TIMASSS：IRAS16293-2422毫米和亚毫米光谱调查：氘代甲酸甲酯（DCOOCH3）的初步检测
TIMASSS : The IRAS16293-2422 Millimeter And Submillimeter Spectral Survey: Tentative Detection of Deuterated Methyl Formate (DCOOCH3)
摘要：
在星前核、热核和热科里诺等不同类型的环境中都观察到了高氘分馏。它已被证明是研究这些环境的物理和化学条件的有效探针。研究不同分子的氘化反应有助于我们理解它们的形成。这对于复杂的分子如甲醇和更大的分子特别有趣，因为它可以区分气相和固态形成途径。甲醇在热的可里诺中表现出很高的氘分馏。由于CH3OH被认为是甲酸甲酯的前体，我们预计在这样的环境中会产生氘代甲酸甲酯。我们已经在IRAS 16293 - 2422中寻找甲酸甲酯的单氘同位素体DCOOCH 3，IRAS 16293 - 2422是一种以其高度甲醇氘代而闻名的热科里诺。我们已经使用IRAM/JCMT无偏光谱调查IRAS 16293 - 2422，这使我们能够搜索的DCOOCH 3旋转跃迁的调查光谱范围内（80 - 280 GHz，328 - 366 GHz）。氘代甲酸甲酯的预期排放在LTE下建模，并与观测结果进行比较。我们在原恒星IRAS 16293 - 2422中初步检测到DCOOCH 3。我们将IRAM调查中检测到的八条线分配给DCOOCH 3。其中三条线路受到混合问题的影响，一条线路受到校准不确定性的影响，但LTE排放模型与观测结果一致。IRAS 16293 - 2422中两个核心的简单LTE建模，基于先前对HCOOCH 3的干涉研究，允许我们估计IRAS 16293 - 2422中DCOOCH 3的量。采用激发温度为100 K，A芯和B芯的源尺寸分别为2 \arcsec和1 \farcs 5，我们发现N（A，DCOOCH 3）= N（B，DCOOCH 3）~6.10^14/cm 2。导出的氘分馏约为15%，与该来源中其他氘代物质的值一致，并且远大于氘宇宙丰度的预期值。DCOOCH 3，如果它的初步检测得到证实，现在应该考虑在理论模型，研究复杂的分子形成和它们的氘化机制。还需要开展实验工作，调查导致形成氘代甲酸甲酯的不同化学途径。
英文摘要：
High deuterium fractionation is observed in various types of environment such as prestellar cores, hot cores and hot corinos. It has proven to be an efficient probe to study the physical and chemical conditions of these environments. The study of the deuteration of different molecules helps us to understand their formation. This is especially interesting for complex molecules such as methanol and bigger molecules for which it may allow to differentiate between gas-phase and solid-state formation pathways. Methanol exhibits a high deuterium fractionation in hot corinos. Since CH3OH is thought to be a precursor of methyl formate we expect that deuterated methyl formate is produced in such environments. We have searched for the singly-deuterated isotopologue of methyl formate, DCOOCH3, in IRAS 16293-2422, a hot corino well-known for its high degree of methanol deuteration. We have used the IRAM/JCMT unbiased spectral survey of IRAS 16293-2422 which allows us to search for the DCOOCH3 rotational transitions within the survey spectral range (80-280 GHz, 328-366 GHz). The expected emission of deuterated methyl formate is modelled at LTE and compared with the observations.} We have tentatively detected DCOOCH3 in the protostar IRAS 16293-2422. We assign eight lines detected in the IRAM survey to DCOOCH3. Three of these lines are affected by blending problems and one line is affected by calibration uncertainties, nevertheless the LTE emission model is compatible with the observations. A simple LTE modelling of the two cores in IRAS 16293-2422, based on a previous interferometric study of HCOOCH3, allows us to estimate the amount of DCOOCH3 in IRAS 16293-2422. Adopting an excitation temperature of 100 K and a source size of 2\arcsec and 1\farcs5 for the A and B cores, respectively, we find that N(A,DCOOCH3) = N(B,DCOOCH3) ~ 6.10^14 /cm2. The derived deuterium fractionation is ~ 15%, consistent with values for other deuterated species in this source and much greater than that expected from the deuterium cosmic abundance. DCOOCH3, if its tentative detection is confirmed, should now be considered in theoretical models that study complex molecule formation and their deuteration mechanisms. Experimental work is also needed to investigate the different chemical routes leading to the formation of deuterated methyl formate.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
