Vega in the constellation Lyra

 

Vega is well known for being a bright star so I was wondering why. It turns out that it is very close at only 25 light years which explains a lot about the brightness. But it is twice as heavy as the sun so that means it burns though its fuel faster and is hotter, a class A star. These hotter stars have much shorter lives; I was amazed to discover that it was only "born" during our Cambrian period. Using data from here, it is have roughly twice the radius of the Sun, so it has 4x the surface area. The temperature is roughly 1.7x. By Stefan's Law, that would mean the luminosity is 4 x 1.7 = 33x more luminous. The data gives 40x but there are quite large ranges in the radius and temperature data.