Reply To: Astrofest 2024

Forums Spectroscopy Astrofest 2024 Reply To: Astrofest 2024

Ken Whight

Sorry if my post was a little short of information. My request is directly linked to my other topic raised in this spectroscopy section i.e. Spectral Line Modelling.
When I got interested in astronomical spectroscopy I decided to start a project to see what information I could extract from the spectra I was collecting. I was expecting to find, in the literature, a ready made simple global thermodynamic equilibrium analysis but couldn’t find one and so started to develop one myself.
It was a much more difficult task than I anticipated (I am more of a solid state physicist/mathematician/numerical modeller) and my project took about 10 (often frustrating!) years to complete but in the end I was quite successful (gaining interesting insights on the way) at determining the pressure and thickness of the Sun’s photosphere and made predictions for other stars.
Trouble is my model uses thermal equilibrium photon capture cross-sections, calculated from thermal equilibrium functions (Boltzmann & Planck) and Einstein A coefficients rather than conventional “oscillator strengths” which seem to require an additional somewhat mysterious quantum mechanical calculation.
I was hoping to meet someone who was familiar with the conventional approach to discuss how the two approaches fit together.
My sources were:-
“Astronomical Spectroscopy for Amateurs” Ken M. Harrison, Springer
“Spectroscopy: The Key to the Stars” Keith Robinson, Springer
“Atomic Astrophysics and Spectroscopy” Anil K. Pradhan and Sultana N. Nahar, Cambridge University Press