structural:reformatting
An exotic star is a hypothetical compact star composed of exotic matter, and balanced against gravitational collapse by degeneracy pressure or other quantum properties. Types of exotic stars include quark stars
strange stars
§ Preon stars. Of the various types of exotic star proposed, the most well evidenced and understood is the quark star, although its existence is not confirmed. In Newtonian mechanics, objects dense enough to trap any emitted light are called dark stars,, as opposed to black holes in general relativity.
However, the same name is used for hypothetical ancient "stars" which derived energy from dark matter. Exotic stars are largely hypothetical – partly because it is difficult to test in detail how such forms of matter may behave, and partly because prior to the fledgling technology of gravitational-wave astronomy, there was no satisfactory means of detecting compact astrophysical objects that do not radiate either electromagnetically or through known particles. While candidate objects are occasionally identified based on indirect evidence, it is not yet possible to distinguish their observational signatures from those of known objects.