Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603232
Title: The intriguing chemistry of NGC 6302
Author: Hebden, Kerry Louise
ISNI:       0000 0004 5355 6336
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2014
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Abstract:
The hostile circumstellar environment of an emerging protoplanetary nebula (PPN) and its transformation to a planetary nebula (PN) is an area of active observation and yet, many uncertainties still exist, not least in explanations of molecular abundances. Additionally, the combination of extreme radiation fields, X-rays and high velocity shocks may also drive interesting and possible novel chemical reactions and pathways. Thorough molecular surveys on PNe are minimal and in-depth modelling of specific sources to explain observed molecular abundances, are also limited in the literature. Modelling of species such as H2O within a PN, have yet to be explored in detail at all. This thesis describes observations of NGC 6302, a young butterfly PN with possibly the highest identified central mass of any known PN (∼2-3 M⊙), which have recently been undertaken at the SMA. Image maps and spectra for a number of molecular species were obtained in order to provide further insights into chemical behaviour within a PN. Observational results have been compared with detailed modelling to as- certain the role of various environmental factors on the chemistry within NGC 6302. It was found that an outflow could possibly be responsible for enhanced emission for HCO+, HCN and SiO. Species such as 13CS and 29SiC2 are also enhanced in the direction of the bi-polar lobes. N2H+ is confined to the dense torus, with CN also displaying little enhancement beyond the CO emission. Models suggest that whilst SO2 is abundant in low oxygen abundances but nitrogen-enriched dense clouds, H2O can be produced efficiently in all environments. It was also found that in standard models, H2O reactions proceed differently to H2O formation in dense-cloud models and circumstellar envelopes.
Supervisor: Fuller, Gary Sponsor: STFC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.603232  DOI: Not available
Keywords: NGC 6302, Planetary Nebulae, Chemistry, Millimeter Observations, Interferometry, Chemical Modelling
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