"Why are you waking me up Sergeant? And why did we enter near-light speed?"
"We received a distress call, and there wasn't enough time to notify you, sir."
"What kind of distress signal?"
"It came from System 235. It was jammed before we could get much out of it, sir."
"How long til we reach them?"
"1000000 years, universe time, sir."
"No man, local time."
"Given our Lorentz factor of about 9000000000, about an hour, sir."
"Is that enough time to prepare?"
"Given that we have no idea to the nature of the emergency, and that we lost communication, we are as ready as we will ever be."
1000000 years universe time. All sorts of things could have in that amount of time. If he remembered his Lorentz tables correctly, System 235's standard time runs on a Lorentz factor of 4500000000, so it will take about 2 hours of their time for them to get there. Nothing they could do about that though. They were already within 1% of the speed of light, and at that speed, it would take 2 hours of their time, regardless of their the ship's Lorentz factor.
Just then, they arrived. The ship pulled into the photon sphere of a docking black hole. "Scan the system, private."
"Yes, sir. Sir, the sun!"
"What man. Spit it out."
"The sun, is gone! It has collapsed into a black hole! All the planets are frozen, trillions dead!"
That star wasn't scheduled to collapse in such a short time. In fact, it wasn't supposed to collapse at all, it was supposed to become a white dwarf. "What happened!"
"I have no idea sir!"
"I may have an idea!"
"I think. THEY may have broke, the treaty, uh, sir."
End Useless Backstory
So, THEY have broke the treaty, as far as our intel can show. THEY have created a CrushSun, a starship capable of destroying moons, planets, and, mainly, suns. It works via the following principle:
- The ship is spherical. It shoots a bunch of lasers toward the center, creating a black hole. See this (page 9). (How the micro black hole is created isn't important, just as long as it is created.)
- When the black hole is at the right mass, the lasers are turned off, except one. It shoots the black hole out of a hole in the ship. The laser looks terrifying, but it is the black hole which destroys the system's sun, by crushing it.
My question is, how big and how much energy must such a device use? Use the link above as a starting point. (Considering the locomotion of the ship is optional.)
NOTE: Although a lot of hard science has been done on a similar device, which serves the same purpose, they are completely different designs. The death star needs to overcome the gravitational binding of energy of the target, whereas for this the target doesn't matter (cubic v.s. constant, with respect to scale). You can use that information roughly, but keep in mind that these devices are different.
BONUS: How much waste heat would it produce, and what kind of exhaust ports would be necessary?