Light Curve Patterns and Seismology of a White Dwarf with Complex Pulsation

TL;DR

This study analyzes the pulsation patterns of the ZZ Ceti star KUV 02464+3239, revealing specific periods, model fits for its mass and hydrogen layer, and emphasizing the role of non-linear effects in its light curve variations.

Contribution

It provides the first detailed seismological analysis of KUV 02464+3239, identifying its pulsation periods and modeling its internal structure with emphasis on non-linear pulsation effects.

Findings

Six pulsation periods between 619 and 1250 seconds identified.

Acceptable stellar models have masses between 0.60 and 0.70 M_Sun.

Non-linear effects significantly influence the light curve shape.

Abstract

The ZZ Ceti star KUV 02464+3239 was observed over a whole season at the mountain station of Konkoly Observatory. A rigorous frequency analysis revealed 6 certain periods between 619 and 1250 seconds, with no shorter period modes present. We use the observed periods, published effective temperature and surface gravity, along with the model grid code of Bischoff-Kim, Montgomery and Winget (2008) to perform a seismological analysis. We find acceptable model fits with masses between 0.60 and 0.70 M_Sun. The hydrogen layer mass of the acceptable models are almost always between 10^-4 and 10^-6 M_*. In addition to our seismological results, we also show our analysis of individual light curve segments. Considering the non-sinusoidal shape of the light curve and the Fourier spectra of segments showing large amplitude variations, the importance of non-linear effects in the pulsation is clearly seen.