A Census of the Most Luminous Stars. I. The Upper HR Diagram for the Large Magellanic Cloud

Spectral classification and multiwavelength photometry for the most luminous stars in the LMC has greatly increased due to several recent surveys for both the hottest and coolest members. Combining data from these spectroscopic and photometric surveys, we have created catalogs based on their spectral classifications of the different groups: the luminous O and B stars, the A-type supergiants, and the evolved yellow and red supergiants. We derive their stellar parameters based on spectroscopic characteristics, and discuss the problems with extinction in crowded fields and the role of binarity on selected stars. Based on these surveys, we present the upper HR diagram representative of the LMC massive star population greater than 20 M⊙.