Is there a 'simple' YORP calculation

[higginsdj]

I known the calculation of the YORP effect on an object is quite complex (I have a lot of papers on the subject and all the math is a little beyond me) and is based on the objects shape, distance from the sun and size, but is there a 'simple' version that will allow one to calculate a 'ballpark' based on an 'average' asteroid shape, distance from the sun and diameter of the object?

Cheers

David

 

[higginsdj]

Never mind, I found 'Rubincam's approximation' by Dr Alan Harris:

dw/dt ~ +/- 18/(a^2*D^2)

where a = semi major axis in AU and D = diameter in km and the result is the difference in cycles per day per million years.

Cheers

David