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Title: A SPITZER/INFRARED SPECTROGRAPH SPECTRAL STUDY OF A SAMPLE OF GALACTIC CARBON-RICH PROTO-PLANETARY NEBULAE

Recent infrared spectroscopic observations have shown that proto-planetary nebulae (PPNs) are sites of active synthesis of organic compounds in the late stages of stellar evolution. This paper presents a study of Spitzer/Infrared Spectrograph spectra for a sample of carbon-rich PPNs, all except one of which show the unidentified 21 {mu}m emission feature. The strengths of the aromatic infrared band, 21 {mu}m, and 30 {mu}m features are obtained by decomposition of the spectra. The observed variations in the strengths and peak wavelengths of the features support the model that the newly synthesized organic compounds gradually change from aliphatic to aromatic characteristics as stars evolve from PPNs to planetary nebulae.
Authors:
;  [1] ;  [2]
  1. Department of Physics, University of Hong Kong, Pokfulam Rd. (Hong Kong)
  2. Department of Physics and Astronomy, Valparaiso University, Valparaiso, IN 46383 (United States)
Publication Date:
OSTI Identifier:
21474397
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 725; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/725/1/990
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON; DECOMPOSITION; EMISSION; ORGANIC COMPOUNDS; PLANETARY NEBULAE; SPECTRA; STAR EVOLUTION; STARS CHEMICAL REACTIONS; ELEMENTS; EVOLUTION; NEBULAE; NONMETALS