Red giant stars are much smaller and much less massive than red supergiant stars.Most red giant stars live up to around 0.1 to 2 billion years.Red giant stars are between 100 to 1.000 times more luminous than our Sun.All stars die when they burn up all their fuel and there is no more pressure to keep gravity pushing towards their centers.Red giant stars no longer perform nuclear fusion between helium and hydrogen in their cores and thus they heat up and expand several times their previous size.Most of the well-known bright stars are red giants, due to their luminosity and because they are moderately common.Red giant stars differ in a way by which they generate energy.

Red giant stars usually result from low and intermediate-mass main-sequence stars of around 0.5 to 5 solar masses.A red giant star is a dying star in the last stages of its stellar evolution.A red giant star’s appearance is usually from yellow-orange to red, including the spectral types K and M, but also S class stars and carbon stars.

Chromatic displacement red giant