Rapid Variability in the Wind from the White Dwarf Merger Candidate J005311

TL;DR

This study investigates rapid spectral variability in the white dwarf merger candidate J005311, revealing fast-moving wind clumps and confirming a predicted emission feature, thus shedding light on its unique stellar wind properties.

Contribution

It provides the first detailed analysis of spectral variability in J005311, confirming a predicted emission feature and revealing extremely rapid wind clump motions.

Findings

Detection of a broad emission feature at 343nm matching models.

Observation of highly variable OVI emission line profiles.

Subpeaks in wind profiles can move up to 16000 km/s in less than two hours.

Abstract

We analyze time-series spectroscopy of the white dwarf merger candidate J005311 and confirm the unique nature of its optical spectrum. We detect an additional broad emission feature peaking at 343nm that was predicted in the Gvaramadze et al. (2019; arXiv:1904.00012) models. Comparing ten spectra taken with the Large Binocular Telescope (LBT), we find significant variability in the profile of the strong OVI 381.1/383.4nm emission feature. This appears to be caused by rapidly shifting subpeaks generated by clumpiness in the stellar wind of J005311. This line variability is similar to what is seen in many Wolf-Rayet stars. However, in J005311, the rate of motion of the subpeaks appears exceedingly high as they can reach 16000 km/s in less than two hours.