This is a Hubble Space Telescope image of the crowded core of the globular cluster, Omega Centauri.
The brilliant colors of the stars are real, they correspond to stellar temperatures. They can also be used to trace stellar evolution.
Astronomers like to know how blue the blue stars are and how red the red stars are.
We'll first sort these stars out by color blue on the left and red on the right.
Next we'll sort the stars according to brightness the brightest stars at the top and the faint stars at the bottom.
The final plot you see represents stages of evolution of stars
represents different stages of evolution of stars.
Stars spend most of their life time burning on the main sequence.
When the fuel starts to run out they expand to become red giants.
They find a new source of fuel --- Helium --- and burn blue hot, but even that runs out.
They end up burning out as white dwarfs.
Based on images for the Hubble Space, Telescope
we've assembled a true plot that is a snapshot of the life history of stars in this ancient cluster.