I think this would be a very interesting item. Now the picture below is just a crude MS paint version, so don't be too harsh. So basically it would be a small star attached to a handle, and contained by some sort of energy field. Maybe you can travel to a dying sun and somehow find this mini-star near(or inside) the sun. then you could craft the finished product.
The picture is quite crude, but then again, I'm no artist, so who am I to judge? Anyway, on to the actual suggestion. I think since it's harnessing a freaking star, it should be pretty powerful, and set things on fire. That is all.
I've actually thought about suggesting things like this to other games, so I quite like it. I would suggest making it a neutron star, which would partially explain the size, but any star would work.
But perhaps the weapons energy field around it makes it as light as a bowling ball, giving the player the ability to use it
Aren't all stars? Yes, neutron stars are some of the densest things outside of a black hole, but if you have the tech to make stars wield-able, you can do the same for a neutron star. Some anti-gravity device to partially counteract the weight, but not altering the mass, which would give you a controllable superdense/super heated weapon.
This is really good. Maybe the technology responsible for holding the mini-star in place weakens it somehow. Therefore this weapon wouldn't an godmode item.
But of course! Thinking about my solution, anti-gravity would greatly lessen it's inertia, making it easier to stop and therefor (greatly) lowering it's power. Hopefully they keep all god mode items out of Starbound. I'm looking at you, Star cannon, Flamelash, Megashark, and Magical Harp.
Well certainty no godmode weapons would be great, but there definitely should be very powerful weapons, the game take place across endless amount of planets, and there will be deadly creatures that you may not want to spend so much time fighting later in the game.
i think it'd be a pretty cool idea, although as has been stated/hinted at: it should be a later-game type weapon you can acquire or perhaps a star happens to explode/implode, sending bits of it self over multiple/random planets and you gather "star shards/ bit of exploded star/ idk what to call it" to create a star flail