August 11-15, 2014


Evidence of resonant mode coupling in the pulsating DB white dwarf star KIC 8626021

Weikai ZONG (Université de Toulouse, UPS-OMP/CNRS, IRAP)

Stéphane Charpinet (Université de Toulouse, UPS-OMP/CNRS, IRAP) and Gérard Vauclair (Université de Toulouse, UPS-OMP/CNRS, IRAP)

The Kepler spacecraft provides new opportinuties to observe long term frequency and amplitude modulations of oscillation modes in pulsating stars. We analyzed nearly two years of uninterrupted data obtained with this instrument on the DBV star KIC 8626021 and found clear signatures of nonlinear resonant mode coupling affecting several triplets. The behavior and timescales of these amplitude and frequency modulations show strong similarities with theoretical expectations. This may pave the way to new asteroseismic diagnostics, providing in particular ways to measure for the first time linear growth rates of pulsation modes in white dwarf stars.

Mode of presentation: poster