Consider an old and a young population of stars with the colors given in the table. Compute the colors of different mixes of each, ranging from 100% young to 100% old. Plot the locus of the colors of the mixed population in a color-color diagram. For comparison, also plot the observed mean colors of galaxies from Huchra (1977, ApJS, 35, 171). Can you explain the observed variation of colors with this simple two component model? Comments on what this might mean.
|Old Pop||Young Pop|
For a simple single population like a globular cluster, compute and plot the fractional mass in the form of white dwarfs up to an age of 13 Gyr. Assume a Salpeter IMF with lower and upper mass limits of 0.1 and 100 solar masses. You may ignore the evolution of the total mass of the cluster due to gas ejection.