Non-Normal Pulsation

Department of Mathematical Sciences, Montclair State University, Montclair, NJ, USA

Abstract

Klein-Gordon operators with complex potentials are formulated as model systems to examine the possible impact of non-normality on the stellar pulsation eigenvalue problem. Computations of spectra, ε-pseudospectra and resolvent norms for these operators show that extended regions of complex potential, corresponding in stars to non-adiabatic regions, leads to strong non-normality. Introduction of an advective term further increases non-normal properties. Prospective model improvements and implications for resonances and for nonlinear pulsation are considered.