Discovering the Solar Corona Luminosity Curve: Explained and Explored

[Eleftheria]

I've been trying to find out what's the curve for the solar corona luminosity vs distance like.
I know that the corona can be practically observed up to 4 solar radii. I also found out that the curve is more or less exponential but I need the actuall equation of the curve.

Can anyone help me?

 

[Astronuc]

This might help. See fig. 4 in - http://www.sp.ph.ic.ac.uk/~mkd/AndreHandout.pdf

 

[Eleftheria]

Judging by that figure I assume that the difference in temperature (from the lowest to the highest value) for the corona is about 1 500 000 K (more or less), which means that the lowest value must be multiplied by 10 to reach the highest.
So, based on the equation that relates temperature and luminosity [L=4π(R^2)σ(T^4)] I guess the difference in luminosity (from the lowest to the highest value) can be found if we multiply the lowest values by 10^4.

Am I right?