Resonant Mode Coupling in δ Scuti Stars by Mohammed Mourabit et al. on Wednesday 30 November

Delta Scuti ($\delta$ Sct) variables are intermediate mass stars that lie at

the intersection of the main sequence and the instability strip on the

Hertzsprung-Russel diagram. Various lines of evidence indicate that nonlinear

mode interactions shape their oscillation spectra, including the particularly

compelling detection of resonantly interacting mode triplets in the $\delta$

Sct star KIC 8054146. Motivated by these observations, we use the theory of

three-mode coupling to study the strength and prevalence of nonlinear mode

interactions in fourteen $\delta$ Sct models that span the instability strip.

For each model, we calculate the frequency detunings and nonlinear coupling

strengths of $\sim 10^4$ unique combinations of mode triplets. We find that all

the models contain at least $\sim 100$ well-coupled triplets whose detunings

and coupling strengths are consistent with the triplets identified in KIC

8054146. Our results suggest that resonant mode interactions can be significant

in $\delta$ Sct stars and may explain why many exhibit rapid changes in

amplitude and oscillation period.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15898v1