论文标题
星际谷物碰撞中的冰分子解吸
Icy molecule desorption in interstellar grain collisions
论文作者
论文摘要
在冷的无星和prestellar云芯中观察气态复合有机分子（COM）需要有效解除COM及其母体从星际晶粒上的冰盖地幔中的出现。使用简单的星体化学模型，我们研究了在两个大小垃圾箱（0.01和0.1微米）之间的斜碰撞中机械去除冰块是否会大大影响com的丰度。考虑了两个晶粒碰撞速度-10和50米，分别对应于型逼真的晶粒相对速度，分别是由双极扩散和湍流引起的。从较小的谷物中，假定碰撞分别以等于1/3和1冰盖的厚度去除球形盖。我们发现，湍流诱导的解吸可以将COM的气相丰度提升到几个数量级，从而在数量级内重现观察到的COM丰度。重要的是，长时间的高度尺度达到了高达1 Myr的高气气体丰度，并且甲醇冰的丰度相当低，这对于无星核很常见。这个简单的模型仅考虑两个晶粒尺寸垃圾箱和几个假设，展示了必须以更复杂的方法进行测试的概念。
Observations of gaseous complex organic molecules (COMs) in cold starless and prestellar cloud cores require efficient desorption of the COMs and their parent species from icy mantles on interstellar grains. With a simple astrochemical model, we investigate if mechanical removal of ice fragments in oblique collisions between grains in two size bins (0.01 and 0.1 micron) can substantially affect COM abundances. Two grain collision velocities were considered - 10 and 50 meters per second, corresponding to realistic grain relative speeds arising from ambipolar diffusion and turbulence, respectively. From the smaller grains, the collisions are assumed to remove a spherical cap with height equal to 1/3 and 1 ice mantle thickness, respectively. We find that the turbulence-induced desorption can elevate the gas-phase abundances of COMs by several orders of magnitude, reproducing observed COM abundances within an order of magnitude. Importantly, the high gaseous COM abundances are attained for long time-scales of up to 1 Myr and for a rather low methanol ice abundance, common for starless cores. The simple model, considering only two grain size bins and several assumptions, demonstrates a concept that must be tested with a more sophisticated approach.
