uh there are 2 types 1 gravity contained and fusion self sustained or 2 gravity generator in center wiht some heat source or self sustained

if u want it then use first type - do whol around hydrogen make it somehow self sustained fusion or use uranium and after hydrogen will turn into nble after co2 and after oxygen and maybe after it will turn into oxygen gas giant or black hole

it is oxygen fusion - oxygen fusion is last thing oh and also dont forget put ur star into ehole

It is not oxygen fusion.

man it is oxygen fusion oxygen fusion in game is happening at extreme gravity heat and pressure and creates bmetl and gravitones and neutrons hotter than 9999
info from tpt wiki 

When oxygen is over 9700°C in temperature, the pressure is over 250 and the gravitational force is over 20 in total, the oxygen fuses into broken metal. It will also release a neutron (with temperature over maximum), a photon (same temperature), a graviton and a particle of plasma (once again with same temperature).

It will also increase the temperature around the location to max temp (9726.85°C) and pressure to max pressure (256)

The oxygen's fusion is by far the most violent fusion in the whole game.

bruh