Program: GS-2010B-C-7

Dust forming Novae provide us valuable opportunities to explore the process of formation and evolution of dust in the nova ejecta. In this program, we plan to carry out the mid-infrared spectroscopy of dust-forming nova V1280 Sco at the epoch of 1300 days after the outburst. Mid-infrared spectroscopic observations are quite useful to investigate the detailed chemical properties of HACs formed in the nova ejecta. This program has a strong merit in that, combined with the near-infrared (2-5 micron) spectra of V1280 Sco obtained with AKARI/IRC at epochs of 940days (and 1300days), the chemical evolution scenario of carbonaceous dust is examined by making use of the extraordinary bright dust forming nova V1280 Sco and other dust forming novae. Through this program, the knowledge on the chemical evolution of Hydrogenated Amorphous Carbons (HACs) from "aliphatic" to "aromatic" by the irradiation of nova UV flux will be obtained. The obtained results may provide us important additional support for the scenario that HACs may become the possible sources of free-flying polycyclic aromatic hydrocarbons (PAHs) via the shattering process of in the mild (~100km/s) interstellar shocks.