Scientists share initial analysis of samples from asteroid Ryugu

[captaincranky]

What's your point

Oh the earth's core is hot well yes it is hot but that does not equate to the temperature of the outer surface where Asteroids hit
and since the majority of Asteroids are made of water ice only a very small part of it will actually impact on the surface the rest will simply be melted into the atmosphere on entry. Where it will remain as a gas until it condensates and falls to the ground as liquid water thereby cooling the heated surface of our planet even more and so on and so forth until such time as the earth's surface is cool enough for liquid water to remain pooled on the surface

We should probably end this discussion. You have you asteroid theory, and I'm not going to talk you out of it. As for any possibility I might have suggested, fuggeddaboutit

The flash point of hydrogen is 500 C. The melting point of iron is 1538 C. The byproduct of oxygen and hydrogen combustion is "oxygen hydride" which most of us call "water".