The problem with Polaris is that no one can agree on how big or distant it is. Astrophysicists have a few ways to calculate the mass, age and distance of a star like Polaris. One method is a stellar evolution model...Researchers can study the brightness, color and rate of pulsation of the star and use that data to figure out how big and bright it is and what stage of life it's in. These models are especially precise for cepheids, because their rate of pulsing is directly related to their luminosity, or brightness. That makes it easy to calculate the...