The reaction flow during explosive nuclear burning on an accreting neutron star

Fisker, Jacob Lund. The reaction flow during explosive nuclear burning on an accreting neutron star. 2005, PhD Thesis, University of Basel, Faculty of Science.


Official URL: http://edoc.unibas.ch/diss/DissB_7350

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This dissertation contains the first extensive investigation of the detailed reaction flow of an X-ray burst under realistic conditions. It was made possible by building a new computational model. This model distinguishes itself by introducing for the first time: full general relativistic (GR) hydrodynamical equations, GR corrected atmosphere, GR corrected convection, modern approximations of the opacities and conductivities, neutrino losses, and a GR inner boundary of the core luminosity. We use conservative equations allowing a precise tracking off all released energy which reveals unprecedented details in the luminosity. The simulations show that – • An interplay between the helium flash and the rp-process produces an identifiable double-peaked structure, which has been observed. • The burst temperature is lower than previously assumed, so the Tecycle is not reached. The average mass of the ashes is ∼ 64. Carbon is destroyed by helium captures before reaching the ocean. • Convection does not hit the surface for mixed hydrogen/helium bursts. Therefore we predict that burst spectral lines are not from material from deeper layers. • Convection extends to the surface in helium ignited bursts. We predict a sudden rise in helium and sulfur as the turbulent overturn breaches the surface. We also give a complete description of the X-rat burst reaction flow including branchings and waiting points as a guide to future experiments and observations.
Advisors:Thielemann, Friedrich-Karl
Committee Members:Schatz, H.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Theoretische Physik Astrophysik (Thielemann)
Item Type:Thesis
Thesis no:7350
Bibsysno:Link to catalogue
Number of Pages:88
Identification Number:
Last Modified:30 Jun 2016 10:41
Deposited On:13 Feb 2009 15:21

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