What do main sequence stars become giants or supergiants?

Main Sequence Stars, Giants, and Supergiants. First, let's look at how a star with the mass of the Sun might evolve. The four figures below illustrate what this star will look like in the phases of its evolution. read more

Stars with the mass of the Sun will last on the main sequence about 9 billion years. Very massive stars, like those in the Trapezium in Orion, will only last a million years or less. Low-mass stars can survive for tens of billions of years or more. Stars more massive than the Sun not only burn out more quickly, but they burn much hotter and brighter. read more

Main sequence stars become red giants do to a change in hydrostatic equilibrium. When a star is in hydrostatic equilibrium, the outward pressure of the nuclear reactions and the inward force of the star's own gravity. When the star runs out of fuel, it contracts. read more