A white dwarf star has a temperature of 13000k. What is the probable luminosity of the star

The luminosity of an obejct is proportional to aera times temperature^4. but although temperature might be ten times as large as the temperature of the sun, a typical white awrf is about as big as the earth but white dwarfs are not so dull as thier reputaion makes them take the system 40 eridani it contains two main sequece stars and a white dwarfs the luminosity of the white dwarfs is greater than smaller of the sequence stars