Detection of triply deuterated ammonia in the Barnard 1 cloud
Detection of triply deuterated ammonia in the Barnard 1 cloud
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DOI：
10.1086/341132
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发表时间：
2002-05-20
影响因子：
4.9
通讯作者：
Schilke, P
中科院分区：
文献类型：
--
作者：
Lis, DC;Roueff, E;Schilke, P
我们报道了用加州理工大学亚毫米天文台在巴纳德1云中探测到的309.91 GHz三氢氨的基态转动跃迁J(K)=1(0)-->；0(0)(0A-->；0)。观测到的0.307+/-0.019 K公里的积分谱线强度S(-1)意味着，在5-10K的激发温度范围内，Nd3的柱密度为(2+/-0.9x10(12)cm(-2))，利用之前发表的H-2和NH3柱密度的估计，我们得到了相对于H-2的Nd3部分丰度为(1.5K+/-1)x10(-11)，以及Nd3与NH3的丰度比类似于8×10(-4)。观察到的丰度比可以在气相化学模型的框架内得到解释，在气相化学模型中，部分氘离子的解离复合导致氢原子抛射的概率略高于氢原子。
We report the detection of the ground-state rotational transition J(K) = 1(0) --> 0(0) (0a --> 0s) of triply deuterated ammonia at 309.91 GHz in the Barnard 1 cloud, obtained with the Caltech Submillimeter Observatory. The observed, integrated, line intensity of 0.307 +/- 0.019 K km s(-1) implies an ND3 column density of (2 +/- 0.9) x 10(12) cm(-2), for excitation temperatures in the range 5-10 K. Using previously published H-2 and NH3 column density estimates in this source, we derive an ND3 fractional abundance with respect to H-2 of (1.5 +/- 1) x 10(-11) and an ND3-to-NH3 abundance ratio of similar to8 x 10(-4). The observed abundance ratios can be explained in the framework of gas-phase chemical models, in which the dissociative recombination of partially deuterated ions results in a somewhat higher probability for the ejection of hydrogen atoms than deuterium.