Citation
Liu, Yuk Tung (2003) Dynamical Stability of Nascent Neutron Stars. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:03112014101628149
Abstract
This thesis presents a study of the dynamical stability of nascent neutron stars resulting from the accretion induced collapse of rapidly rotating white dwarfs.
Chapter 2 and part of Chapter 3 study the equilibrium models for these neutron stars. They are constructed by assuming that the neutron stars have the same masses, angular momenta, and specific angular momentum distributions as the precollapse white dwarfs. If the precollapse white dwarf is rapidly rotating, the collapsed object will contain a high density central core of size about 20 km, surrounded by a massive accretion torus extending to hundreds of kilometers from the rotation axis. The ratio of the rotational kinetic energy to gravitational binding energy, β, of these neutron stars is all found to be less than 0.27.
Chapter 3 studies the dynamical stability of these neutron stars by numerically evolving the linearized hydrodynamical equations. A dynamical barmode instability is observed when the β of the star is greater than the critical value β_{d} ≈ 0.25. It is expected that the unstable mode will persist until a substantial amount of angular momentum is carried away by gravitational radiation. The detectability of these sources is studied and it is estimated that LIGO II is unlikely to detect them unless the event rate is greater than 10^{6}/year/galaxy.
All the calculations on the structure and stability of the neutron stars in Chapters 2 and 3 are carried out using Newtonian hydrodynamics and gravity. Chapter 4 studies the relativistic effects on the structure of these neutron stars. New techniques are developed and used to construct neutron star models to the first postNewtonian (1PN) order. The structures of the 1PN models are qualitatively similar to the corresponding Newtonian models, but the values of β are somewhat smaller. The maximum β for these 1PN neutron stars is found to be 0.24, which is 8% smaller than the Newtonian result (0.26). However, relativistic effects will also change the critical value β_{d}. A detailed postNewtonian stability analysis has yet to be carried out to study the relativistic effects on the dynamical stability of these neutron stars.
Item Type:  Thesis (Dissertation (Ph.D.))  

Subject Keywords:  Physics  
Degree Grantor:  California Institute of Technology  
Division:  Physics, Mathematics and Astronomy  
Major Option:  Physics  
Thesis Availability:  Public (worldwide access)  
Research Advisor(s): 
 
Group:  TAPIR  
Thesis Committee: 
 
Defense Date:  8 May 2002  
Funders: 
 
Record Number:  CaltechTHESIS:03112014101628149  
Persistent URL:  http://resolver.caltech.edu/CaltechTHESIS:03112014101628149  
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided.  
ID Code:  8122  
Collection:  CaltechTHESIS  
Deposited By:  Benjamin Perez  
Deposited On:  12 Mar 2014 16:28  
Last Modified:  28 Sep 2017 22:47 
Thesis Files

PDF
 Final Version
See Usage Policy. 22Mb 
Repository Staff Only: item control page