搜尋太陽系外行星(extra-solar planet;exoplanet)是當今天文學家最重要的計畫之ㄧ;其中,當系外行星經過其主恆星碟面時,會造成光度略微下降,稱之為凌日現象(transit) 。本研究便是利用鹿林天文台SLT(Sne Little Telescope)望遠鏡來拍攝兩顆已知的系外行星HD 189733 b 和HD 209458 b在凌日時的影像。 我們得到約4000 張影像,再經過影像修正與資料分析後,我們作出凌日光變曲線圖、Bin圖及相位圖,並從中探討其特性。 經分析判斷後,HD 189733 看到一個剛開始發生和一個完整的凌日現象,分別由B濾鏡和 R 濾鏡所拍攝;而 HD 209458 則看到兩個剛開始發生,三個要結束的凌日現象,分別由B濾鏡、R 濾鏡和 Hα 濾鏡。 並由光變曲線,推得HD 189733 的基本參數,包括:行星半徑為 1.242個木星半徑、軌道傾角為88.94 度以及軌道半徑為 0.03115 天文單位。 Since 1995, more than 200 extra-solar planets have been found. Until today, astronomers still make efforts in searching extra-solar planets because it’s one of the most important projects in this century. During the crossing by the stellar disks (i.e., transits), the exoplanets will cause the brightness to decrease by a small amount. In the project, we have focused on the observations of two known transit exoplanets, HD 189733 b and HD 209458 b. The photometric observations were performed with the 40-cm SLT telescope on the Lulin Observatory. The results from the image procuring, data reduction and analysis are presented. We accrue and plot the light curve, bin and phase. We found out that HD 189733 has two transit ingresses with B, R band, and HD 209458 has two transit ingresses, two transit egresses with B, R, Hα band on phase. We figure out planetary parameters, RP is 1.242 RJ, inclination is 88.94° and orbital semi-major axis is 0.03115 AU by transit light curve.
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