Eggshell

From last Tuesday, the eggshell planet. That's a planet with a small lithosphere, defined as the nonviscous (brittle) crust plus outer-mantle.

As having smaller lithospheres I am interested (lately) into how they factor into the mantle rocks we see in defunct A and F systems. Planets as are not in A and F systems (on up) could be old; too old for an eggshell. If far from the star, also - no shell. And small Marslikes won't have a shell either. I don't see how any of these "pollute" the inevitable white dwarf.

So I take further away that the A and F pollutants were mostly eggshells, potentially anyway. That is: we do not see lithosphere in those pollutants, only asthenosphere. Of course it's all too late now for them.

The study is "The Effects of Planetary and Stellar Parameters on Brittle Lithospheric Thickness", doi 10.1029/2021JE006952. The various pressers tease that three not-dead-yet exoplanets are candidates. Implicitly our own good Earth is NOT an eggshell: our crust is famously shallow although I am less sure about our mantle.