论文标题
热门科里诺化学多样性：神话还是现实？
Hot Corinos Chemical Diversity: Myth or Reality?
论文作者
论文摘要
经过将近20年的狩猎，只有大约十二个热的科里诺斯，富含星际复合物有机分子（ICOM）的热区域是已知的。其中许多是二元系统，两个组件显示出截然不同的分子光谱。出现了两个明显的问题。为什么热的科里诺斯很难找到，为什么它们的二元组件在化学上看起来有所不同？两个问题的答案可能是隐藏分子线的高尘埃不透明度。为了检验这一假设，我们使用非常大的阵列干涉仪观察到甲醇线在厘米波长时可忽略不计。我们针对NGC 1333 IRAS 4A二元系统，在毫米波长下观察到两个组件之一4A1中的一个4A1中的一个频谱被剥夺了ICOMS线，而另一个组件4A2则非常丰富ICOM。我们发现厘米甲醇线类似地向4A1和4A2亮。 Their non-LTE analysis indicates gas density and temperature ($\geq2\times10^6$ cm$^{-3}$ and 100--190 K), methanol column density ($\sim10^{19}$ cm$^{-2}$) and extent ($\sim$35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos.此外，与以前的甲醇线毫米观测值的比较使我们能够分别估计4A1和4A2前面的灰尘的光学深度。所获得的值解释了在毫米波长下对4A1的ICOM线发射的不存在，并表明对4A2的丰度被$ \ sim $ 30 \％低估了。因此，厘米的观察对于正确研究热的科里诺群岛，它们的人口普查和它们的分子丰度至关重要。
After almost 20 years of hunting, only about a dozen hot corinos, hot regions enriched in interstellar complex organic molecules (iCOMs), are known. Of them, many are binary systems with the two components showing drastically different molecular spectra. Two obvious questions arise. Why are hot corinos so difficult to find and why do their binary components seem chemically different? The answer to both questions could be a high dust opacity that would hide the molecular lines. To test this hypothesis, we observed methanol lines at centimeter wavelengths, where dust opacity is negligible, using the Very Large Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which one of the two components, 4A1, has a spectrum deprived of iCOMs lines when observed at millimeter wavelengths, while the other component, 4A2, is very rich in iCOMs. We found that centimeter methanol lines are similarly bright toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and temperature ($\geq2\times10^6$ cm$^{-3}$ and 100--190 K), methanol column density ($\sim10^{19}$ cm$^{-2}$) and extent ($\sim$35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison with previous methanol line millimeter observations allows us to estimate the optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained values explain the absence of iCOMs line emission toward 4A1 at millimeter wavelengths and indicate that the abundances toward 4A2 are underestimated by $\sim$30\%. Therefore, centimeter observations are crucial for the correct study of hot corinos, their census, and their molecular abundances.
