It wouldn't burn up upon entering the atmosphere, no. The atmosphere would, however, potmark the hull, and impact with the ground would serve to shatter the warship to pieces.
You two are forgetting about the energy shield protecting the planet. The energy shield would act as a brick wall, shattering the bow, and break off large pieces of the damaged stern before the shield would collapse, and provided that the reactor didn't go critical at this stage and exploded the ship into several large pieces, would probably go through the atmosphere as Ankhy described, and hit the surface as he described.
And how much damage would the impact cause to the world it's self? Were talking about a ten or eighteen long object, effectivley a small moon of an asteriod, hitting the surface at high speed. Imagine the groundquakes, tremors reaching 65 on the Rictor scale.
Well, yes, if it goes nose first. I was thinking it would go down belly first, why I don't know.
Kraken, I don't think it would hit a 65.. I believe on the Rictor scale each additional number is twice the power of the number previous. eg: a 4 is twice as powerful as a 3. A 65 would rip a planet to shreds.
Also, it would take quite an effort to move that much mass of metal up through the atmosphere. They would probaly have to dig tunnels under the epicenter, and attach repulsor coils like they did to Lusankya, then when it gets high enough, grab with with tons of tractor beams from a fleet of Star Destroyers or something like that. But if it fell into an ocean, that wouldn't be possible.
