| Abstract: | The NASA TESS mission has as its primary goal the discovery of Earth-like planets around low-mass stars. Essential to the success of the mission will be the pre-selection of suitable, unevolved target stars, in particular bright GKM-type dwarfs. The smaller radii of unevolved dwarf stars enhance the likelihood of detecting the tiny transit signals of Earth-type planets. While reliable methods exist to effectively filter out bright giants on the basis of available colors and proper motions, filtering out G and K subgiants is very difficult, yet these are known to contaminate bright stellar samples by up to ~50%. We present initial results of new metrics utilizing WISE photometry together with 2MASS photometry and other catalog information that may allow effective discrimination between dwarf and subgiant stars. If successful, this would dramatically enhance the efficiency of the TESS mission, and could prove extremely valuable to other future surveys similarly plagued by subgiant contaminants. |