Stability of SN Ia progenitors against radial oscillations

Abstract

We analyze the possible existence of a pulsational instability excited by the $\epsilon$-mechanism during the last few centuries of evolution of a Chandrasekhar mass white dwarf prior to its explosion as a Type Ia supernova. Our analysis is motivated by the temperature sensitivity of the nuclear energy generation rate ($\sim T^{23}$) in a white dwarf whose structural adiabatic index is near 4/3. Based upon a linear stability analysis, we find that the fundamental mode and higher order radial modes are indeed unstable and that the fundamental mode has the shortest growth time scale. However, the growth time scale for such instability never becomes shorter than the evolutionary timescale. Therefore, even though the star \emph{is} pulsationally unstable, we do not expect these radial modes to have time to grow and to affect the structure and explosion properties of Type Ia supernovae.

arXiv comment15 pages, 4 figures, accepted for publication in ApJ

References in corpus (4)

• Type Ia Supernova Explosion Models
• Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications
• On the stability of very massive primordial stars
• Carbon Ignition in Type Ia Supernovae: An Analytic Model

Cited by in corpus (5)

• Nuclear fusion in dense matter: Reaction rate and carbon burning
• Carbon Ignition in Type Ia Supernovae: II. A Three-Dimensional Numerical Model
• Electron thermal conductivity owing to collisions between degenerate electrons
• The Deflagration Stage of Chandrasekhar Mass Models For Type Ia Supernovae: I. Early Evolution
• Type Ia Supernova Explosions from Hybrid Carbon-Oxygen-Neon White Dwarf Progenitors