标题： NGC 7538 IRS 1的高分辨率中红外光谱：探测大质量年轻恒星天体中的化学物质 显示英文标题

标题： High Resolution Mid-Infrared Spectroscopy of NGC 7538 IRS 1: Probing Chemistry in a Massive Young Stellar Object

摘要： 我们展示了来自NGC 7538恒星形成区高致密年轻恒星IRS 1的高分辨率（R = 75,000-100,000）中红外光谱。观察到了许多C2H2、13C12CH2、CH3、CH4、NH3、HCN、HNCO和CS的旋转状态的吸收线。推导了每种分子的气体温度、柱密度、覆盖因子、线宽和多普勒位移。所有分子都用介于-54到-63 km/s之间的两个速度组分拟合。与之前报道的值相比，我们发现所有观测到的分子具有高的柱密度（~ 10e16 cm^2），并给出了CH3和HNCO的新结果。考虑了几种物理和化学模型。首选模型涉及围绕大质量恒星的近边缘盘。内盘尘埃辐射穿过盘大气层，在那里大的分子柱密度可以产生所观测到的吸收线光谱。 显示英文摘要

摘要： We present high resolution (R = 75,000-100,000) mid-infrared spectra of the high-mass embedded young star IRS 1 in the NGC 7538 star-forming region. Absorption lines from many rotational states of C2H2, 13C12CH2, CH3, CH4, NH3, HCN, HNCO, and CS are seen. The gas temperature, column density, covering factor, line width, and Doppler shift for each molecule are derived. All molecules were fit with two velocity components between -54 and -63 km/s. We find high column densities (~ 10e16 cm^2) for all the observed molecules compared to values previously reported and present new results for CH3 and HNCO. Several physical and chemical models are considered. The favored model involves a nearly edge-on disk around a massive star. Radiation from dust in the inner disk passes through the disk atmosphere, where large molecular column densities can produce the observed absorption line spectrum.