What is the end state of a star?

Answer 1

The general term for the end state of a star is a stellar remnant - which might take one of several forms depending mostly on the mass of the star. A typical main sequence star below about ten solar masses might end its life as a white dwarf and cool to the brown stage and (eventually) become a black dwarf. Heavier stars may shed much of their outer envelope into a planetary nebula, and their remnant might be a neutron star (or pulsar); even heavier and it might become a more exotic form of collapsed matter, or become a black hole - these remnants believed to be preceded by the violent explosion of the massive star in a supernova.

In all these cases, the stellar furnace is out, but the mass lives on. Interestingly enough, because of the presence of elements in our sun in trace amounts that aren't formed by ordinary stellar fusion processes, likely it is "second generation" or more - elements having accumulated into a new star from previous supernova explosions thought to be the only means of creation of elements heavier than iron. The same is true of terrestrial matter - we are believed to be made of material which was once present inside a star.