"and so a star like the Sun could disrupt a planet of similar mean density only if the planet grazes the star’s surface."

Wouldn't it actually be the other way around? The star would go Nova if it was grazed by a planet?

At the Exploratorium in San Francisco, I saw the following exhibit:

A cylinder filled with water and silver slivers. The visitor could spin the cylinder, and then stop the cylinder. Naturally, the whirlpool of water that was started up inside would continue to spin, slowing down over time.

Long before the whirlpool had stopped spinning, all silver slivers were collected in the center. Two actions are at play:

1. The whirlpool collected all silver slivers one by one in the center of the whirlpool once the whirlpool had slowed down enough for a 'dead zone' to occur in the center. The center is of course without any churning action but only when the whirlpool slows down, only then is the ‘dead zone’ large enough to ‘capture’ the slivers.

2. Earth's gravity pulled the silver slivers down in a heap on the bottom.

As such, we can see how the Sun is not just based on gravity but also on the 'dead zone' action of the whirlpool that the proto Solar System used to be (and to a large extent still is).

--

The planet will be a greater canon ball to the star therefore than the star will be to the planet. Indeed, the Sun is mainly hydrogen and helium, so the lighter materials collect themselves in the 'dead zone' first. Gravity alone does not tell the entire story.

Let's see how this works for a planet by looking at the cylinder once more. This time, there are two kinds of silver slivers: flattened and rounded. The flattened slivers are caught by the 'dead zone' faster than the rounded slivers, so the heap at the bottom of the cylinder will end up being organized.

Same for planet Earth. The lighter materials got caught in the 'dead zone' first, before the heavier parts would get trapped. The lighter materials end up having some gravity of their own, and we see therefore a nice interplay between whirlpool's collection center and a building up of gravity in that spot.

Then, once planet Earth received all its materials, the planet reorganizes itself. Outgassing, for instance, is a quick way to see that lighter materials transported toward the surface and heavier metals toward the center of the planet.

Planet Earth is therefore different today than it was before, whereas the Sun with its lighter materials, almost all of the same kind, is far more like its original state.

--

Back to the cylinder at the exhibition. Once the heap of slivers is established, a new visitor can crank up the cylinder and the increasing speed of the whirlpool picks up the silver slivers from the bottom and they end up twirling along with the whirlpool again. This is very easy to do.

So, when the Sun encounters a close-by object, there is a good chance the stability of the environment is disturbed and sparks may actually fly away from the Sun.

The reality of the outer layers of the Sun (the actual Sun and not its volatile, switchback and beyond area), that is the question. How will that energy stuck in the ‘dead zone’ and at extreme pressures, how will that energy react to a planet or other object scraping the star? The outer layer’s reality is the big question.

—

Yellowstone geysers, for instance, erupt not when the entire system underneath boils. Rather, just the surface of the entire underground water system needs to reach boiling stage for the geyser to erupt.

Underneath, the temperature is already higher than boiling stage in most spots, but as long as the top layer of the geyser is below boiling stage the entire geyser will wait and not erupt.

If the Sun is indeed the collection of light materials in the 'dead zone' of the Solar System's whirlpool, then it does not matter that gravity and pressure are enormous for this globe because the real feature of our Sun is its stability that was established, and the solar materials' inability to escape from the 'dead zone'.

Any object that gets inside the ‘dead zone’ can add energy to the dead-calm reality and this could cause the Sun to go Nova. Most material simply does not make it to the actual Sun itself, it is burnt up long before reaching the star. It would be interesting to see what happens when something does make it to the Sun. That is, as long as the Sun does not go Nova, because we would not survive that ordeal.