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題 名 | 長期監測低質量X-Ray雙星4U 1820-30之軌道週期演化及運行機制=The Long Term Monitoring of Orbital Modulation for Low Mass X-Ray Binary 4U 1820-30 |
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作 者 | 楊盛智; 周翊; | 書刊名 | 臺北天文館學報 |
卷 期 | 2 民93.12 |
頁 次 | 頁50-61 |
分類號 | 323.84 |
關鍵詞 | 低質量X射線雙星; 階級式的三星系統; Low mass X-ray binary; Hierarchical triple system; Superhump; |
語 文 | 中文(Chinese) |
中文摘要 | 本篇使用1998-2002年RXTE(X-ray波段望遠鏡)長時間之監測的觀測數據,針對座落於球狀星團NGC 6624中心附近的低質量X-ray雙星(low mass X-ray binary) 4U 1820-30,之軌道光變加以分析,並尋找可能存在的運行機制。在1998-1999年的數據中,我們發現明顯的相位偏移(phase shift = -0.20 ~ -0.31)及相位跳動( phase jitter = 0.034 ) 結合前人自1976年以來觀測的結果,我們發現這個系統的軌道週期變化有明顯的二次微分項( ),並從三次擬合的結果得出 = (1.87±0.96) x 10-13 yr,由於這個系統的軌道週期有二次微分項的,以致前人可能低估了4U 1820-30的軌道變化。此外,我們應用一維的CLEAN演算法(one- dimensional CLEAN algorithm),來尋找可能因階級式三星系統或吸積盤進動造成在傅氏空間(Fourier space)中的差拍頻率的現象,但是在RXTE 1998-2000年的觀測資料中,我們並未發現這個現象。 |
英文摘要 | We report our analysis results of the orbital modulation for the ultra-compact low mass X-ray binary 4U 1820-30 in globular cluster NGC 6624 monitored by the Rossi X-ray Timing Explorer (RXTE) from 1998 to 2002. Clear phase drift from -0.20 to -031 as well as phase jitter of 0.034 are detected during the 1998-2000 observation period. Combined with the observation results since 1976, the orbital phase evolution is in fact better described as a cubic function rather than the quadratic model proposed by the historical reports. The cubic fitting yields the first discovered = (1.87±0.96) x 10-13 per year. We conclude that the previous period derivatives were probably underestimated due to the significant . On the other hand, the CLEAN algorithm was also applied to search the possible side bands made by a hierarchical third star (triple model) or the tidally driven modulations of the accretion disk (superhump). However, no significant (2σ upper limit) sideband was detected in our data sets. |
本系統中英文摘要資訊取自各篇刊載內容。