The shapes of light curves of Mira-type variables

TL;DR

This study analyzes 454 Mira variable star light curves from the ASAS survey, revealing that about 30% deviate significantly from sinusoidal shapes, with two main non-sinusoidal patterns and weak links to stellar parameters.

Contribution

It introduces a general approach to identify deviations from sinusoidal light curves and characterizes the diversity of Mira star light curve shapes.

Findings

30% of Mira light curves deviate from sinusoidal shape

Two characteristic non-sinusoidal light curve patterns identified

Weak correlation between light curve shape and stellar parameters

Abstract

Using a sample of 454 mira light curves from the ASAS survey we study the shape of the light variations in this kind of variable stars. Opposite to earlier studies, we choose a general approach to identify any deviation from a sinusoidal light change. We find that about 30% of the studied light curves show a significant deviation from the sinusoidal reference shape. Among these stars two characteristic light curve shapes of comparable frequency could be identified. Some hint for a connection between atmospheric chemistry and light curve shape was found, but beside that no or only very weak relations between light curve shape and other stellar parameters seem to exist.