Evidence of amplitude modulation due to Resonant Mode Coupling in the delta Scuti star KIC5892969

TL;DR

This study analyzes amplitude modulation in the delta Scuti star KIC5892969 observed by Kepler, providing evidence that resonant mode coupling may limit mode amplitudes and influence stellar pulsation behavior.

Contribution

It demonstrates that resonant mode coupling explains amplitude variations in KIC5892969, highlighting its role in delta Scuti star pulsation dynamics.

Findings

Resonant mode coupling is consistent with observed amplitude modulation.

Amplitude variations are linked to interactions between unstable and stable modes.

Resonant mode coupling may be a common amplitude limitation mechanism in delta Scuti stars.

Abstract

A study of the star KIC5892969 observed by the Kepler satellite is presented. Its three highest amplitude modes present a strong amplitude modulation. The aim of this work is to investigate amplitude variations in this star and their possible cause. Using the 4 years-long observations available, we obtained the frequency content of the full light curve. Then, we studied the amplitude and phase variations with time using shorter time stamps. The results obtained are compared with the predicted ones for resonant mode coupling of an unstable mode with lower frequency stable modes. Our conclusion is that resonant mode coupling is consistent as an amplitude limitation mechanism in several modes of KIC5892969 and we discuss to which extent it might play an important role for other delta Scuti stars.