Millimeter Spectroscopic Survey of Young Planetary Nebula NGC 7027
Date Issued
2007
Date
2007
Author(s)
Huang, Yu-Chin
DOI
en-US
Abstract
In this thesis, we investigate the molecular content of the NGC 7027, the young and extensively studied planetary nebula for which there is no spectral line survey covering the whole 3mm band and 1.3mm band. Since April 2005, we have carried out the spectral line survey in the 3 mm band (72-95 GHz) and part of 1.3 mm band (220-243 GHz and 246-266 GHz) using the Arizona Radio Observatory (ARO) 12m and 10m telescopes. We detect 39 lines from 7 known interstellar molecules, 6 hydrogen recombination lines and one unidentified line. The detected molecules include CO, and its isotopomers, hyperfine transitions of CN, HCN, C2H, and molecular ions, HCO+, N2H+ and CO+. By using our data, we study the molecular content of NGC 7027 and
understand the physical environment as proposed in previous studies. Moreover, the spectral lines show characteristics of ionized central region, and the presence of photodissociation region, where photochemistry is very active. Besides, our study on NGC 7027 is part of a bigger survey project, which aims to observe IRC+10216,
CIT 6, CRL 2688, and NGC 7027. These four sources span the
asymptotic giant branch(AGB)phase, the proto-planetary nebula phase, and the planetary nebula(PN) phase respectively. The result will allow us to study the chemical evolution from AGB phase to PN phase.
Subjects
譜線確認
譜線譜查
恆星:漸近巨星分支
行星狀星雲:單一星雲(NGC 7027)
環星物質
line identification
surveys
stars : AGB
planetary nebulae : individual(NGC 7027)
circumstellar matter
Type
other
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