Dwarf star
In astronomy, a dwarf star is generally understood to mean a main sequence star . Main sequence stars are by far the most numerous stars . Unlike other stars, main sequence stars release their energy through the fusion of hydrogen in the stellar core. Non-main sequence stars, on the other hand, are developed stars whose hydrogen supply in the core is exhausted. The term dwarf is relative to other stars of the same spectral type , but higher luminosity class ( giant stars ).
Other stellar and substellar objects in astronomy have “dwarf” in their name, but are not main sequence stars and are therefore not counted among the actual dwarf stars:
White dwarfs are stars in which nuclear fusion has ceased and which heat up to 100,000 K under the pressure of gravity. They have a diameter of 7,000 to 14,000 km.
In the further course, a white dwarf cools down and becomes fainter until it has possibly become a black dwarf . These objects are so far hypothetical, i. that is, no representative was observed.
Brown dwarfs are substellar objects that form like stars from dense molecular clouds , but do not achieve the necessary mass to ignite the hydrogen fusion in the core. However, you can start with the lithium fusion and the deuterium fusion.