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1.
本文采用Wilson-Devinney的Roche模型,对两颗短周期食双星ST Car和RY Ind的光变曲线,进行了再分析。结果表明ST Car的测光质比q=0.60,RY Ind的q=0.50,两颗均属分离的不接双星,但它们的小质量次子星几乎充满Roche临界面。两星的测光特性说明,它们可能是Algol演化阶段后的双星。 相似文献
2.
《天文学报》2014,(4)
捅要从2009年到2014年,对食双星DS Psc进行了多色测光和光谱观测,得到了完整覆盖的B、V、R 3色光变曲线以及一批新的光变极小时刻,并首次确定了该双星系统的光谱型.综合已有极小时刻数据,采用O-C方法进行周期分析,得到了新的轨道周期及历元公式.利用Wilson-Devinney方法,对观测所得光变曲线作了拟合分析,首次得到了该双星系统的测光轨道初解.结果表明DS Psc为一个光谱型约为G7V的过相接双星系统.其轨道倾角为66.6°,质量比为2.506.由于其小质量的次子星具有比大质量主子星更高的表面温度,因此DS Psc应属于W次型的W UMa型双星. 相似文献
3.
ζAur双星系统是一类特殊双星系统 ,由一颗晚型红巨星和一颗早型热星组成。红巨星有强大的星风物质损失 ,并在双星系统外部形成一向外膨胀的气壳 ;热星在星风气壳内作轨道运动。由于热星的紫外辐射可以激发星风物质而发光 ,星风物质的向外运动和双星的轨道运动使得ζAur型双星系统的光谱产生特殊周期性变化的PCyg谱线。近十多年来发展起来的、利用运动大气理论计算ζAur型双星系统的PCyg谱线形成 ,以确定这类双星系统中红巨星的星风物质损失率的方法是目前测定物质损失率方法中较为精确的方法。 相似文献
4.
半接双星(semi-detached binary)对于研究相互作用双星的形成和演化有着重要意义。随着大规模时域巡天时代的到来,预计将发现大量此类天体。针对海量的时域观测数据,需要一种快捷的建模工具对半接双星开展自动化光变曲线分析。基于神经网络构建了半接双星快速测光解轨模型。该模型根据光变曲线和已知的主星温度对半接双星的轨道进行建模,获得其轨道倾角、相对半径、质量比和温度比4个基本参数。结果表明,半接双星神经网络解轨模型能够快速地对一条光变曲线建模。在测光误差小于光变曲线振幅1%时,模型对于轨道倾角接近90°、温度比约为0.6、光变振幅为1.84 mag的半接双星的轨道倾角、相对半径、质量比和温度比的测量误差分别为1.251, 0.004, 0.008和0.003。另外,模型应用在开普勒(Kepler)卫星实测光变曲线的结果表明,模型能够较为准确地对脉动食双星的光变曲线进行建模(拟合度可达0.9以上)。此外,该模型作为一个通用工具可以迁移到不同测光巡天项目上。 相似文献
5.
本文给出了1980年1月及1982年3月对44i Boo的UBV及窄波段3940A的光电测光结果,分析了六十五年来该双星的轨道周期变化(O-C)值.认为光变曲线的起伏是由于恒星黑子活动及热斑的影响与双星间气流运动有关;而影响轨道周期的缓变项是由于光时效应引起的,其周期的突变是与物质抛射和恒星上的爆发活动有关. 相似文献
7.
GM Boo是一个已经被发现超过10年的短周期(约0.36天)相接双星。获得了GM Boo在2010到2015年新观测的多波段时序测光数据及其低色散光谱。从光变曲线中提取了19个新的光变极小时刻,并结合历史数据推导出该双星轨道周期增长速率d P/dt=1.06×10~(-7)d·y r~(-1)。Wilson-Devinney程序被用来分析GM Boo的测光轨道解。得出它是一个典型的W次型的过相接双星系统,其质量比约为q~1.22,相接度约为f~11%。模型中添加了2个黑子拟合不对称的光变曲线,说明此系统具有较强的活动性。 相似文献
8.
本文发表了ζAur在1979—1980年食期间进行的六个窄波段(峰值波长为3520,3940,4260,5020,6595(?)_ω和6560(?)_n)及UBV的光电测光结果。根据31个夜晚的有效观测资料得到了食的各不同位相的光变曲线。利用窄波段的光变曲线资料可以客观地确定食的第二、第三接触时刻,从而较准确地定出了食甚时刻,推算出ζAur食的新的历元公式 由图1可以明显地看出食的深度随观测的有效波长的减小而增加。窄波段3940的测光结果与分光观测的CaⅡ的K线变化一致,揭示了ζAur的K型超巨星在1979—1980年食期间色球活动比较激烈。 ζAur的UBV测光给出了关于ζAur系统的食深度及K型子星的V,B-V和U-B值,并与以前的结果作了比较,其结果相当一致。 相似文献
9.
10.
云南-香港宽视场巡天新发现了一个磁活动双星系统,其轨道周期为0.60286 d.利用云南天文台1 m光学望远镜附加CCD (Charge-Coupled Device)相机,观测得到了这个双星系统的V、Rc双色光变曲线,结果表明该系统食外存在明显的测光畸变.借助云南天文台丽江2.4 m望远镜附加云南暗弱天体光谱成像仪(Yunnan Faint Object Spectrograph and Camera, YFOSC)对该双星系统的分光观测,测定了该双星系统主星的视向速度曲线并发现该系统的主星表面存在着强烈的色球活动,从而证明系统的光变曲线畸变源自主星的黑子活动.使用W-D (Wilson-Devinney)程序分析上述观测得到的光变曲线和视向速度曲线,得到了该双星系统的轨道参数以及黑子参数.最后,对该系统的特性进行了讨论并对未来的工作进行了展望. 相似文献
11.
Nabil S. Awadalla 《Experimental Astronomy》1994,5(1-2):21-30
UBV photoelectric light curves of the eclipsing variable DK Cyg, were obtained in four nights of September 1986. They are compared with the previous light curves of the system. The primary shows a transit, so the star maybe classified with the A-type WUMa systems. Two salient points arise from the light curves: first, the secondary maximum is increasing in brightness, and secondly, the secondary minimum is varying in depth. These changing patterns of surface brightness may be due to the instabilities of an energy transfer process between the components. The (O-C) diagram shows a parabolic trend, indicating a seculariy increasing period. 相似文献
12.
Kyu-Dong Oh Chun-Hwey Kim Woo-Baik Lee Ho-il Kim Young Woon Kang 《Monthly notices of the Royal Astronomical Society》2006,366(4):1243-1252
BVR light curves of ZZ Aurigae were obtained with the 60-cm Cassegrain reflector at the Sobaek Observatory, Korea, between 2000 February and 2001 February. All collected times of minimum light, including our observations, were used for the period study. The period variation could be of quasi-sinusoidal form superposed on an upward parabola. A continuous period increase of d P /d t =+2.3 × 10−8 d yr−1 was determined for ZZ Aur. The period of quasi-sinusoidal variation is about ∼26–31 yr. Photometric solutions were found using the Wilson–Devinney method. The Roche configuration of ZZ Aur is that of an Algol-type semidetached system where the primary star nearly fills its Roche lobe and the secondary star fills its lobe. The spot model was used to explain the asymmetry in the light curve known as the O'Connell effect. 相似文献
13.
G. Djura&#;evi&#; I. Vince T. S. Khruzina E. Rovithis-Livaniou 《Monthly notices of the Royal Astronomical Society》2009,396(3):1553-1558
The UBV light curves of the early-type eclipsing binary V448 Cygni, obtained at the Abastumani Astrophysical Observatory from 1964 to 1967, are re-analysed here. The analysis was made assuming the presence of an accretion disc in the system, as inferred from the light-curve shape and spectroscopic characteristics of the system. The Roche model of a binary was used, containing a geometrically and optically thick accretion disc around the hotter and more massive star. By solving the inverse problem, the orbital elements and the physical parameters of the system components and of the accretion disc were estimated. This result is important for understanding the star formation and evolution processes in the systems with massive components. 相似文献
14.
We present here the photometric light curve analyses of the eclipsing binary star DN Aur. The CCD photometry, performed at the Behlen observatory using the 0.76 m automated telescope gave 646 individual data points inV andR bandpass filters. From this data we have determined a new epoch and an orbital period of 0.6168891 days. The published spectral classification is F3.The Wilson-Devinney model was used to derive the photometric solutions. DN Aur is a W UMa type contact binary system. The mass ratio, (q=m
2/m
10.210, where star 2 is eclipsed at the primary minimum) suggests that the system has A-type configuration. The computed light curve has a third light of about 22 percent and a total eclipse in the secondary minimum. A solution with a cool spot on the secondary component is also found. We recommend spectroscopic study of DN Aur even though the light curve analysis show it to be a single line spectroscopic system. Generally contact systems of spectral type F3 have periods ranging from 0.25 to 0.5 days. The longer period of DN Aur suggests that it is an evolved contact system with case A mass transfer. 相似文献
15.
G. Djurašević O. Demircan S. Özdemir M. Tanriver Z. Müyesseroglu H. Ak B. Albayrak 《Astrophysics and Space Science》1997,253(2):265-274
The UBV observations of the massive binary BF Aur were made at the Ankara University Observatory during 1988, 1989 and 1996.
Asymmetry of the light curves, arising from unequal height of successive maxima, indicates that the system is active. By analysing
these observations in the framework of the Roche model (including the presence of bright regions on the components) one obtains
a semidetached configuration of the system, with the cooler secondary component filling its Roche lobe. The analysis of the
light curves yields consistent solutions for mass ratio q = m2/m1 somewhat less than one. The influence of the mass transfer on the change of the system-orbital-period is relatively small.
The upward parabolic character of the O–C diagram (Zhang et al., 1993) indicates a mass transfer from the less massive secondary
to the more massive primary. This inturn requires the less massive secondary to fill its Roche lobe. This is consistent with
our solution. Based on these facts we introduced the following working hypothesis. At the place where the gas stream from
the secondary falls on the primary, relatively small in size but a high temperature contrast active hot-spot (hs) region is
formed. As a result of the heating effect caused by the irradiation of the hot-spot region, on the secondary's side facing
the hot spot a bright-spot (bs) region is formed. The bright-spot region is larger in size but with significantly lower temperature
than the hot spot. This region can be treated as a ‘reflection cap’. By analysing the light curves in the framework of this
working hypothesis the basic parameters of the system and the active regions are estimated. The problem is solved in two stages:
by obtaining a synthetic light curve in the case when the parameters of the corresponding Close Binary (CB) Roche model (Djurašević,
1992a) are given a priori (the direct problem) and by determining the parameters of the given model for which the best fit
between the synthetic light curve and the observations is achieved (the inverse problem) (Djurašević, 1992b).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
New UBV photometry of Algol-Type eclipsing binary star AI Dra andthe absolute physical parameters of this system have been presented.The light curve analysis carried out by the method of differentialcorrections indicates that both components are inside their Roche-Lobes.From combining the photometric solution with spectroscopic data obtainedfrom velocity curve analysis, it has been found that the system consistof a main sequence primary and an evolved (subgiant) secondary. 相似文献
17.
Liu Xue-fu
K. C. Leung
Tan Hui-song
《Chinese Astronomy and Astrophysics》1988,12(4):298-303New UBV photometric observations of IU Aur were made at McDonald Observatory in December 1984 and January 1985, showing that the eclipse depth had kept on increasing and the light minimum time had shown periodic changes. Orbital elements were obtained using the Wilson-Devinney method. The inclination is now close to 90°. The continuous variation of inclination over the last few decades suggests the presence of a third body. Absolute parameters of IU Aur were calculated with the help of Mammano's spectral data. 相似文献
18.
Davood Manzoori Davood Mohammadzadeh Jassur Mir Hojat Kermani 《Astrophysics and Space Science》2006,302(1-4):145-151
New UBV photometry of Algol type binary star U Sge obtained during 1993 are presented, analyzed, and discussed. Wilson-Devinney
code was employed to analyze the light curves. Absolute dimensions of the system were obtained, and positions of both components
on H-R diagram were specified. Finally through color curve analysis absolute visual magnitudes were determined. 相似文献
19.
E. Budding 《Astrophysics and Space Science》1977,46(2):407-428
UBV light curves of the early type close eclipsing binary system SZ Cam have been investigated using recently developed frequency-domain techniques. The combination of both minima in the analysis results in a distinct methodological improvement over the single minimum method discussed hitherto. This improvement has two aspects: (i) increased accuracy of the determined elements, (ii) agreement of the results of the two-minimum method with those of the single-minimum method provides a criterion whereby the self-consistency of the underlying model with its representation of the light curve in the regions between minima by a cosine series and the empirically determined coefficients of such a series may be assessed. Such a self-consistent solution is found, and a further step towards a realistic representation is made by including the photometric perturbations. It is confirmed from these three light curves that the less massive star is overluminous. A probable tendency for the limb-darkening coefficient of the more massive star to increase with decreasing wavelength is also noted. 相似文献
20.
L.C. Watson J.D. Pritchard J.B. Hearnshaw P.M. Kilmartin A.C. Gilmore 《Monthly notices of the Royal Astronomical Society》2001,325(1):143-150
The visual triple system HD 9770 (BB Scl) has been the subject of a four-year programme of UVB ( RI )C photometry and H α échelle spectroscopy. Analysis of the data obtained over that period shows that star B, and probably also star A, of HD 9770 is a binary. The A system comprises a K1V star, which may be in a binary system with another K dwarf. The B system is an eclipsing binary of the BY Dra type in which both stars are chromospherically active. An orbital period of 0.476 525±0.000 013 d has been derived from the light curve in V . Physical parameters derived from analysis of the light curves in UBV ( RI )C are presented. 相似文献