Modelling surface brightness distribution in cool stars: SpotDIPy

The nature of magnetic field-induced activity in stars is still a subject for active research. When magnetic activity, being an important problem in stellar astrophysics studies, is not taken into account, the validity of the models can be significantly affect. In addition, its distorting effects in observational data increase the uncertainty in the calculation of planetary parameters in today's popular exoplanet studies as well as stellar parameters. There are many techniques in the literature for the investigation of magnetic activity in stars. The most effective technique that stands out among these is Doppler imaging. Although there are computer codes using the Doppler imaging technique in the literature, most of them are not shared to other researchers. In this context, in order to fill this important gap, the user-friendly and open source SpotDIPy code was developed in the Python programming language within the scope of this thesis. This code is designed to generate both surface brightness (under the two-temperature approximation) and temperature distribution maps of single stars by using the maximum entropy technique. It also has a powerful graphical user interface for visualization. In performance tests on the SpotDIPy code, it was found to be quite successful in generating maps of surface brightness and temperature distributions. In addition, Doppler imaging was performed via SpotDIPy code using the high resolution spectra of PW And and V889 Her and magnetic field-induced spot activity was investigated in these stars. The results showed that both stars have a persistently dominant high-latitude spot as well as mid-latitude spots.