So I found the base of these pesky rebels on this planet and I am tasked with destroying the planet to eliminate the rebels once and for all. Unfortunately, my death star has malfunctioned and has been rendered totally inoperable.
Now, all I have is effectively an unlimited supply of antimatter (which is contained within a permanent magnetosphere within the core of the death star), but no weapon by which to use it and no matter by which to retrieve it without building something.
I can harvest the parts from the death star (which my boss built as an actual clone of the death star from the Galactic Empire from a different universe; but that's another story) but due to the critical failure of the project since my boss obviously had no idea what he was doing when he built this thing, there are no electronic parts and there is no way to actually use any electronic parts, weapons, or any other electrical equipment.
Since there are no electronics, we are also stranded here in space hanging above this planet. I have to destroy this planet before my boss arrives because he's surely to blame it all on me, and also there is a risk those rebels will blow us up too if we don't get them first.
Unlike the other universe which we don't actually have access to, our universe has no magical [force]es, so I can only use science and the laws of physics. I have no process for which to manufacture silicone or any comparable material for electronics, so no electronics are available and no way to make any electronics.
However, there is a fully mechanical particle accelerator on board which is still functional (it's an advanced futuristic prototype requiring no electricity, around the circumference of the death star); as well as plenty of chemicals of every type, so chemical reactions are also possible. But the failure prevented any electronics and there is a permanent gravity EMP surrounding the death star caused by the failure, preventing any electronics from working or flying.
Keep in mind we can't deliver a physical payload since the rebels will see it coming and we have no force field to protect us, they'll kill us before we shoot anything at them. Gravity wells? Black holes? We need a way to covertly destroy the planet without shooting anything at them.
How can I destroy this planet and eradicate these rebels once and for all using my antimatter and any harvested materials or mechanics from this death star replica?