- #1

Mike89

- 4

- 0

## Homework Statement

Show that the extinction A(λ) and optical depth τ(λ) are related by the linear relationship A(λ)=1.086*τ(λ)

## Homework Equations

m(λ)=M(λ) + 5Log(d)-5 + A(λ)

which I'd rearrage to

m(λ)-M(λ)-5Log(d)+5=A(λ)

Here in lies the problem, I have all the equations I can find in my notes and the slides but nothing that relates τ(λ) to anything other than:

exp(-τ) = (I/I0) (sorry wasn't sure how to subscript the 0 in I0)

and then nothing to relate intensities to magnitudes.

## The Attempt at a Solution

I thought maybe I could use 2 stars where I new the apparent and absolute magnitudes ( the sun and vega, etc) and the distance obviously and then calculate how τ(λ) and A(λ) are related and show the 1.086 multiplier in both but I can't work out how to relate A(λ) to anything involving intensity.

I hope you guys can help me out here since I'm stumped :) thanks for anything you can