Modelling Long-Period Variables -- II. Fundamental mode pulsation in the nonlinear regime

Understand

Long-period variability in luminous red giants has several promising applications, all of which require models able to accurately predict pulsation periods.

• Linear pulsation models have proven successful in reproducing the observed periods of overtone modes in evolved red giants, but they fail to accurately predict their fundamental mode periods.
• Here, we use a 1D hydrodynamic code to investigate the long-period variability of M-type asymptotic giant branch stars in the nonlinear regime.
• We examine the period and stability of low-order radial pulsation modes as a function of mass and radius, and find overtone mode periods in complete agreement with predictions from linear pulsation models.