Transit calculates the transmission or emission spectrum of a planetary atmosphere with application to extrasolar-planet transit and eclipse observations, respectively. It computes the spectra by solving the one-dimensional line-by-line radiative-transfer equation for an atmospheric model.
https://ui.adsabs.harvard.edu/abs/2022PSJ.....3...80H , https://ui.adsabs.harvard.edu/abs/2022PSJ.....3...81C , and https://ui.adsabs.harvard.edu/abs/2022PSJ.....3...82B