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題 名 | The Photometry, Kinematics and Dynamics of Young Open Cluster NGC 6910=年輕疏散星團NGC 6910之光度、運動與動力 |
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作 者 | 吳志剛; 傅學海; | 書刊名 | 臺北天文館學報 |
卷 期 | 2 民93.12 |
頁 次 | 頁41-49 |
分類號 | 323.84 |
關鍵詞 | 疏散星團; 恆星計數; 金氏模式; Open cluster; Star count; King model; |
語 文 | 英文(English) |
中文摘要 | 本研究針對年輕疏散星團NGC 6910,以中央大學鹿林前山天文臺一米望遠鏡進行光度觀測,獲得星團光度、星際吸收與紅化、距離與年齡等參數。以美國海軍天文臺星表B1.0(USNO-B1.0)之數據,進行恆星計數統計,以及星團運動與動力方面的分析,以推算星團的半徑、密集度等參數。 在對NGC6910中心區域進行CCD Johnson UBV三波段光度觀測,UBV三波段之光度誤差分別為0.056, 0.028 與 0.021星等,紅化為E(B-V) = 1.11±0.16。將修正紅化後的星團星色─星等圖(CMD)與恆星演化等時模型〈isochrones〉擬合的結果顯示,NGC 6910的年齡約為3.98百萬年至一千萬年之間,距離模式為10.88。 根據USNO-B1.0 中POSS-I 103a-O blue sensitive plates 測定星等,星團1°×1°範圍內的座標作為資料庫,進行恆星計數統計分析。結果顯示NGC 6910的表面恆星數量密度分佈符合金氏模式(King 1962),當距離為1500pc時,核心半徑(rc)2.48 pc,潮汐半徑(rt)26.13 pc, k=12.50 stars/pc2。Oort常數採用A = 14.4±0.8 km s-1 kpc-1 、B = -12.4±0.6 km s-1 kpc--1(Feast and Whitelock 1997),則星團總質量約為6400 M☉。 |
英文摘要 | Based on the Johnson UBV CCD photometry of a young open cluster NGC 6910 with 1.0-m telescope at Lulin Observatory of National Central University, the magnitude, extinction, reddening, distance and age of clusters are derived. The USNO-B1.0 catalogue is used for star counting method of King model. In the photometric calibration, it shows the standard errors 0.056 mag in U, 0.028 mag in B and 0.021 mag in V. The reddening E(B-V) is determined to be 1.11±0.16 mag. The age of NGC 6910 is estimated, using well isochrones fit, to be 4~10 Myrs and its distance modulus is 10.88. The magnitudes and coordinates in the USNO-B1.0 catalogue are derived from the POSS-I 103a-O blue sensitive plates. The analysis of the star counting is based on the images within the area 1°×1° centered at the cluster. The results show that the radial distribution of the stellar number density for NGC 6910 is consistent with the King’s model. The best fit gives core radius (rc) 2.48 pc, tidal radius (rt) 26.13 pc and k=12.50 stars/pc2. By adopting the Oort’s constants A = 14.4±0.8 km s-1 kpc-1, B = -12.4±0.6 km s-1 kpc-1 (Feast and Whitelock 1997), the mass of NGC 6910 is estimated to be about 6400 M☉. |
本系統中英文摘要資訊取自各篇刊載內容。