Small Disturbances such a tiny bombs, small amounts of Thermite, etc, can cause the entire planet to collapse.
It becomes very difficult to "Extinguish" the so called star afterward.
Note: This save is based off of an older save that I created that is a sort of "Automatic Star" creator of sorts. Not really realistic though... Anyhow, due to that, this functions in a very similar way. Since Lava generates pressure, once the core collapses, it in turn causes the Uranium to heat up, which heats up the elements and leads to a loop