Basic Information
A Boson Star is a hypothetical huge star-like body composed of a hypothetical type of Boson called Axions. Axions don't interact with light, making them a cold dark matter candidate. Theoretically, if they prove to be numerous, boson stars could be a big chunk of the dark matter in the universe, and its possible some or all active galaxies may have a huge boson star at its active galactic core.
Now, the term "star" is kind of misleading in this context, as the Axions would not emit light or heat. So they might be something more like a giant invisible planet, or, more interestingly, they may form a superfluid Bose-Einstein condensate, and essentially function as if the entire celestial body were a single giant atom just barely above absolute zero temperature.
The axions that make up the boson star would be invisible and transparent, but it's possible they may very rarely decay into photons and emitting a bit of light or radiation. Under the right circumstances, this could even be a possible explanation for the fast radio burst phenomenon.
It's also possible or even likely that a small amount of normal matter would from time to time be caught in a boson star's gravity. This normal matter would fall inward to be crushed, and may emit light in the process. So it's possible that a boson star might have a visible component that glows and radiates near its core, surrounded by an invisible boson shell. If this is the case, it may look superficially like a small dim normal star, but exhibit the gravity of the much larger object it truly is. However, some models suggest that rotating boson stars may actually have a shape more like a donut or torus than a sphere. The internal glowing matter component might likewise have an unusual shape, or be an external glowing donut wrapped around an invisible core.
Sources
Game and Story Use
- A cluster of invisible boson stars could be like something of a minefield in space. Difficult to detect, and terribly dangerous to navigate the interstellar terrain.
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- PCs are cruising through a region of space that hasn't been well vetted/documented/explored. Helm control is set on autopilot, but they will eventually notice they are going way off course. Turns out they've wandered into the gravity well of an invisible bosun star, and while it wasn't enough to trap them in an unwanted orbit, or cause a collision, it did knock them off course. Correcting for the new velocity will add days to their journey, waste fuel or reaction mass, etc. It might also bring them closer to some sort of hidden subplot/location that the GM plans to use to introduce a new threat.
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- A boson star could be quite misleading or mysterious, due to its invisibility or partial invisibility. It might be mistaken for black hole or a smaller normal star. So it's probably a good match for a game about exploration or mystery in space. It's probably somewhat less interesting if the PCs have really good detection technology onboard their spacecraft, and/or the setting assumes a well-traveled and well-documented cosmos. I suspect it might go over better in a space opera than in hard sci-fi, but I could be wrong.
- The boson star itself might make a good negative space wedgie or swirly energy thingy.
- It might be interesting to feature a boson star as one half a binary star system, paired with a more traditional HabStar that provides all the life-sustaining energy needed. This may be especially true of a donut-shaped boson star with a wispy corona of fiery gases caught in its gravity, because it gives you an interesting visual to make the system memorable.
- It may be that a larger boson body is slowly consuming its smaller stellar partner, siphoning off an accretion disk or stellar wind, and thereby gradually increasing the ratio of normal matter to axions within the boson star.
- A boson star may be the home system for a very unusual lifeform, such as one also made of dark matter, or that doesn't need heat/light/energy for its life cycle. Some sort of starfish alien, or eldritch abomination that's based on hypothetical types of biochemistry and just entirely unlike life as we know it.
- There could be a lot of boson stars concealed in the dark matter halo at the outer edge of the milky way galaxy. This could be useful if you're telling a story set against the edge of the galaxy, like that classic Star Trek episode about how people are transformed by contact with the barrier at end of the galaxy. This could also work if your tale has space invaders, but you wish to be initially ambiguous about whether they are from another galaxy, another dimension, or maybe somewhere a little closer to home.