Spectral investigations of planetary nebulae and candidates selected from the Northern Hemisphere

Planetary Nebula (PN) is a celestial object which have occurred from ionized material ejected into the ISM while low to intermediate mass stars between Asymptotic Giant Branch and White Dwarf are reaching their end of evolutions. PNe have play a key role in many aspects such as understanding and enriching the interstellar medium, stages of stellar evolution. In this thesis, spectral investigations of 15 PNe and 13 PN candidates from the northern hemisphere (Dec > -10) were made. The spectral data of the sources were obtained with the TUG Faint Object Spectrograph and Camera (TFOSC) mounted on Russian-Turkish Telescope 150 cm (RTT150) at the TUBITAK National Observatory (TUG). In total, 18 sources were observed spectroscopically for the first time. Physical parameters such as electron temperature (in between 5700 – 17000 K), electron density (in between 100 – 12000 cm-3), extinction coefficient (in between 0,70 – 4,00), elemental abun-dances and excitation classes were determined from the emission line ratios. Four of the PN candidates were confirmed to be True PN using diagnostic plots. The physical parameters that could not be determined from the emission lines measured with the help of the photoionization code were determined.