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类太阳G型相接双星的观测与研究
Alternative TitleThe Observation and Study on G-type Solar-like Contact Binaries
王晶晶
Subtype硕士
Thesis Advisor钱声帮
2012-06
Degree Grantor中国科学院研究生院(云南天文台)
Place of Conferral北京
Degree Discipline天体物理
Keyword类太阳 相接双星 测光观测 黑子活动 第三天体
Abstract类太阳G型子星具有与太阳类似的内部结构,由于较快自转和深层对流,它们表现出较为强烈的类太阳活动:黑子、耀斑等。本文首先介绍了类太阳G型相接双星的定义、观测特征以及当前的研究现状;然后阐述了该类型双星的测光研究方法。在三颗样本星的观测与研究中,取得以下研究成果。 1.利用云南天文台60cm望远镜对GSC 0763-0572进行三天的观测,首次获得V RI三个波段完整的光变曲线。结合文献中以及观测中获得的所有极小时刻,我们发现该双星系统轨道周期以dP/dt = +5.81(33) × 10−7天/年的速率增长。使用2003版W-D测光解轨程序,对V RI光变曲线进行分析,确认GSC 0763-0572是一颗小质量比q = 0.2330、相接度为f = 31.0%的A次型相接双星;进一步估算其子星质量分别为:M1 = 1.23M⊙和M2 = 0.29M⊙。GSC 0763-0572可能处于热弛豫震荡理论预言的膨胀演化阶段,最后可能演化为快速自转的单星。 2.2004年11月和2011年09月使用兴隆85cm望远镜先后对CW Cas观测两次,其中2004年的V 波段光变曲线表现出较为明显O’Connell效应,2011年的BVRI光变曲线几乎对称。对比不同观测时间的V 波段光变曲线,发现其存在变化,因此推测CW Cas表面可能存在黑子活动。在W-D解轨过程中,我们使用黑子模型获得测光参数。同时结合前人所有CCD极小时刻,对其轨道周期进行分析,发现其轨道周期除了包含长期减小(dP/dt = −1.15 × 10−7天/年)成分之外,还存在周期性(P3 = 45.95年,A3 = 0.0069天) 振荡。轨道周期的长期减小可能是由于从大质量星到小质量星的物质转移引起的,同时判定磁星风引起的角动量损失造成物质转移时标和热时标存在差异。系统轨道周期的周期振荡不能用Applegate磁活动周进行解释,最终认为是第三天体的光时轨道效应引起的。 3.同样使用2003版W-D测光解轨程序,对云南天文台1m望远镜获得的VRI三色测光曲线进行分析,确认V524 Mon为质量比q = 2.099,相接度f = 7.7%的W次 型相接双星。依据所有的光极小时刻,对轨道周期分析:系统的长期减小同样是由于大质量星到小质量星物质转移引起的,而周期变化可以解释为第三天体光时轨道效应。V524 Mon的临界结构与轨道周期的长期减小说明它可能是一颗新形成的相接双星系统。
Other AbstractThe structures of G-type components in solar-like binaries are the same as the sun’s. But, because of the faster rotation and the deeper convection, they show much more stronger sunlike activities, i.e., dark-spots and flares. In the first section of the present paper, the definition, observational characters, research status of contact binary are introduced. Later, some methods about photometric study of binary are simply illustrated. In the second section, according to the observation and study on three G-type solar-like contact binaries, some results are following as: 1. Using the 60-cm telescope at Yunnan Astronomical Observatory, it is the first time to obtain the complete V RI bands light curves for GSC 0763-0572,which were carried out for three nights. Based on all available times of light minimum, we found that the orbital period is undergoing a continuous increase at rate of dP/dt = +5.81(33) × 10−7days year−1. We analyzed the V RI light curves by using the Wilson-Devinney code, it is confirmed that GSC 0763-0572 is A-subtype contact binary with the mass ration of q = 0.2330, the degree of contact factor of f =31.0%. Meanwhile, we estimated that M1 = 1.23M⊙, M2 =0.29M⊙. It is inferred that GSC 0763-0572 may presently be in an expanding state of thermal relaxation oscillation, finally evolve into a rapid-rotating single star. 2. CCD photometric light curves of W UMa-type binary system CW Cas in 2004 and 2011 are obtained with the 85-cm telescope at Xinglong Station of National Astronomical Observatory. It was found that the V band light curve shows O’Connell effect in 2004, while BV RI light curves in 2011 are nearly symmetric. Compared with light curves in different observing seasons, the variation indicates that there are dark-spot activities on the surface of the components. With spot models of the 2003 version of the Wilson-Devinney code, we get photometric solutions. Based on all available photoelectric and CCD light minimum, we analyzed the change of orbital period. The period of the system shows a cyclic period change (P3 = 45.95years, A3 = 0.0069days) superimposed on the continual decrease (dP/dt = −1.15 × 10−7days year−1). The long-term period decrease can be explained by mass transfer from the more massive one to the less one or an enhanced stellar wind and angular momentum loss(AML). The Applegate mechanism probably can not describe the cyclic period change, which change was explained as the light-travel time effect of the presence of a tertiary companion. 3. With the 1-m telescope at Yunnan Astronomical Observatory, we have analyzed V RI light curves of V524 Mon with the 2003 version of the Wilson Devinney code. We confirm that V524 Mon is a shallow W-type contact binary system with a mass ratio of q = 2.099 and a degree of contact factor of f = 7.7%. Based on the new eight times of light minimum and those published by previous investigators, we find that the orbital period of the binary shows a long-term decrease while it undergoes a cyclic oscillation. The long-term period decrease can be explained by mass transfer from the more massive one to the less one. The cyclic change explained as the light-travel time effect reveals the presence of a tertiary companion. The marginal contact configuration and the continuous period decrease, both suggest that it may be a newly formed contact binary.
Subject Area天文学
Language中文
Document Type学位论文
Identifierhttp://ir.ynao.ac.cn/handle/114a53/5978
Collection双星与变星研究组
Recommended Citation
GB/T 7714
王晶晶. 类太阳G型相接双星的观测与研究[D]. 北京. 中国科学院研究生院(云南天文台),2012.
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