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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/86180


    Title: 低質量X光雙星X 1822-371軌道與自轉週期變化
    Authors: 林韋志;Lin, Wei-Chih
    Contributors: 物理學系
    Keywords: X 1822-371;X光雙星系統;脈衝星;掩食;低質量X光雙星;近密雙星;X 1822-371;eclipsing pulsar;X-ray binary;LMXB;partial eclipse;close binary
    Date: 2021-10-20
    Issue Date: 2021-12-07 12:13:37 (UTC+8)
    Publisher: 國立中央大學
    Abstract: X1822-371是由一顆中子星及其伴星所組成的低質量X光雙星系統,大量的物質被吸積在主星(即中子星)的表面並輻射出X光產生脈衝,且有一吸積盤圍繞在主星周圍,而巨大的吸積盤暈也使X1822-371有著偏食的現象。
    本篇研究利用XMM-Newton在2001年以及2017年對X1822-371的觀測資料做分析,了解此雙星系統在這二筆觀測時間中的掩食時間,接著結合前人之研究,總計長達38年的觀測紀錄來做分析。運用O-C分析所有觀測到的掩食時間更新X1822-371之二階星歷表,其軌道週期變化率p ?_orb=1.452(44)×?10?^(-10) s/s。更新後的p ?_orb值與以往相比有變小的趨勢,我們接著探討三階星歷表的可能性,但以F檢驗後的結果顯示以目前的觀測結果可能尚不足以證明更高階的軌道週期變化率之存在。我們接著利用X1822-371的脈衝時間來做分析,從脈衝除了可以獲得中子星的自轉週期外,也可獲得某些軌道參數,並與偏食所得值結果做比較。最終我們得到其自轉週期可以P_s (t)=0.5933348(38)s-2.6265(88)×?10?^(-12)×(t-MJD 50000)×86400來表示。而我們也得到二筆觀測內的T_(π?2),且同樣以O-C分析,發現T_(π?2)與掩食時間有著84秒左右的時間差,而這樣的時間差異可能與吸積盤暈的不對稱性有關。
    最後我將整理以上的結果來推估X1822-371的質量變化,與前人所研究之雙星系統的標準模型比較,X1822-371的軌道變化明顯表示出其系統的角動量變化與一般雙星系統的推論不同,部分的軌道變化可能與系統的質量流失有關。
    ;X 1822-371 is a neutron star low mass X-ray binary system with accretion disk corona exhibiting partial eclipses and pulsations. We updated the orbital ephemeris by combining the eclipsing times from historical records and from analyzing the eclipsing profiles detected by XMM-Newton in 2001 and 2017, with total time span of 38 years.
    In this thesis, a quadratic model fitted to the residuals using the O-C method yielded an orbital period derivative of ?p ?_orb=1.452(44)×10?^(-10) s/s , consistent but a little smaller than previous records. We attempted to find the possible second order orbital derivative (p ?_orb) by fitting the O-C residuals with a cubic model but found less confidence level. It is possible that p ?_orb and the higher order orbital derivatives still cannot be significantly detected with these 38-year data. Moreover we use pulsar timing to obtain the pulse periods and T_(π?2) of X 1822-371 of XMM-Newton observations in 2001 and 2017. The detected pulse periods show that the neutron star in X 1822-371 is continuously spun-up with a rate of P ?_s=(-2.6265±0.0088)×?10?^(-12) s s^(-1). And the detected T_(π?2) values are systematical earlier than the corresponding eclipse times by 84 seconds, this deviation is probably caused by the asymmetric accretion disc corona.
    Lastly, the detected orbital period was compared with the normal model by predecessor. It shows that the most orbital period changes were caused by the mass loss from the binary system, which was different from the normal model of X-ray binary.
    Appears in Collections:[物理研究所] 博碩士論文

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