# Optical extinction

1. Jan 28, 2008

### Ayame17

Help Needed! Optical extinction

1. The problem statement, all variables and given/known data

Spherical cloud (gas to dust ratio 100) with mass = 1 M(sun), diameter = 1pc. Radial density can be described by power law (see below). Determine the maximum optical extinction, ie. the function $$A_{v}(\alpha)$$.

2. Relevant equations

Power law: $$\rho(r) \propto r^{-\alpha}$$

You may use $$N(H)=6.93*10^{21} cm^{-2}*A_{v}/R_{v}$$ and $$R_{v}=3$$

3. The attempt at a solution

I've looked up column density and found extinction values calculated by flux, but simply can't see where to even begin. A nudge in the right direction would be so very helpful!

Last edited: Jan 29, 2008
2. Jan 30, 2008