Planetary core
A planetary core or simply core was the innermost layer at the center of a planet or an asteroid, in the same way that a stellar core was the center of a star. 

The core was divided into an outer core and an inner core. ()

M-class planets had a nickel-iron core. ()

In 2258 of the alternate reality, Nero used a mining drill on the Narada to dig to the core of . He then put red matter into the core of Vulcan, creating a black hole and destroying the planet. ()

The planet Terra 10 had a molten core surrounded by a mantle and crust that were entirely crystalline. ()

In 2285, Hikaru Sulu reported that ' core was unstable. ()

The gas giant Tethys III had a frozen helium core. ()

In 2368, an asteroid which threatened Tessen III with planetwide destruction had a core of nitrium and chrondite. ()

The moon Jeraddo around Bajor had a molten core, and in 2369, there were plans to transfer energy from this core, forcing the evacuation of the residents. ()

External link
 

de:Planetenkern
Geology