How intermediate-mass stars evolve
Intermediate-mass stars consume their fuel faster than low-mass stars over a time period of around 10 billion years (the Sun is an intermediate mass star). When their hydrogen gets used up their core collapses. As the core contracts, the temperature increases and the outer layers expand and cool. At this stage the star is now a red giant. As time progresses the outer layers will evaporate off until a white dwarf is left.