Two New Variable Hot DQ Stars

TL;DR

This paper reports the discovery of two new variable hot DQ white dwarf stars, confirming a new class of variable white dwarfs with unique pulsation characteristics, expanding our understanding of stellar variability.

Contribution

It introduces two newly identified variable hot DQ stars, providing evidence for a distinct class of variable white dwarfs with unique pulsation properties.

Findings

Discovered two new variable hot DQ stars from SDSS data.

Confirmed the existence of a new class of variable white dwarfs.

Observed that their pulsation amplitudes are smaller than the first known hot DQ variable.

Abstract

We have discovered periodic variations in the light curves of two hot DQ stars from the Sloan Digital Sky Survey, SDSS J220029.08-074121.5 and SDSS J234843.30-094245.3. These are the second and third variables detected among the hot DQs and confirm the existence of a new class of variable white dwarf stars. The amplitudes of the variations are one half as large as those detected in the first discovered variable, SDSS J142625.71+575218.3, and required high signal-to-noise photometry to detect. The pulse shapes of the stars are not like those of known white dwarf pulsators but are similar to the first hot DQ variable, SDSS J142625.71+575218.3.