I'm trying to design a device that would cause a supernova in a high mass star. I want some kind of explanation so the device doesn't seem so handwavy. Is there any way to somehow increase the amount of Fe 56 or 58 in a star, increase the density of it's core, or increase the outward pressure on the star to rapidly accelerate the fusion cycle in high mass stars?
In order for a star to supernova, based on our current understanding of physics, you need to have three things:
- Sufficient mass for the start to explode rather than burn down (Roughly 6-8 times the mass of our own Sun
- An exhaustion or significant decrease of readily consumable fusion fuel
- Sufficient fuel of a different type such that the star is fusing heavier elements (think silicon rather than helium or nitrogen)
All of these things tend to occur over millions of years for stars of sufficient volume and mass. Additionally, there is still ongoing research in the field of supernovas, so there is not exactly a precise recipe to create one.
That said, it looks from the comment section that by "rapidly" you are talking hours, which is unfortunate. On a longer, stellar scale of "rapidly" (A few decades to a few centuries) it might be possible to trigger this effect by a reverse form of Star Lifting (https://en.wikipedia.org/wiki/Star_lifting). In a nutshell, instead of lifting or blasting mass out of the star, you would add massive amounts of heavy elements (probably multiple planet-sized lumps of iron or some such material) into the star at a velocity less than that of the escape velocity of the gravity well. The perk of this method is that it would be achievable at our currently level of technology and is compatible with current physics.
If you want to speed things up, you could greatly increase the mass you introduced. In theory, if you took two high-mass stars that were close to supernova anyway and smashed them into each other, the resulting collection of stellar mass would more rapidly burn through the fuel and supernova. The problems with this are A) moving a star and B) the physics of aiming that precisely in a moving universe so the mass doesn't just spiral off.
Finally, if you have access to some handwavium, you could teleport the core out of a star and replace it with supercritical fissile material. Supernovas occur when the gravity holding a star together is less than the force being expelled from the interior. By essentially detonating a super-nuke in the middle of a low-gravity space, you would get an impressive explosion. Strictly speaking, this would be less a supernova and more of a space nuke targeting a star.
You will need ridonkulous amounts of energy, or some handwavium.
So make your device out of believable handwavium.
Your device briefly, for about a minute, suppresses thermonuclear reactions within its field of effect. It was originally designed as a last-ditch shield to protect your fleet heavy battlecruisers against incoming hydrogen bombs, by suppressing their fusion reaction for the moment as they would detonate. How? I have no clue, that's for the technical boffins to know. We just activate the mechanism and hope we got the timing right. It is very large, very clumsy and takes days to reset, of course.
You, in your insane genius, have figured out that if you turn this device on a large star, it will very briefly stop the fusion process in the core, triggering a core collapse, and subsequent supernova runaway reaction.
You make very, very sure to not tell anyone this, as it would of course lead to you becoming the #1 most wanted fugitive in the known universe!