Glycolaldehyde, methyl formate and acetic acid adsorption and thermal desorption from interstellar ices
Glycolaldehyde, methyl formate and acetic acid adsorption and thermal desorption from interstellar ices
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DOI：
10.1093/mnras/stu2490
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发表时间：
2015-02-21
影响因子：
4.8
通讯作者：
Slater, Ben
中科院分区：
文献类型：
--
作者：
Burke, Daren J.;Puletti, Fabrizio;Slater, Ben
我们已经进行了详细的调查的吸附，解吸和热处理的天体生物学显着的异构体乙醇醛，乙酸和甲酸甲酯。在这里，我们提出了实验室红外和程序升温脱附（TPD）的研究结果，从模型星际冰吸附在碳质尘埃颗粒模拟表面的三种异构体。实验室红外数据表明，异构体可以清楚地区分其红外光谱的基础上，这对星际冰光谱的观测有影响。实验室TPD数据还表明，这三种异构体可以区分的基础上，他们的热脱附行为。特别是，TPD数据表明，异构体不能以同样的方式处理天体物理模型的解吸。乙醇醛和乙酸从以水为主的冰中的解吸非常相似，解吸主要由水冰决定。然而，甲酸甲酯也从冰的表面解吸，作为纯解吸特征，因此在比其他两种异构体更低的温度下解吸。这是更清楚地表明，模型的解吸对天体物理学的时间尺度对应的加热率的25和5 M-圆点星。对于一个25 M-圆点星星，我们的模型表明，甲酸甲酯的比例可以发现在气相中在较早的时间相比，乙醇醛和乙酸。这对这些分子的观察和检测具有影响，并可能解释为什么甲酸甲酯在比其他两种异构体更广泛的天体物理环境中被观察到。
We have undertaken a detailed investigation of the adsorption, desorption and thermal processing of the astrobiologically significant isomers glycolaldehyde, acetic acid and methyl formate. Here, we present the results of laboratory infrared and temperature programmed desorption (TPD) studies of the three isomers from model interstellar ices adsorbed on a carbonaceous dust grain analogue surface. Laboratory infrared data show that the isomers can be clearly distinguished on the basis of their infrared spectra, which has implications for observations of interstellar ice spectra. Laboratory TPD data also show that the three isomers can be distinguished on the basis of their thermal desorption behaviour. In particular, TPD data show that the isomers cannot be treated the same way in astrophysical models of desorption. The desorption of glycolaldehyde and acetic acid from water-dominated ices is very similar, with desorption being mainly dictated by water ice. However, methyl formate also desorbs from the surface of the ice, as a pure desorption feature, and therefore desorbs at a lower temperature than the other two isomers. This is more clearly indicated by models of the desorption on astrophysical time-scales corresponding to the heating rate of 25 and 5 M-circle dot stars. For a 25 M-circle dot star, our model shows that a proportion of the methyl formate can be found in the gas phase at earlier times compared to glycolaldehyde and acetic acid. This has implications for the observation and detection of these molecules, and potentially explains why methyl formate has been observed in a wider range of astrophysical environments than the other two isomers.