论文标题
高质量恒星形成区域中复杂有机分子的进化研究
Evolutionary study of complex organic molecules in high-mass star-forming regions
论文作者
论文摘要
我们研究了四个复杂的有机分子（COM），甲基甲酸甲酯（$ ch_3ocho $），二甲基乙醚（$ ch_3och_3 $），甲酰胺（$ nh_2cho $）和氰化乙基（$ c_2h_5cn $），供39个高级射量的大型射击区域的大量样本，以供应不同的是不同的供应。我们旨在确定分子之间的潜在相关性，并通过恒星形成过程追踪其进化序列。我们分析了IRAM-30M望远镜在3、2和0.9 mm处获得的光谱。我们通过拟合分子线来得出每个物种的主要物理参数。我们比较了它们并评估了它们的演变，还考虑了其他几个星际环境。我们报告了20个来源的检测，揭示了对色谱柱密度的明显吸收作用。 Derived abundances are ~$10^{-10}-10^{-7}$ for $CH_3OCHO$ and $CH_3OCH_3$, ~$10^{-12}-10^{-10}$ for $NH_2CHO$, and ~$10^{-11}-10^{-9}$ for $C_2H_5CN$. $ CH_3OCHO $，$ CH_3OCH_3 $和$ C_2H_5CN $的丰富性在〜4个数量级上非常强烈（r> 0.92）。 $ CH_3OCHO $和$ CH_3OCH_3 $在大多数参数中显示出最强的相关性，并且对于多种来源的亮度〜9个数量级，几乎恒定的比率（〜1）的比率（〜1）：多种来源：预生效的核心与进化的核心与进化的核心，低至高质量的对象，震惊，震动，震惊，银色的云和comets和Comets和Comets和Comets和Comets。这表明COMS化学可能是早期开发的，然后通过进化的阶段保存。此外，分子丰度显然随进化而增加。我们认为$ ch_3ocho $和$ ch_3och_3 $最有可能是化学链接的：他们可以共享一个共同的前体，或者是另一个共同的前体。我们为所有COM提出了一个一般方案，涉及在恒星形成的寒冷，最早的阶段形成，并随着不断发展的核心的进行性加热而增加的解吸。
We have studied four complex organic molecules (COMs), methyl formate ($CH_3OCHO$), dimethyl ether ($CH_3OCH_3$), formamide ($NH_2CHO$), and ethyl cyanide ($C_2H_5CN$), towards a large sample of 39 high-mass star-forming regions representing different evolutionary stages, from early to evolved phases. We aim to identify potential correlations between the molecules and to trace their evolutionary sequence through the star formation process. We analysed spectra obtained at 3, 2, and 0.9 mm with the IRAM-30m telescope. We derived the main physical parameters for each species by fitting the molecular lines. We compared them and evaluated their evolution, also taking several other interstellar environments into account. We report detections in 20 sources, revealing a clear dust absorption effect on column densities. Derived abundances are ~$10^{-10}-10^{-7}$ for $CH_3OCHO$ and $CH_3OCH_3$, ~$10^{-12}-10^{-10}$ for $NH_2CHO$, and ~$10^{-11}-10^{-9}$ for $C_2H_5CN$. The abundances of $CH_3OCHO$, $CH_3OCH_3$, and $C_2H_5CN$ are very strongly correlated (r>0.92) across ~4 orders of magnitude. $CH_3OCHO$ and $CH_3OCH_3$ show the strongest correlations in most parameters, and a nearly constant ratio (~1) over a remarkable ~9 orders of magnitude in luminosity for a wide variety of sources: pre-stellar to evolved cores, low- to high-mass objects, shocks, Galactic clouds, and comets. This indicates that COMs chemistry is likely early developed and then preserved through evolved phases. Moreover, the molecular abundances clearly increase with evolution. We consider $CH_3OCHO$ and $CH_3OCH_3$ to be most likely chemically linked: they could e.g. share a common precursor, or be formed one from the other. We propose a general scenario for all COMs, involving a formation in the cold, earliest phases of star formation and a following increasing desorption with the progressive heating of the evolving core.
