In astronomy, a frozen star, besides a disused term for a black hole, is a hypothetical type of star that, according to the astronomers Fred Adams and Gregory P. Laughlin, may appear in the future of the Universe when the metallicity of the interstellar medium is several times the solar value.
Characteristics
Due to opacity effects, as metallicity of the interstellar gas increases both the maximum and minimum masses a star can have will decrease. For the latter case, it's expected that an object with a mass of 0.04 solar masses (40 times the mass of Jupiter), that currently would become a brown dwarf unable to fuse hydrogen, could do so ending in the main sequence with a surface temperature of 0 °C (273 K, thus frozen), much cooler than the dimmest red dwarfs of today, and water ice clouds forming in its atmosphere. The luminosity of these objects would be more than a thousand times lower than the faintest stars currently existing and their lifetimes would also be sensibly longer.