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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/5998


    Title: 系外行星系統所造成的微重力透鏡效應;Gravitational Microlensing by Exoplanetary Systems
    Authors: 侯淑慧;Shu-Huei Hou
    Contributors: 天文研究所
    Keywords: 微重力透鏡;系外行星系統;exoplanetary system;gravitational microlensing
    Date: 2003-05-30
    Issue Date: 2009-09-22 10:11:39 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 人類自從1993年朝著大麥哲倫雲的方向,看到了第一次微重力透鏡現象(Alcock, et al. 1993 )後,許多關於微重力透鏡的計畫正如火如荼的展開,一直至今,已經有超過500件的微重力透鏡效應被發現(Wambsganss 2001)。而其中已經有6個微重力透鏡效應,被懷疑是由似行星天體所造成的微重力透鏡效應之光變曲線。 我們模擬透鏡的部分為各類假設的系外行星系統下,其所造成的微重力透鏡效應會有哪些不同的變化,討論其焦散曲線與光變曲線之變化情形。最後,我們將模擬的光變曲線與一真實觀測資料OGLE-2002-BLG-055對照比較。模擬結果發現,隨著行星數目的增加,則其所造成的焦散曲線之結構範圍亦增多,亦即相對而言,則越容易有微重力透鏡現象之發生。且當行星軌道半徑的張角趨近於愛因斯坦角時(θP →θE),則其所造成的焦散曲線結構所圍之面積也愈大。對於光變曲線之模擬,我們發現光變曲線之主高峰點發生在系外行星系統之主星與光源 距離為最接近時。當光源經過焦散點時,會造成光變曲線上異常突起之現象,而異常突起的次數取決於光源掃過焦散點之次數。也因為如此,所以若在真實觀測時,我們會建議每次觀測之時間間隔要短,但總觀測時間需長,如此才不至於錯失一些透露著系外行星資訊的珍貴訊息。 未來我們將嘗試藉由一真實觀測之光變曲線,反推其透鏡系統是如何組成、及與光源相關的參數之確定,以期有效率的模擬、預測其系外行星系統的各個參數。另外,我們試著從動力學的計算,來合理的考慮模擬的系外行星系統之各個參數的值,這也將列入我們未來工作的重點。 Microlensing, which occurs when a foreground object moves between an observer and a luminous background object, was proposed as a method to detect Galactic dark matter by Paczyński (1986) .When a microlensing event occurs, the luminous background object would be brighter by a great factor. This brightness amplification factor depends on the mass distribution of the foreground object and the relative position of the luminous background object. In this paper we determine the light curves of microlensing events for different planetary systems as foreground objects. We found that the light curve has many spikes during a microlensing event, and these structures depend on the number of planets, the periods of planets, etc. Therefore, our results should be useful for the future detections of multiple planetary systems.
    Appears in Collections:[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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