# Grain size and cross section!

1. May 9, 2013

### AriAstronomer

Hey everyone,
So I've been killing myself trying to find a good reference that talks about the wavelength dependence of dust grains when the size of the grain is about the size of the incoming light, or s~lambda. I have numerous references for when s<<lambda (absorption dominates with a s/lambda*thomson cross section dependence) and when s>>lambda (absorption again dominates and the cross section is simply the thomson cross section), but all the texts I've sifted through so far shy away from s~lambda though. My intuition tells me that in this regime where s~lambda, scattering dominates with a rayleigh scattering dependence of thomson*(s/lambda)^4, but I need a reference somewhere which talks about this. Anyone know of any??

Ari

2. May 10, 2013

### 256bits

Are you talking about Mie theory or Mie scattering as a solution to your problem.
Don't ask me how it works because I have no clue.