Unusual Carbonaceous Dust Distribution in PN G095.2+00.7
Abstract
We investigate the polycyclic aromatic hydrocarbon (PAH) features in the young Galactic planetary nebula PN G095.2+00.7 based on mid-infrared observations. The near- to mid-infrared spectra obtained with the AKARI/IRC and the Spitzer/IRS show the PAH features as well as the broad emission feature at 12 μm usually seen in proto-planetary nebulae (pPNe). The spatially resolved spectra obtained with Subaru/COMICS suggest that the broad emission around 12 μm is distributed in a shell-like structure, but the unidentified infrared band at 11.3 μm is selectively enhanced at the southern part of the nebula. The variation can be explained by a difference in the amount of the UV radiation to excite PAHs, and does not necessarily require the chemical processing of dust grains and PAHs. It suggests that the UV self-extinction is important to understand the mid-infrared spectral features. We propose a mechanism which accounts for the evolutionary sequence of the mid-infrared dust features seen in a transition from pPNe to PNe.
Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2012
- DOI:
- arXiv:
- arXiv:1211.2385
- Bibcode:
- 2012ApJ...760L..34O
- Keywords:
-
- circumstellar matter;
- infrared: ISM;
- planetary nebulae: individual: PN G095.2+00.7;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Galaxy Astrophysics
- E-Print:
- 6 pages, 4 figures