EAST Network是一個全球性的觀測網。建立全球觀測網的目的在於可以解決因地球自轉所造成觀測的不連續，因為不連續的觀測往往在數據分析上造成許多的假訊號。在論文的前半段，我的工作重心放在建立快速搜尋變星的方法還有變星光度曲線的分析上。在任意星場中，運用Ensemble Photometry (Honeycutt 1992) 的概念搜尋可疑的變星。這個方法可以自動且快速的過濾出可疑的目標，有助於我們在觀測星團時快速的找到變星。在進行相對測光的過程中，我們建立一個改良的方法來修正參考星，並且成功的降低了光度曲線的波動，使之更為平滑。在論文的後半段，我的重心放在變星震盪頻率的分析上。我們使用程式PERIOD04 (Lenz & Breger 2004) 來做為分析的工具。分析的目標則為兩顆雙星：HD 163032和HD 6859。HD 163032為EAST在2007年5月所發現的一顆變星 (王立涵 2007)，在此之前並無任何文獻記載有關其光度變化的資訊。HD 6859則是一顆已知δ Scuti型態的變星。經過頻率分析後，我們發現HD 163032的主要震盪頻率符合一顆δ Scuti型態的變星，若能確定其光譜類型，將有助於我們進一步判斷光變的型態。然而在觀測上，這兩顆雙星的duty-cycle都非常小 (HD 163032為0.18；HD 6859為0.02)，所以頻率分析結果的信任程度不是很高。另外存在的問題是，不同天之間光度曲線的零點飄移很嚴重，並造成一極低頻的訊號，這也影響我們分析結果的準確性。我們懷疑此為不同星體其不同天之間系統變化上的差異，而非真正的訊號。觀測時間上過小的duty-cycle還有光度曲線零點飄移的問題都希望能在將來EAST進行長時間的連續觀測下獲得解決。

EAST Network is a globally observational network. It is expected to solve the problem of time gaps appeared in a long term observation caused by the rotation of the earth. The time string data with gaps may result in fake signals. In the beginning of thesis, we present the works on the search of variable stars and light curve analysis. We use ensemble photometry (Honeycutt 1992) to search the suspects of variable in a group of stars automatically. The method will be helpful in searching the variables in star clusters. In the procedure of differential photometry, we develop an improved technique to modify our reference star. We not only smooth the reference but also preserve its spectral feature. The fluctuations of light curves are reduced successfully. Next, we use the program PERIOD04 (Lenz & Breger 2004) to analyze the multi-periodic properties of our targets. The targets are two double stars HD163032 and HD 6859. HD 163032 is a new variable star discovered by EAST on May 2007 (Li-Han, Wang 2007). There is no measurement recorded about its variability before. HD 6859 is a known δ scuti variable. After period analysis, we found that the dominant frequencies of HD 163032 correspond to a typical δ scuti variable. If we can confirm its spectral type, we may probably infer the variable type of HD 163032. For both double stars, the observational duty cycle is low (0.18 for HD 163032; 0.02 for HD 6859), so the extracted frequencies are not convincing enough. Furthermore, the drift of zero-points in light curves from different days seems to affect the results of our analysis. We think it may be caused by the differences of systematic variation between different days. We hope that a continued observation of different sites in the future will improve the quality of our data.

[1] Breger, M. 2007, CoAst, 150, 25
[2] Honeycutt, R. K. 1992, PASP, 104, 435
[3] Li-Han, Wang 2007, Data Reduction of EAST Network and Variables
Research (Master thesis)
[4] Lenz, P., Breger, M. 2004, IAUS, 224, 786
[5] Breger, M. et al. 1999, A&A, 349, 225
[6] Kharchenko 2001, All-sky Compiled Catalogue of 2.5 million stars
[7] Dommanget+ 2002, Catalog of Components of Double & Multiple stars
[8] Rodr´ıguez, E. et al. 2004, A&AS, 144, 469