- #1

Haorong Wu

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- TL;DR Summary
- Is the approximation that the starlight in a long distance forms a light beam usable?

Hi. I am studying the wavefront evolution of light from a star. In the papers I have read, the star is often treated as a point source and the light is approximated as a line (geodesics), but this approximation is not very useful when I study the wavefront evolution, so I want to extend the approximation to a light beam. Here are my reasons:

I am considering a plane that is perpendicular to some direction ##\hat n_k## and is far away from the star. Then I think only photons propagating along that direction ##\hat n_k## can reach the area I am interested in, so the light can be approximated as a beam that has the same radius as the star has.

Is this approximation correct? Thanks.

I am considering a plane that is perpendicular to some direction ##\hat n_k## and is far away from the star. Then I think only photons propagating along that direction ##\hat n_k## can reach the area I am interested in, so the light can be approximated as a beam that has the same radius as the star has.

Is this approximation correct? Thanks.