THERMAL-PROCESSING OF CARBON DUST AROUND A COOL STAR | ||||
| Al-Azhar Bulletin of Science | ||||
| Article 3, Volume 2014, Issue 6, June 2014, Page 1-6 PDF (634.48 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/absb.2014.22659 | ||||
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| Author | ||||
| Gadallah K. A. K.* | ||||
| Department of Astronomy & Meteorology, Faculty of Science, Al-Azhar University, Nasr City | ||||
| Abstract | ||||
| Thermal-processed carbonaceous materials could emulate the evolution of the carbonaceous dust which settles in regions around a cool star in a proto-planetary nebula (PPN). Spectroscopically, this evolution has been shown through the variation in the strength of the aliphatic (-C-H stretching mode at the 3.42 μm) band relative to those of the aromatic (=C-H mode at the 3.3 μm) band. Experimentally, the laser ablation technique was used to produce the Hydrogenated Amorphous Carbon (HAC) samples as analogs of comic carbon dust. The IR-laboratory data of these samples shows that the strength of these two bands varies reversely to each other as HAC transforms from the aliphatic to aromatic structure with heating. The temperature, required to cause this transformation within HAC, depends on its hydrogen content. Hence, the trend of this variation is also in relevance to the hydrogen content within HAC. This trend shows the variation from the aliphatic to aromatic structure in dust grains in regions within the PPN IRAS 22272+5435. In which, it is expected that dust grains may be heated in the past in the warm region near the star. | ||||
| Keywords | ||||
| Comic carbon dust; IR spectroscopy; Planetary nebulae | ||||
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