  LP 40-365 (aka GD 492) is a nearby low-luminosity hyper-runaway star with an
extremely unusual atmospheric composition, which has been proposed as the
remnant of a white dwarf that survived a subluminous Type Ia supernova (SN Ia)
in a single-degenerate scenario. Adopting the Gaia Data Release (DR2) parallax,
1.58 +/- 0.03 mas, we estimate a radius of 0.18 +/- 0.01 Rsun, confirming LP
40-365 as a subluminous star that is ~ 15 times larger than a typical white
dwarf and is compatible with the SN Ia remnant scenario. We present an updated
kinematic analysis, making use of the Gaia parallax and proper motion, and
confirm that Lp 40-365 is leaving the Milky Way at about 1.5 times the escape
velocity of the Solar neighbourhood with a rest-frame velocity of 852 +/- 10
km/s. Integrating the past trajectories of LP 40-365, we confirm it crossed the
Galactic disc 5.0 +/- 0.3 Myr ago in the direction of Carina, likely coming
from beneath the plane. Finally, we estimate that LP 40-365 was ejected from
its progenitor binary with a velocity of at least 600 km/s, which is compatible
with theoretical predictions for close binaries containing a white dwarf and a
helium-star donor.
