The bright star altair in the constellation of Aquila (the eagle) has a surface temperature of 7400K. By?

comparison, the surface tempertaure of the sun is 5779K. Relative to the sun how much more energy is emitted per second from each square metre of altairs surface?The bright star altair in the constellation of Aquila (the eagle) has a surface temperature of 7400K. By?Using the Stefan-Boltzmann Law:



L = (4蟺R^2)蟽T^4



L = luminosity or total energy output

R = radius and (4 pi R^2)

蟽 = Stefan-Boltzmann constant

T = surface temperature (in Kelvin)



Hence, the energy flux or energy output per unit area per unit time is



桅 = L/(4蟺R^2) = 蟽T^4



蟽 = 5.67 x 10^-8 J K^-4 m^-2 sec^-1



Therefore,



螖桅= 桅(Altair) - 桅(Sun) = 蟽(T^4(Altair) - T^4(Sun))



= 1.0678 x 10^8 J per meter^2 per sec