Delayed Q Branch White Dwarfs Lack Strong Magnetism
In February 2026, a manuscript led by graduate student and BUWD member Lou Baya Ould Rouis (Ould Rouis, Hermes, Guidry et al. 2026) was accepted which we hope will change the way we think about some white dwarf merger remnants. Ultramassive white dwarfs in the Gaia “Q branch” exhibit multi-Gyr cooling delays, likely linked to merger origins, but our volume-limited spectroscopic study within 100 pc reveals unexpected trends in composition and rotation of the most delayed Q branch white dwarfs. Contrary to expectations for merger products, the most delayed objects show little magnetism or rotational variability. We also add new detections of pulsations in DAQ white dwarfs which suggest a possible extension of the DAV instability strip to hotter, thin-hydrogen atmospheres. The manuscript has been accepted in The Astrophysical Journal.