RS CVn型密近双星AR Lac和RT Lac的轨道周期分析
发布时间：2018-09-07 08:23
【摘要】：RS CVn型双星是一类磁活动较强的食双星系统，它们不仅能够发射很强的Hα、CaII的H和K谱线，并且还表现出大面积的黑子活动、耀斑、星风损失、X射线发射等许多类似太阳的磁活动现象。由于这些磁活动对RS CVn型双星的轨道周期变化有很大的影响，引起许多天文工作者的极大兴趣。 本文先介绍了密近双星系统的轨道周期变化的基本研究方法。然后对蝎虎座中的两个RS Cvn型密近双星样本AR Lac和RT Lac的轨道周期变化进行分析，得到以下的研究结果： 1.首先从文献和数据库搜集了AR Lac大量的光极小时刻，，利用新历元进行计算AR Lac光极小时刻的理论值，求出O C值,然后用加权最小二乘法对系统的O C曲线进行拟合，最后对双星系统AR Lac的轨道周期进行分析。发现双星系统AR Lac的轨道周期显示出一个周期为50.93年、振幅为0.0362天的正弦式的周期性变化，在其上还叠加一个长期的变化率dP/d t=-(2.128±0.060)×10-9天/天的非周期性变化。AR Lac的轨道周期的周期性变化可能是次星的周期性磁活动引起了，轨道周期的非周期性长期减小可能由次星强的星风磁滞引起的。 2.对RS CVn型双星RT Lac的轨道周期进行了分析，我们得到一个调制周期为Pm od=278.04yr，而且还以一个周期变化率为dP/dt=(4.81±7.33)×109天/天的长期减少。278.04年的长周期变化可能是由双星系统的磁活动引起的，而不是第三天体的光时轨道效应的影响。由于RT Lac是典型的分离双星，两子星间的物质交流不能解释它的轨道周期的长期减少。但星风磁滞理论计算出的非周期性变化值与观测值有几个数量级的差别，所以也不能用磁滞来解释。
[Abstract]:RS-CVn binaries are a kind of eclipsing binary systems with strong magnetic activity. They can not only emit strong H_ a, Ca_ II H and K lines, but also exhibit many solar-like magnetic activities, such as large-area black activity, flares, stellar wind losses, X-ray emission and so on. The influence has aroused great interest of many astronomers.
In this paper, the basic research methods of orbital periodic variations of close binary systems are introduced. Then the orbital periodic variations of two RS Cvn close binary samples, AR Lac and RT Lac, in the constellation Scorpio Tiger, are analyzed. The following results are obtained:
1. Firstly, a large number of AR Lac optical hourly moments are collected from literature and databases, and the theoretical values of AR Lac optical hourly moments are calculated by using new epochs. Then the O C curves of the system are fitted by the weighted least square method. Finally, the orbital period of the binary system AR Lac is analyzed. The period shows a sinusoidal periodic variation with a period of 50.93 years and an amplitude of 0.0362 days. A long-term variation rate dP/d t=-(2.128 +0.060)*10-9 days/day is superimposed on it. The periodic variation of the orbital period of AR Lac may be caused by the periodic magnetic activity of the sub-stars and the non-periodic length of the orbital period. The decrease of the period may be caused by the strong star wind hysteresis.
2. Analyzing the orbital period of the RS CVn binary RT Lac, we find that a modulation period is Pm od=278.04yr, and a long-term decrease of dP/dt=(4.81 +7.33)*109 days/day with a period change rate. The long-period change of 278.04 may be caused by the magnetic activity of the binary system, not by the optical-time orbital effect of the third celestial body. Because RT Lac is a typical separated binary, the mass exchange between the two stars cannot explain the long-term decrease of its orbital period, but the non-periodic variation calculated by the stellar wind hysteresis theory differs several orders of magnitude from the observed value, so it can not be explained by the hysteresis.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P144
本文编号：2227730
[Abstract]:RS-CVn binaries are a kind of eclipsing binary systems with strong magnetic activity. They can not only emit strong H_ a, Ca_ II H and K lines, but also exhibit many solar-like magnetic activities, such as large-area black activity, flares, stellar wind losses, X-ray emission and so on. The influence has aroused great interest of many astronomers.
In this paper, the basic research methods of orbital periodic variations of close binary systems are introduced. Then the orbital periodic variations of two RS Cvn close binary samples, AR Lac and RT Lac, in the constellation Scorpio Tiger, are analyzed. The following results are obtained:
1. Firstly, a large number of AR Lac optical hourly moments are collected from literature and databases, and the theoretical values of AR Lac optical hourly moments are calculated by using new epochs. Then the O C curves of the system are fitted by the weighted least square method. Finally, the orbital period of the binary system AR Lac is analyzed. The period shows a sinusoidal periodic variation with a period of 50.93 years and an amplitude of 0.0362 days. A long-term variation rate dP/d t=-(2.128 +0.060)*10-9 days/day is superimposed on it. The periodic variation of the orbital period of AR Lac may be caused by the periodic magnetic activity of the sub-stars and the non-periodic length of the orbital period. The decrease of the period may be caused by the strong star wind hysteresis.
2. Analyzing the orbital period of the RS CVn binary RT Lac, we find that a modulation period is Pm od=278.04yr, and a long-term decrease of dP/dt=(4.81 +7.33)*109 days/day with a period change rate. The long-period change of 278.04 may be caused by the magnetic activity of the binary system, not by the optical-time orbital effect of the third celestial body. Because RT Lac is a typical separated binary, the mass exchange between the two stars cannot explain the long-term decrease of its orbital period, but the non-periodic variation calculated by the stellar wind hysteresis theory differs several orders of magnitude from the observed value, so it can not be explained by the hysteresis.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P144
【参考文献】
相关期刊论文 前1条
1 杨远贵;;如何计算密近双星中光时轨道效应[J];中国科学(G辑:物理学 力学 天文学);2009年04期
本文编号：2227730
本文链接：https://www.wllwen.com/kejilunwen/tianwen/2227730.html
