Molecules and the dynamics of SN 1987A

Davies, Holly 2024. Molecules and the dynamics of SN 1987A. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Molecular emission has helped diagnose physical properties and conditions of many astronomical objects in the ISM. Recently, molecular emission has been observed in the ejecta of supernova remnant SN 1987A. On-going observations of SN 1987A since its explosion have been key to understanding how a young core collapse supernova remnant evolves across time. For this master's thesis, I analyse high angular resolution observations of the emission from two HCO+ transitions at J=3-2 and J=4-3 using the Atacama Large Millimetre Array (ALMA). From these observations, I highlight any potential chemical reactions which could form HCO+ in the ejecta. I compare the spatial distribution of the J=3-2 HCO+ emission with that of the J=2-1 CO emission and find that their brightest peaks are co-located and show a strong correlation suggesting that HCO+ may form from CO. In order to form HCO+, a moderate amount of hydrogen needs to be mixed into the carbon/oxygen rich regions of the ejecta. This may occur through hydrodynamical mixing of elements within the remnant before and during the supernova explosion. I speculate that, alongside large-scale, macroscopic mixing of clumps of elements known to occur in the remnant, forms of smaller-scale mixing from smaller elemental clumps down to atomic-level mixing at clump interfaces or boundary layers of different elements could also occur. To confirm the findings of this thesis, an extensive chemical network of HCO+ formation in the remnant environment of SN 1987A is required. My HCO+ analysis however, provides insight into the mixing and chemistry that can occur within the remnant which can open up new routes of hydrogen chemistry previously not considered for SN 1987A and potentially be applicable to other young supernova remnants.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QC Physics
Uncontrolled Keywords:	SN 1987A, Supernova, Supernovae Remnants, Molecules, Radio Lines.
Funders:	STFC
Date of First Compliant Deposit:	20 January 2025
Last Modified:	20 Jan 2025 15:50
URI:	https://orca.cardiff.ac.uk/id/eprint/175384

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