Question

Sirius B is a white star that has a surface temperature (in kelvins) that is four times that of our sun. Sirius B radiates only 0.040 times the power radiated by the sun. Our sun has a radius of 6.96 108 m. Assuming that Sirius B has the same emissivity as the sun, find the radius of Sirius B. RsB =

Answer 1

Power (Radiatiation =eo energy emitted per sew cond) is THA We have TB=ATS &B=0.040&s = ) (eo T A 0.04 dec TPA) В S 4 4 =) AB TB 0.040 AST S 4. AB To 0.040 As T RB - 0.040 TRS 2 Ts TB 2 4 RB 0.040 ( ) Rs 2 1 RB Rs 0.2 RB = 0.0125 Rs we have RST 6.96x100 m Ro 0.0125 x 6.96x 100 m RB = 8.7 x 106m