This work here is motivated by the need for accurate physical properties of massive stars of varying metallicity in order to understand their evolution, star formation processes, and feedback mechanisms into the interstellar medium. Of particular interest is temperature, which plays a key role in transforming observations (spectral type and photometry) into physical properties (effective temperature, surface gravity, bolometric luminosity, radius, and inferred mass). In this project, an improvement of the effective temperature scales for both hot (30,000 to 50,000K) main-sequence and cool (3,000 to 4000K) evolved (red supergiant) massive stars will be undertaken This will be accomplished using high quality optical spectra (plus infrared photometry in the case of the cool giants) and the latest generation of stellar atmosphere models at both temperature extremes. Of particular importance is that these calibrations will be developed as a function of metallicity and therefore applicable to other studies of high mass stars throughout the local group. Undergraduate students will be involved in this work through the NSF sponsored Research Experiences for Undergraduates and MIT Field Camp programs. The students will be full collaborators and take part in data acquisition, analysis, writing, and the presentation of results at scientific meetings. This research will also be featured in public talks given through the Lowell Observatory visitor program and at other venues. The data collected here will also be made public once accepted for publication.
