Abstract
Use Eq. (12.4 of ‘Tools’) which is \(\frac {n_2}{n_1} = \frac {g_2}{g_1} \, \exp (-\frac {h\nu }{kT} )\) to estimate T for a two-state system with equal statistical weight factors and level populations n 1=1.01n 2 (where the upper state is n 2). Repeat for n 1 = 1.1 n 2. For non-Local Thermodynamic Equilibrium (LTE) conditions, T is referred to as T ex.
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Wilson, T.L., Hüttemeister, S. (2018). Spectral Line Fundamentals. In: Tools of Radio Astronomy - Problems and Solutions. Astronomy and Astrophysics Library. Springer, Cham. https://doi.org/10.1007/978-3-319-90820-5_12
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DOI: https://doi.org/10.1007/978-3-319-90820-5_12
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