title: Chandrasekhar mass explosions of white dwarfs  as a model for type Ia supernovae and  their contribution to cosmic nucleosynthesis
creator: Lach, Florian
subject: ddc-500
subject: 500 Natural sciences and mathematics
subject: ddc-520
subject: 520 Astronomy and allied sciences
subject: ddc-530
subject: 530 Physics
description: Although type Ia supernovae are widely applied as cosmological distance indicators and  contribute significantly to the enrichment of the Universe with iron group elements, their physi-  cal nature is not clear yet. The heterogeneous class of type Ia supernovae is divided into several  subtypes according to their observational properties, and a whole variety of possible explosion  scenarios has been put forward in order to explain these extraordinarily bright events. The focus  of this work lies on the numerical modeling of explosions in Chandrasekhar mass carbon-oxygen  white dwarfs as well as on the investigation of the nucleosynthesis yields of several explosion chan-  nels. To this end, numerical simulations of the explosion, the propagation of radiation through the  expanding debris, and the galactic chemical evolution of the Milky Way were conducted. It was  found that, in line with earlier studies, deflagrations in Chandrasekhar mass white dwarfs are a  viable model for type Iax supernovae, a subluminous subclass of type Ia supernovae. However,  the parameter study employing different ignition conditions, central densities, metallicities, com-  position and rigid rotation revealed that the very faint end of the subclass can not be reproduced.  Furthermore, a set of gravitationally confined detonation simulations has been carried out. In this  scenario an initial deflagration is followed by a detonation initiated near the surface of the white  dwarf core. It could be shown that the synthetic observables do not agree with either normal or  subluminous type Ia supernovae but that objects similar to SN 1991T might be explained by this  explosion mechanism. Finally, the nucleosynthesis yields of various different explosion models  were analyzed. This study shows that explosions in sub-Chandrasekhar mass white dwarfs with an  accreted helium shell can contribute significantly to the abundance of manganese, zinc, and copper  in the Universe and should be included in future galactic chemical evolution studies.
date: 2022
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/31666/1/PhD_FlorianLach.pdf
identifier: DOI:10.11588/heidok.00031666
identifier: urn:nbn:de:bsz:16-heidok-316660
identifier:   Lach, Florian  (2022) Chandrasekhar mass explosions of white dwarfs as a model for type Ia supernovae and their contribution to cosmic nucleosynthesis.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/31666/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng