论文标题
L1544中的水和甲醇冰
Water and Methanol Ice in L1544
论文作者
论文摘要
甲醇和复杂的有机分子已经在冷的无星核中发现，由于没有热源，因此标准的热身场景无法正常工作。最近的化学模型将甲醇和大型有机物的存在归因于有效的化学解吸和一类中性中性反应，这些反应在气相的低温下快速进行。该型号要求在冷云芯中CO冷冻区域边缘的甲醇冰中高丰富。我们以3 $ $ m的恒星核L1544后面的3 $ m $ m的核心芯L1544后面的3局恒星进行了中等分辨率光谱，以限制甲醇冰的丰度并将其与模型预测进行比较。其中一颗田间恒星显示水冰的甲醇冰含量为11％。这高于先前在冷云核中发现的典型甲醇丰度（4％），但比预测的小4.5倍。观察结果与模型计算之间存在分歧的原因尚未理解。
Methanol and complex organic molecules have been found in cold starless cores, where a standard warm-up scenario would not work because of the absence of heat sources. A recent chemical model attributed the presence of methanol and large organics to the efficient chemical desorption and a class of neutral-neutral reactions that proceed fast at low temperatures in the gas phase. The model calls for a high abundance of methanol ice at the edge of the CO freeze-out zone in cold cloud cores. We performed medium resolution spectroscopy toward 3 field stars behind the starless core L1544 at 3 $μ$m to constrain the methanol ice abundance and compare it with the model predictions. One of the field stars shows a methanol-ice abundance of 11% with respect to water ice. This is higher than the typical methanol abundance previously found in cold cloud cores (4%), but is 4.5 times smaller than predicted. The reason for the disagreement between the observations and the model calculations is not yet understood.
