Emissivity of dust grains

1. Mar 21, 2013

robotopia

In this 1984 paper on circumstellar dust, the author says, speaking of the emissivity/absorption of dust grains at visual and infrared wavelengths:
My question is: where did the expression $\lambda_p / 2\pi$ come from, and what is the physical justification for it? I understand that small objects whose size is comparable to the wavelength of the incident light can't be resolved by that light, but what does that have to do with blackbody radiation and emissivity?

2. Mar 22, 2013

Chronos

Read the latest Planck mission results. They have some good information on this.

3. Mar 22, 2013

robotopia

Planck Mission results seem vast...

I made my way to this page of published results, tried to find something specifically relating to my question, and failed, feeling overwhelmed by the sheer amount of their publications. I can see that the Planck Mission is obviously very concerned with dust and its properties, and I'm sure the answer is buried in there somewhere, but in the meantime, is there a specific paper, or webpage that you could send me a link for?

4. Mar 22, 2013

Chronos

I too could find nothing specifically relevant to your question. I took the liberty of doing some additional research and came up with this: Astrophysics of Dust in Cold Clouds, http://arxiv.org/abs/astro-ph/0304488. Hope that helps

5. Mar 22, 2013

robotopia

Thanks again, Chronos. The article is helpful, but will require more careful reading to find the answer I'm looking for. I feel as though there's something basic that I'm missing, but I can't quite put my finger on it.
I'll post again if I have any luck.