The stellar astrophysics course I am taking has been progressing well.. we’ve been covering lots of material and it’s been quite interesting. The semester culminates in a project to write computer code to model the atmosphere of a star. Late last night I finally finished my code after several days of almost continuous debugging. Now, with a calculated temperature profile of the atmosphere, my program calculates the mean intensity of the radiation at a range of frequencies (covering the the near infrared through part of the UV) at a variety of the depths in the atmosphere.

In order to solve the radiative transfer equations, we used the “Eddington Factor method” in conjunction with the “Feautrier method”. The Eddington Factor method relates the mean intensity of the radiation field to the a value similar to the radiation pressure. The Eddington factor method allows one to calculate the radiation field using knowledge of the temperature distribution and opacity in the atmosphere. Once you have the mean intensity, the Feautrier method allows you to take the mean intensity and turn it into a quantity resembling the intensity along specific angles. This can then in turn be used to refine the values of the Eddington factor, and recompute the radiation field until it converges on a solution which is consistent with the temperature distribution.

A check can be made on the temperature distribution by comparing the actual flux as a function of depth with the expected flux. This allows one to correct the temperature distribution. With the corrected temperature distribution, you can recompute the radiation field as above.

My writeup (including graphs) is available by contacting me. If there is interest in seeing my code, post a comment.