發(fā)布時間：2018-02-16 09:20

  本文關(guān)鍵詞： W51 North 分子線 大質(zhì)量恒星　出處：《云南大學》2016年碩士論文　論文類型：學位論文

【摘要】：在本文中,我們報道了亞毫米波干涉陣(SMA)對大質(zhì)量恒星形成區(qū)W51North區(qū)域的觀測結(jié)果,得到了兩個邊帶的分子譜線,其頻率范圍分別是216.5 GHz到217.5 GHz(下邊帶)和226.5 GHz至228.5 GHz(上邊帶)�；谟^測數(shù)據(jù),我們運用XCLASS軟件證認了這些躍遷來自于17個分子品種(包括同位素分子),這些分子品種包括了含氧分子,含氮分子,含硫分子和含重氫分子。我們證認了13個丙酮分子((CH3)2CO)的躍遷,證認了W51 North是銀河系中第三個發(fā)現(xiàn)丙酮分子的天體。從分子氣體分布看,這些分子的分布在其峰值位置周圍呈現(xiàn)出比較致密的特征,而且它們峰值位置與連續(xù)譜峰值位置一致,含氧和含氮分子在分布上并沒有明顯差異。在局部熱動平衡的假設下,我們使用了XCLASS軟件估算了這些分子的柱密度和轉(zhuǎn)動溫度,結(jié)果表明,含氧分子的柱密度(4.3×1016到2.3×1018 cm-2)比含氮分子要高(2.8×1015到2.6×1016 cm-2)。所有分子的轉(zhuǎn)動溫度都在100—200 K的范圍內(nèi),這表明,這些分子起源于一個溫暖的天體物理環(huán)境。根據(jù)連續(xù)譜的信息,我們計算得到了H2的柱密度為6.4×1024cm-2,并計算了所有分子相對于H2的豐度。結(jié)果表明相比于含氮分子,含氧分子擁有較高的豐度。最后,基于這些分子的氣體分布、豐度和轉(zhuǎn)動溫度、我們推測這些來自W51 North的分子所產(chǎn)生的環(huán)境是一個氮和氧混合得很好的熱核。
[Abstract]:In this paper, we report the observation results of the large mass star formation region W51 North by submillimeter wave interference array (SMA). The molecular spectral lines of two sideband are obtained. Their frequency ranges are 216.5 GHz to 217.5 GHz (lower sideband) and 226.5 GHz to 228.5 GHz (upper sideband). We used the XCLASS software to identify that these transitions came from 17 molecular species (including isotopic molecules, including oxygen molecules, nitrogen molecules, We have identified the transition of 13 acetone molecules, Ch _ 3H _ 2CO) and that W51 North is the third object in the Milky way to find acetone molecules. The distribution of these molecules is dense around their peak position, and their peak position is consistent with the peak position of continuous spectrum. There is no significant difference in the distribution of oxygen and nitrogen molecules. Under the assumption of local thermodynamic equilibrium, We use XCLASS software to estimate the column density and rotation temperature of these molecules. The results show that the column densities of oxygen molecules are 4.3 脳 1016 to 2.3 脳 1018 cm-2) higher than that of nitrogen-containing molecules. The rotation temperatures of all molecules are in the range of 100-200K. These molecules originated in a warm astrophysical environment. Based on the information of the continuous spectra, we calculated the column density of H2 is 6.4 脳 1024cm-2, and calculated the abundance of all the molecules relative to H2. Finally, based on the gas distribution, abundance and rotation temperature of these molecules, we speculate that the environment produced by these molecules from W51 North is a hot nucleus with a good mixture of nitrogen and oxygen.
【學位授予單位】：云南大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：P144;P148
，

本文編號：1515182