  We searched the Gaia DR3 database for ultramassive white dwarfs with
kinematics consistent with having escaped the nearby Hyades open cluster,
identifying three such candidates. Two of these candidates have masses
estimated from Gaia photometry of approximately 1.1 solar masses; their status
as products of single stellar evolution that have escaped the cluster was
deemed too questionable for immediate follow-up analysis. The remaining
candidate has an expected mass >1.3 solar masses, significantly reducing the
probability of it being an interloper. Analysis of follow-up Gemini GMOS
spectroscopy for this source reveals a non-magnetized hydrogen atmosphere white
dwarf with a mass and age consistent with having formed from a single star.
Assuming a single-stellar evolution formation channel, we estimate a 97.8%
chance that the candidate is a true escapee from the Hyades. With a determined
mass of 1.317 solar masses, this is potentially the most massive known
single-evolution white dwarf and is by far the most massive with a strong
association with an open cluster.
