A study of southern galactic clusters and the peculiar stars associated with them

Abstract

Although the peculiar A stars have been the subject of' intensive study for many years, their spectral peculiarities have yet to be satisfactorily explained. Many examples of' these stars were noted in the Henry Draper Catalogue, and descriptions of many bright examples are to be found in the earlier works of' Maury & Pickering (1897) and Cannon & Pickering (1901). The first major attempt at classifying the spectra of' these stars was the series of' papers by Morgan (19J1a,b, 1932a,b) culminating in his descriptive study of' A star spectra (1935). He showed that the normal two dimensional spectral classification scheme was inadequate f'or the description of their spectra, and classified them into several groups according to their outstanding peculiarities. He also showed that there was an apparent correlation between the effective excitation conditions in these stars and the predominant peculiarity. The classification in most co Show more