Here we present the results of an airborne 3-5.4$\mu$m spectroscopic study of three young, Carbon-rich planetary nebulae IC 5117, PNG 093.9-00.1, and BD $+$30 3639. These observations were made using the grism spectroscopy mode of the FLITECAM instrument during airborne science operations onboard NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA). The goal of this study is to characterize the 3.3 $\mu$m and 5.25 $\mu$m PAH dust emission in planetary nebulae and study the evolution of PAH features within evolved stars before their incorporation into new stellar systems in star-forming regions. Targets were selected from IRAS, KAO and ISO source lists, and were previously observed with FLITECAM on the 3-meter Shane telescope at Lick Observatory to allow direct comparison between the ground and airborne observations. We measure PAH emission equivalent width and central wavelength, classify the shape of the PAH emission, and determine the PAH/Aliphatic ratio for each target. The 3.3 $\mu$m PAH emission feature is observed in all three objects. PNG 093.9-00.1 exhibits NGC 7027-like aliphatic emission in the 3.4 to 3.6 $\mu$m region while IC 5117 and BD +30 3639 exhibit less aliphatic structure. All three PNs additionally exhibit PAH emission at 5.25 $\mu$m.

中文翻译：

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使用 SOFIA/FLITECAM 对来自行星状星云的 3-5.4 μm 辐射的调查

在这里，我们展示了对三个年轻的、富含碳的行星状星云 IC 5117、PNG 093.9-00.1 和 BD $+$30 3639 进行的机载 3-5.4$\mu$m 光谱研究的结果。这些观察结果是使用 grism 光谱进行的FLITECAM 仪器在 NASA 平流层红外天文台 (SOFIA) 机载科学操作期间的模式。本研究的目标是表征行星状星云中 3.3 $\mu$m 和 5.25 $\mu$m 的 PAH 尘埃排放，并研究演化恒星内部 PAH 特征在它们并入恒星形成区域的新恒星系统之前的演化. 目标是从 IRAS、KAO 和 ISO 源列表中选择的，并且之前在 Lick 天文台的 3 米 Shane 望远镜上使用 FLITECAM 进行了观测，以便在地面和机载观测之间进行直接比较。我们测量 PAH 发射等效宽度和中心波长，对 PAH 发射的形状进行分类，并确定每个目标的 PAH/脂肪族比率。在所有三个物体中都观察到了 3.3 $\mu$m PAH 发射特征。PNG 093.9-00.1 在 3.4 到 3.6 $\mu$m 区域表现出类似 NGC 7027 的脂肪族发射，而 IC 5117 和 BD +30 3639 表现出较少的脂肪族结构。所有三个 PN 还表现出 5.25 $\mu$m 的 PAH 排放。