Astronomy 1021 Lecture : Stars
Document Summary
Things we want to know about every star: Because we cannot get close enough to stars to really measure the above we have to just work with what we can see from earth. Our snapshot of the stars in the milky way galaxy is based on what we can actually observe right now which are points of light which can be faint or bright. We see that measuring two quantities is enough for now and those are the luminosity (total energy output of stars) and the surface temperature of the stars. As we have seen for the sun the total energy (power) output is called luminosity which we abbreviate to l . For what follows generally energy output will be compared to the sun s (we use the unit solar luminosity (lsun)) Therefore two stars that have the same luminosity have the same total energy output and thus are producing the same amount of energy.