【摘要】：RS CVn型雙星是一類磁活動(dòng)較強(qiáng)的食雙星系統(tǒng)，它們不僅能夠發(fā)射很強(qiáng)的Hα、CaII的H和K譜線，并且還表現(xiàn)出大面積的黑子活動(dòng)、耀斑、星風(fēng)損失、X射線發(fā)射等許多類似太陽(yáng)的磁活動(dòng)現(xiàn)象。由于這些磁活動(dòng)對(duì)RS CVn型雙星的軌道周期變化有很大的影響，引起許多天文工作者的極大興趣。 本文先介紹了密近雙星系統(tǒng)的軌道周期變化的基本研究方法。然后對(duì)蝎虎座中的兩個(gè)RS Cvn型密近雙星樣本AR Lac和RT Lac的軌道周期變化進(jìn)行分析，得到以下的研究結(jié)果： 1.首先從文獻(xiàn)和數(shù)據(jù)庫(kù)搜集了AR Lac大量的光極小時(shí)刻，，利用新歷元進(jìn)行計(jì)算AR Lac光極小時(shí)刻的理論值，求出O C值,然后用加權(quán)最小二乘法對(duì)系統(tǒng)的O C曲線進(jìn)行擬合，最后對(duì)雙星系統(tǒng)AR Lac的軌道周期進(jìn)行分析。發(fā)現(xiàn)雙星系統(tǒng)AR Lac的軌道周期顯示出一個(gè)周期為50.93年、振幅為0.0362天的正弦式的周期性變化，在其上還疊加一個(gè)長(zhǎng)期的變化率dP/d t=-(2.128±0.060)×10-9天/天的非周期性變化。AR Lac的軌道周期的周期性變化可能是次星的周期性磁活動(dòng)引起了，軌道周期的非周期性長(zhǎng)期減小可能由次星強(qiáng)的星風(fēng)磁滯引起的。 2.對(duì)RS CVn型雙星RT Lac的軌道周期進(jìn)行了分析，我們得到一個(gè)調(diào)制周期為Pm od=278.04yr，而且還以一個(gè)周期變化率為dP/dt=(4.81±7.33)×109天/天的長(zhǎng)期減少。278.04年的長(zhǎng)周期變化可能是由雙星系統(tǒng)的磁活動(dòng)引起的，而不是第三天體的光時(shí)軌道效應(yīng)的影響。由于RT Lac是典型的分離雙星，兩子星間的物質(zhì)交流不能解釋它的軌道周期的長(zhǎng)期減少。但星風(fēng)磁滯理論計(jì)算出的非周期性變化值與觀測(cè)值有幾個(gè)數(shù)量級(jí)的差別，所以也不能用磁滯來(lái)解釋。
[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.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：P144

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 楊遠(yuǎn)貴;;如何計(jì)算密近雙星中光時(shí)軌道效應(yīng)[J];中國(guó)科學(xué)(G輯:物理學(xué) 力學(xué) 天文學(xué));2009年04期

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