A Review of Automated Stellar Spectral Classification and Surveys

Modern spectroscopic surveys and automated classifiers are becoming so inextricably linked that it is difficult even to summarize one without discussing the other. Some of the automated classifiers are being built because of current analysis needs, though with a clear anticipation of future, larger surveys. Other automated classifiers are being designed specifically for future surveys. Automated classifiers may be applied to databases already in hand, to real-time analysis at the telescope, or one day to on-board satellite analysis where the raw data are too bulky to save and transmit. In addition, many current spectroscopic surveys target galaxies. These surveys may contain stars either by accident or by a purposeful, but minority, assignment of input slits or fibers to stars. Nonetheless, these surveys still represent vast sources of stellar spectral data. Our review embarks by discussing current work, both on automated stellar classification and surveys, and then finishes with plans and portents for the future.