Print ViewBlackbody Radiation and Continuous Spectra

[Sasa888]

Homework Statement

An astronomer is trying to estimate the surface temperature of a star with a radius of 5.0* 10^8m by modeling it as an ideal blackbody. The astronomer has measured the intensity of radiation due to the star at a distance of 2.5* 10^{13}m and found it to be equal to 0.055 W/m^2. Given this information, what is the temperature of the surface of the star?

My attempt:

I tried using I(labda)= 2*pi*h*c² /labda^5*(e^(hc/labda*k*T)-1)
But ik keep getting stuck.. I don't know what to do with the radius of the star nor do i know what to do with the distance between the star and the measurement of I..

 

[Redbelly98]

Don't worry about the wavelength dependence. There's an equation for the total power-per-surface-area of a blackbody at temperature T. You can use that, plus the total surface area of the star, to get started.

 

[Sasa888]

Are you talking about:
P=4pir^2*s*T^4

Where s is the Stefan Bolzmann constant ??
Because now i don't know what to do with the distance given from th star to the place of the measurement..