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We have succeeded in synthesizing organics, ‘Quenched Nitrogen-included Carbonaceous Composite (QNCC)’, via plasma chemical vapor deposition (CVD) method, whose infrared spectral properties reproduce the characteristics of the unidentified infrared (UIR) bands observed around classical novae. Past studies have shown that the UIR bands observed around novae appear somewhat differently from those observed in other astrophysical environment and are predominantly characterized by the presence of a broad 8μm feature. The remarkable similarity between the infrared properties of QNCC and the UIR bands in novae indicates that QNCC should be considered as a strong candidate of the carriers of the UIR bands in novae. Finally, we have started a space exposure experiment of QNCC aiming to explore the evolutional link between the QNCC and the insoluble organic molecule (IOM) in carbonaceous condrite and, thus, to infer the origins of organics in our solar system.

The unidentified infrared (UIR) bands have been ubiquitously observed in various astrophysical environments and consist of a series of emission features arising from aromatic and/or aliphatic C-C and C-H bonds [1]. Therefore, their carriers are thought to be related to interstellar organics. However, our knowledge on the true carriers of the UIR bands is still limited. Recently [4] has proposed Mixed Aromatic Aliphatic Organic Nanoparticles, which contains hetero atoms in addition to conventional hydrocarbon models, as a more realistic interpretation of the band carriers. The challenges toward identifying the carriers of the UIR bands are still ongoing. Past studies have shown that the UIR bands observed around classical novae, which characterized by the presence of broad feature around 8μm[2], are somewhat different from those observed in other astrophysical environment. Here we report the success of experimentally synthesizing the organics called Nitrogen-included Carbonaceous Compounds (NCC; [7]) whose infrared properties can reproduce the UIR bands observed in classical novae.

The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently concluded a set of engineering flights for Observatory performance evaluation. These in-flight opportunities are viewed as a first comprehensive assessment of the Observatory's performance and are used to guide future development activities, as well as to identify additional Observatory upgrades. Pointing stability was evaluated, including the image motion due to rigid-body and flexible-body telescope modes as well as possible aero-optical image motion. We report on recent improvements in pointing stability by using an active mass damper system installed on the telescope. Measurements and characterization of the shear layer and cavity seeing, as well as image quality evaluation as a function of wavelength have also been performed. Additional tests targeted basic Observatory capabilities and requirements, including pointing accuracy, chopper evaluation and imager sensitivity. This paper reports on the data collected during these flights and presents current SOFIA Observatory performance and characterization., Comment: 13 pages, 13 figure, and 2 tables; accepted by ApJS