In April 2016 Manchester eScholar was replaced by the University of Manchester’s new Research Information Management System, Pure. In the autumn the University’s research outputs will be available to search and browse via a new Research Portal. Until then the University’s full publication record can be accessed via a temporary portal and the old eScholar content is available to search and browse via this archive.

The Intriguing Chemistry of NGC 6302

Hebden, Kerry Louise

[Thesis]. Manchester, UK: The University of Manchester; 2014.

Access to files

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.

Bibliographic metadata

Type of resource:
Content type:
Form of thesis:
Type of submission:
Degree type:
Doctor of Philosophy
Degree programme:
PhD Astronomy & Astrophysics (42 month)
Publication date:
Location:
Manchester, UK
Total pages:
192
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.
Thesis main supervisor(s):
Thesis advisor(s):
Funder(s):
Language:
en

Institutional metadata

University researcher(s):

Record metadata

Manchester eScholar ID:
uk-ac-man-scw:220845
Created by:
Hebden, Kerry
Created:
8th March, 2014, 12:10:17
Last modified by:
Hebden, Kerry
Last modified:
11th July, 2015, 12:17:51

Can we help?

The library chat service will be available from 11am-3pm Monday to Friday (excluding Bank Holidays). You can also email your enquiry to us.