Post-Planetary Nebulae and "Iron Dwarf" stars.

[daniel l.]

I have lately been imagining what would happen if a massive explosion blew off the outer layers of Neptune's atmosphere. This would leave a white hot glowing core, And a surrounding nebula. Would enough radiation be emitted from the "Star" to melt the ice on Triton and generate an atmosphere and making terraforming possible. Also how hot would that "Star" be and how long would it last before cooling?

[kerbiloid]

That would be not a star, but a hot steam cloud which would then mostly condensate and rain back onto the Neptune.
Triton would be probably damaged and its orbit would be definitely affected at least by the drag force of this cloud. As it's already near the Roche limit, it would be probably teared apart by tidal forces and make a dense ring system which would fall down onto the Neptune too several millenia later.
Afaik, the last planet where the greenhouse effect can keep more or less decorous temperature conditions is Saturn.

[daniel l.]

1 hour ago, kerbiloid said:

That would be not a star, but a hot steam cloud which would then mostly condensate and rain back onto the Neptune.
Triton would be probably damaged and its orbit would be definitely affected at least by the drag force of this cloud. As it's already near the Roche limit, it would be probably teared apart by tidal forces and make a dense ring system which would fall down onto the Neptune too several millenia later.
Afaik, the last planet where the greenhouse effect can keep more or less decorous temperature conditions is Saturn.

I was referring to the core as a "Star" it was my assumption that if the gaseous outer layers were blown out into space with over 75% of it becoming orbital, And hopefully far enough off the ecliptic to prevent an intensified orbital decay. And it was my opinion that a super hot ball of iron roughly the size of Earth would radiate a lot of heat and take at least several million years to cool. Which would warm any moons and provide terraforming opportunities. And while i dont doubt that Triton would definitely be damaged by the explosion, Perhaps the sudden loss of Neptunian mass would increase the SemimajorAxis of Triton.

[kerbiloid]

59 minutes ago, daniel l. said:

Perhaps the sudden loss of Neptunian mass would increase the SemimajorAxis of Triton.

Most of the gas thrown away will stay on low orbit (inside the Triton's orbital sphere), so the gravitational mass will not significantly decrease.