Simulation of a red giant engulfing a hot Jupiter

Lau et al. "Hot Jupiter engulfment by a red giant in 3D hydrodynamics"
https://arxiv.org/abs/2210.15848

Simulation is of a 1 M_⊙, 4 R_⊙ engulfing a ~Jupiter size planet (the actual parameters are chosen to given an initial mass and radius ratios of 10^-3 and 2.5×10^-2 respectively).

Videos available at https://themikelau.github.io/planet_engulfment.html

Most of the planet's mass dissipates into the convective zone, with the lithium enhancement estimated at 0.13 dex. High rotational velocities seem to be confined to a small layer at the surface of the star, and there is the possibility for luminous transients:

Quote :

The orbital energy deposited via drag into the stellar envelope may produce a luminous transient, particularly for engulfment events occurring on the subgiant or lower part of the red giant branch. The small amount of unbound ejecta, ~10^-5 M_⊙ in our simulation, could give rise to a second, recombination-powered peak in the lightcurve that is ten times more luminous than the unperturbed star.