Silicon and carbon abundances in the Orion nebula
Silicon and carbon abundances in the Orion nebula
复制标题
猎户座星云中硅和碳的丰度
DOI：
10.1086/172992
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
D. Walter
中科院分区：
文献类型：
--
作者：
R. Rubin;R. Dufour;D. Walter
我们评估了气相丰度的Si和C从我们最近的测量Si（2+），C（2+），和C（+）在猎户座星云扩大我们早期的“水泡”模型。C和Si的丰度来自新的IUE高色散光谱的C（2+）1907，1909 A和Si（2+）1883，1892 A线和档案IUE数据。气相Si/C = 0.016的猎户座电离体积，是特别不敏感的消光和温度结构的不确定性。太阳值为0.098。气相C/H = 2.8 x 10 exp-4和Si/H = 4.5 x 10 exp-6。与太阳能相比，Si在电离区域中被耗尽约8倍，而C被耗尽得少得多（1.3倍），如果完全耗尽的话。这表明，即使在电离体积中，大多数Si也存在于尘埃颗粒中。因此，大多数观察到的禁止硅II 34.8微米发射猎户座不会出现在H II区域。
We assess the gas-phase abundances of Si and C from our recent measurements of Si(2+), C(2+), and C(+) in the Orion Nebula by expanding on our earlier 'blister' models. The C and Si abundances are derived from new IUE high-dispersion spectra of the C(2+) 1907, 1909 A and Si(2+) 1883, 1892 A lines and archival IUE data. Gas-phase Si/C = 0.016 in the Orion ionized volume and is particularly insensitive to uncertainties in extinction and temperature structure. The solar value is 0.098. Gas-phase C/H = 2.8 x 10 exp -4 and Si/H = 4.5 x 10 exp -6. Compared to solar, Si is depleted by a factor of about 8 in the ionized region, while C is much less depleted (factor of 1.3), if depleted at all. This suggests that most Si resides in dust grains even in the ionized volume. Thus, most of the observed forbidden Si II 34.8-micron emission in Orion does not arise in the H II region.