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Recent astronomical observations and planetary missions have found that complex organics are prevalent throughout the universe, from the solar system to distant galaxies. However, the detailed chemical composition and the synthesis pathway of these organics are still unclear. Circumstellar envelopes represent excellent laboratories to study the abiological synthesis of extraterrestrial organics. Novae, having very short dynamical lifetimes, can put severe constraints on the chemical pathway of organic synthesis. Here, we report a laboratory simulation of carbonaceous dust with inclusion of Nitrogen in the form of Quenched Nitrogen-included Carbonaceous Composite (QNCC). QNCC is produced by the quenched condensation of plasma gas generated from the nitrogen gas, and aromatic and/or aliphatic hydrocarbon solids by applying microwave discharge (2.45 GHz, 300 W). We have shown that the spectra of QNCC have a close resemblance to the observed infrared spectra of novae. The results of the infrared and X-ray analyses suggest that the nitrogen inclusion in the form of amine plays an important role in the origin of the broad 8 μm feature of dusty novae. We conclude that QNCC is at present the best laboratory analog of organic dust formed in the circumstellar medium of dusty classical novae, which carries the unidentified infrared bands in novae via thermal emission process.

WR 112 is a dust-forming carbon-rich Wolf-Rayet (WC) binary with a dusty circumstellar nebula that exhibits a complex asymmetric morphology, which traces the orbital motion and dust formation in the colliding winds of the central binary. Unraveling the complicated circumstellar dust emission around WR 112 therefore provides an opportunity to understand the dust formation process in colliding-wind WC binaries. In this work, we present a multi-epoch analysis of the circumstellar dust around WR 112 using seven high spatial resolution (FWHM $\sim0.3-0.4''$) N-band ($\lambda \sim12$ $\mu$m) imaging observations spanning almost 20 years and includes newly obtained images from Subaru/COMICS in Oct 2019. In contrast to previous interpretations of a face-on spiral morphology, we observe clear evidence of proper motion of the circumstellar dust around WR 112 consistent with a nearly edge-on spiral with a $\theta_s=55^\circ$ half-opening angle and a $\sim20$-yr period. The revised near edge-on geometry of WR 112 reconciles previous observations of highly variable non-thermal radio emission that was inconsistent with a face-on geometry. We estimate a revised distance to WR 112 of $d = 3.39^{+0.89}_{-0.84}$ kpc based on the observed dust expansion rate and a spectroscopically derived WC terminal wind velocity of $v_\infty= 1230\pm260$ km s$^{-1}$. With the newly derived WR 112 parameters we fit optically-thin dust spectral energy distribution models and determine a dust production rate of $\dot{M}_d=2.7^{+1.0}_{-1.3}\times10^{-6}$ M$_\odot$ yr$^{-1}$, which demonstrates that WR 112 is one of the most prolific dust-making WC systems known.