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Diffraction-limited 3 um Spectroscopy of IRAS 04296+3429 and IRAS 05341+0852: Spatial Extent of Hydrocarbon Dust Emission and Dust Evolutionary Sequence

M. Goto·Sun Kwok·H. Takami·M. Hayashi·W. Gaessler·Y. Hayano·M. Iye·Y. Kamata·T. Kanzawa·N. Kobayashi·Y. Minowa·K. Nedachi·S. Oya·T. -S. Pyo·D. Saint-Jacques·N. Takato·H. Terada·Th. Henning
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Abstract

We present 3 um spectroscopy of the carbon-rich proto-planetary nebulae IRAS 04296+3429 and IRAS 05341+0852 conducted with the adaptive optics system at the Subaru Telescope. We utilize the nearly diffraction-limited spectroscopy to probe the spatial extent of the hydrocarbon dust emitting zone. We find a hydrocarbon emission core extending up to 100--160 mas from the center of IRAS 04296+3429, corresponding to a physical diameter of 400--640 AU, assuming a distance of 4 kpc. On the other hand, we find that IRAS 05341+0852 is not spatially resolved with this instrumentation. The physical extent of these proto-planetary nebulae, along with the reanalyzed data of IRAS 22272+5435 published previously, suggests a correlation between the physical extent of the hydrocarbon dust emission and the spectral evolution of the aliphatic to aromatic features in these post-AGB stars. These measurements represent the first direct test of the proposed chemical synthesis route of carbonaceous dust in the circumstellar environment of evolved stars.

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M. Goto, Sun Kwok, H. Takami, M. Hayashi, W. Gaessler, Y. Hayano, M. Iye, Y. Kamata, T. Kanzawa, N. Kobayashi, Y. Minowa, K. Nedachi, S. Oya, T. -S. Pyo, D. Saint-Jacques, N. Takato, H. Terada, Th. Henning. 2006-11-29. Diffraction-limited 3 um Spectroscopy of IRAS 04296+3429 and IRAS 05341+0852: Spatial Extent of Hydrocarbon Dust Emission and Dust Evolutionary Sequence. https://doi.org/10.1086/511126

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