.8 km s−1 . The previous determinations of V sin i , based on the He ii 4686 Å line, appear to be invalid because of the large natural broadening of the line. With the assumption of the solid-body, synchronous rotation of the sdOB primary, the measured values of the semi-amplitude K 1 and V sin i lead to the mass ratio q = 0.213 ± 0.013 which in turn gives K 2 and thus the masses and radii of both components. The sdOB component appears to be less massive than assumed before, M 1 = 0.25 ± 0.05 M⊙ , but the secondary has its mass–radius parameters close to theoretically predicted for a brown dwarf, M 2 = 0.054 ± 0.010 M⊙ and R 2 = 0.089 ± 0.005 R⊙ . Our results do not agree with the recent determination of Vŭcković et al. based on a K 2 estimate from line-profile asymmetries. 相似文献
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《New Astronomy》2015
Radiation of supersoft X-ray sources (SSS) dominates both the supersof X-ray and the far-UV domain. A fraction of their radiation can be reprocessed into the thermal nebular emission, seen in the spectrum from the near-UV to longer wavelengths. In the case of symbiotic X-ray binaries (SyXBs) a strong contribution from their cool giants is indicated in the optical/near-IR. In this paper I introduce a method of multiwavelength modelling the spectral energy distribution (SED) of SSSs from the supersoft X-rays to the near-IR with the aim to determine the physical parameters of their composite spectra. The method is demonstrated on two extragalactic SSSs, the SyXB RX J0059.1-7505 (LIN 358) in the Small Magellanic Cloud (SMC), RX J0439.8-6809 in the Large Magellanic Cloud (LMC) and two Galactic SSSs, the classical nova RX J2030.5+5237 (V1974 Cyg) during its supersoft phase and the classical symbiotic star RX J1601.6+6648 (AG Dra) during its quiescent phase. The multiwavelength approach overcomes the problem of the mutual dependence between the temperature, luminosity and amount of absorption, which appears when only the X-ray data are fitted. Thus, the method provides an unambiguous solution. It was found that selection of the model (a blackbody or an atmospheric model) is not of crucial importance in fitting the global X-ray/IR SED. The multiwavelength modelling of the SED of SSSs is essential in determining their physical parameters. 相似文献
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The eclipsing binary NN Vir is a short period system showing an EW‐type light curve. Photometric observations of NN Vir were done by Gomez‐Ferrellad & Garcia‐Melendo (1997) at Esteve Duran Observatory. We used photometric data of NN Vir for light curve analysis. The available spectroscopic data of NN Vir is new and we also used the first radial velocity data of this system obtained by Rusinski & Lu (1999) for analysis. The radial velocity and light curves analysis was made with the latest version ofWilson program(1998) and the geometric and physical elements of the system are derived. By searching the simultaneous solutions of the system, we have determined the masses and radii of the components : 1.89(M⊙) and 1.65(R⊙) for the primary component; 0.93(M⊙) and 1.23(R⊙) for the secondary component. We estimated effective temperatures of 7030(K) for the primary and 6977(K) for the secondary component. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The short-period end of the contact binary period distribution based on the All-Sky Automated Survey
Slavek M. Rucinski 《Monthly notices of the Royal Astronomical Society》2007,382(1):393-396
The search volume-corrected period distribution of contact binaries of the W UMa type appears to reflect primarily the constant number ratio of ≃1/500 to the number of stars along the main sequence; there exist no evidence for angular momentum evolution. The maximum in contact binary numbers is located at shorter periods than estimated before, P ≃ 0.27 d . The drop in numbers towards the cut-off at P ≃ 0.215–0.22 d still suffers from the small number statistics while the cut-off itself remains unexplained. Only one out of seven short-period All-Sky Automated Survey variables with P < 0.22 d have been retained in the sample considered here within 8 < V < 13 ; this short-period field-sky record holder at P = 0.2178 d should be studied. 相似文献