Seimei KOOLS-IFU Mapping of the Gas and Dust Distributions in Galactic Planetary Nebulae: the Case of IC2165

Abstract

We investigated the physical and chemical properties of the gas and dust components in a carbon-rich planetary nebula (PN) IC2165 using two-dimensional (2-D) emission-line maps with superior resolution. The extinction map is generated in a selfconsistent and assumption-free manner. The circumstellar gas-to-dust mass ratio (GDR) map ranges radially from 1210 in the central nebula filled with hot gas plasma to 120 near the ionisation front. The determined GDR is comparable to ∼400, which is commonly adopted for carbon-rich asymptotic giant branch (AGB) stars, and ∼100 for ISM. Except for the inner regions, the GDR in IC2165 is nearly the same as in such AGB stars, indicating that most dust grains withstand the harsh radiation field without being destroyed. The gas and dust mass distributions concentrated in the equatorial plane may be related to the nonisotropic mass loss during the AGB phase and nebula shaping. The spatial distributions of electron densities/temperatures and ionic/elemental abundances were investigated herein. We determined 13 elemental abundances using PSF-matched spatially integrated multiwavelength spectra extracted from the same aperture. Their values are consistent with values predicted by a theoretical model for stars of initially 1.75 M and 𝑍 = 0.003. Finally, we constructed the photoionisation model using our distance measurement to be consistent with all derived quantities, including the GDR and gas and dust masses and post-AGB evolution. Thus, we demonstrate the capability of Seimei/KOOLS-IFU and how the spatial variation of the gas and dust components in PNe derived from IFU observations can help understand the evolution of the circumstellar/interstellar medium.