Water Ice, Silicate and PAH Emission Features in the ISO Spectrum of the Carbon-rich Planetary Nebula CPD-56 8032

Martin Cohen; M. J. Barlow; R. J. Sylvester; X. -W. Liu; P. Cox; T. Lim; B. Schmitt; A. K. Speck

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Water Ice, Silicate and PAH Emission Features in the ISO Spectrum of the Carbon-rich Planetary Nebula CPD-56 8032

Martin Cohen·M. J. Barlow·R. J. Sylvester·X. -W. Liu·P. Cox·T. Lim·B. Schmitt·A. K. Speck

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Abstract

Combined ISO SWS and LWS spectroscopy is presented of the late WC-type planetary nebula nucleus CPD-56 8032 and its carbon-rich nebula. The extremely broad coverage (2.4-197 microns) enables us to recognize the clear and simultaneous presence of emission features from both oxygen- and carbon- rich circumstellar materials. Removing a smooth continuum highlights bright emission bands characteristic of polycyclic aromatic hydrocarbons (hereafter PAHs) in the 3-14 micron region, bands from crystalline silicates longwards of 18 microns, and the 43- and 62-micron bands of crystalline water ice. We discuss the probable evolutionary state and history of this unusual object in terms of (a) a recent transition from an O-rich to a C-rich outflow following a helium shell flash; or (b) a carbon-rich nebular outflow encountering an O-rich comet cloud.

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Martin Cohen, M. J. Barlow, R. J. Sylvester, X. -W. Liu, P. Cox, T. Lim, B. Schmitt, A. K. Speck. 1999-01-11. Water Ice, Silicate and PAH Emission Features in the ISO Spectrum of the Carbon-rich Planetary Nebula CPD-56 8032. https://arxiv.org/abs/astro-ph/9901126

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