Stars<span> are </span>classified<span> by their spectra (the elements that they absorb) and their temperature. There are seven main types of </span>stars. In order of decreasing temperature, O, B, A, F, G, K, and M. Type O stars are the stars with the highest temperature and biggest luminosity. So, if there is a <span>new born star cluster : 1. with one O star, 2. with 10 A stars, 3. with 10 G stars, 4. with 1000 M stars
</span><span>the stellar type O will dominate the light output from the cluster.</span>
