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Title: | 多極瓣前行星狀星雲形成機制之觀測與模擬 Formation Mechanism of Multipolar Pre-planetary Nebulae: Observations and Simulations |
Authors: | Po-Sheng Huang 黃柏盛 |
Advisor: | 李景輝(Chin-Fei Lee) |
Keyword: | 恆星風,恆星噴流,恆星質量流失,前行星狀星雲,後漸近巨星分支,漸近巨星分支, Asymptotic giant branch stars,Pre-planetary nebulae,Stellar winds,Stellar mass loss,Post-asymptotic giant branch,Stellar jets, |
Publication Year : | 2020 |
Degree: | 博士 |
Abstract: | 近幾十年,隨著天文觀測技術的進步,前行星狀星雲的形成機制逐漸成為中低質量恆星在其晚期演化過程中的重要議題。其中,多極瓣的前行星狀星雲有著最為複雜的結構,也有多位學者提出理論模型尚>待證實。本文以此為題,探討在前行星狀星雲階段甚或上一階段的漸近巨星分支如何噴發出多方向性的高速物質。研究的方法包括(1)統合現有光學與電波天文學的觀測資料建構高速物質噴發的三維流體動力學模擬,以及(2)利用高角分辨率與速度解析度的阿塔卡瑪大型毫米及次毫米波陣列來探測多極化噴流的細微結構與速度分佈。研究結果也與現有的數個主流模型做比對,如:爆炸性彈狀模型與間歇性螺旋噴流模型。研究發現多向性彈狀噴發可以模擬多極瓣前行星狀星雲的形成,而觀測結果則顯示,某些較晚出現的多極瓣噴流則可能是間歇性螺旋噴發所形成的。而這兩種機制可能皆來自於雙星與吸>積盤的交互作用。 We present our recent works on the formation mechanism of multipolar pre-planetary nebulae (PPNs) and high-speed bullet ejections from an asymptotic giant branch (AGB) star. These works include 3D hydrodynamical simulations producing collimated outflows by multidirectional bullets and high-angular-resolution radio observations using Atacama Large Millimeter/submillimeter Array (ALMA). We compare our results with current competing models. One is an explosive bullet model. Another is a precessing collimated-fast-wind (CFW) model incorporating a time-dependent ejection velocity. We found that the multidirectional bullets can shape multipolar PPNs. In some cases, a binary companion might be needed to produce multidirectional bullets or the precessing CFW with time-dependent ejection velocity. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/66604 |
DOI: | 10.6342/NTU202000353 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 天文物理研究所 |
Files in This Item:
File | Size | Format | |
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ntu-109-1.pdf Restricted Access | 21.52 MB | Adobe PDF |
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