How are L, T, and R related?
	L = area T4 = 4  R2 T4 – Stars can be intrinsically bright because of either large R or large T – Use ratio equations to simplify above equation • (Note book’s symbol for Sun is circle with dot inside) – Example:  Assume T is different but size is same • A star is ~ 2  as hot as sun, expect L is 24 = 16 times as bright • M star is ~1/2 as hot as sun, expect L is 2-4 = 1/16 as bright • B star is ~  4  as hot as sun, expect L is 44 = 256 times as bright – Example:  Assume T same but size is different • If a G star 4  as large as sun, expect L would be 42=16 times as bright