Investigation of chemical evolution of the solar neighbourhood

In the thesis study, the chemical evolution of the solar neighbourhood was investigated. With the help of GALAH, APOGEE and GAIA sky surveys, a data set that considers both the southern and northern hemispheres with spectral, astrometric and chemical abundance information was created. This created data set is heliocentric and well expressed the Solar Neighbourhood. The created thesis catalogue is classified according to luminosity classes and galactic populations with the help of machine learning methods. Populations were successfully separated from each other in both chemical and kinematic planes by using the chemical abundances and space velocities of the stars. With the help of precise astrometric data from GAIA and the \textit{galpy} library, dynamic orbital parameters were calculated under the gravitational potential of the Galaxy. The gradients were calculated in the direction of the mean orbital radius ($R_m$) for five different elements (Mg, Si, Ca, Ti, Fe) from the stars seperated into their luminosity class and Galactic populations. The calculated gradients are in agreement with the literature. By dividing the solar neighbourhoodinto three different $R_{GC}$ intervals, the Delayed Two-Infall Model for each interval was applied to the $[Fe/H]\times[Mg/Fe]$ plane with the help of Markov Chain Monte Carlo simulation, and the Delayed Two-Infall Model of each region was determined. Model input parameters were obtained. With the help of the obtained input parameters, an evolution model was created for five different elements through three different radius regions. With the help of the models created, the variation of elemental abundance of three different regions over time was estimated and based on the predictions, the current observational features of the Galaxy were obtained according to the model, and these parameters were compared with the values from the data and the literature, and found to be compatible. Thanks to the model predictions obtained for three different regions, the unobservable features of the solar neighbourhood were predicted and the chemical evolution process of the solar neighbourhood was revealed in the thesis study with the help of these predictions.