Finding the Instability Strip for Accreting Pulsating White Dwarfs from HST and Optical Observations

TL;DR

This study uses ultraviolet and optical observations to determine the temperature range and pulsation characteristics of accreting white dwarfs, revealing a wider instability strip than previously known and complex pulsation behaviors.

Contribution

It establishes the temperature range of the instability strip for accreting pulsating white dwarfs and analyzes their pulsation properties across UV and optical wavelengths.

Findings

Instability strip ranges from 10,500-15,000K.

Pulsation amplitudes vary between UV and optical.

Some systems show no pulsations at certain wavelengths.

Abstract

Time-resolved low resolution Hubble Space Telescope ultraviolet spectra together with ground-based optical photometry and spectra are used to constrain the temperatures and pulsation properties of six cataclysmic variables containing pulsating white dwarfs. Combining our temperature determinations for the five pulsating white dwarfs that are several years past outburst with past results on six other systems shows that the instability strip for accreting pulsating white dwarfs ranges from 10,500-15,000K, a wider range than evident for ZZ Ceti pulsators. Analysis of the UV/optical pulsation properties reveals some puzzling aspects. While half the systems show high pulsation amplitudes in the UV compared to their optical counterparts, others show UV/optical amplitude ratios that are less than one or no pulsations at either wavelength region.