The PI and his team will conduct a survey of luminous dusty massive stars in nearby galaxies in order to answer many questions of stellar evolution. The stars of interest are in the late stages of massive stellar evolution and are losing mass to their environment. They include objects known as luminous blue variables (LBV), supergiant B[e], some Wolf-Rayet stars and red supergiants. The main goal of this work is to better understand how massive stars lose mass, especially episodically, is one of the outstanding open problems in stellar evolution theory. The researchers will use archived images from the Spitzer Space Telescope and new ground-based spectroscopy and imaging at optical and near-infrared wavelengths to compile color-magnitude diagrams for relevant stars in at least 20 galaxies. The measurements will be used to answer many questions, including: is a mid-infrared excess is a good marker of an LBV; is mass loss from LBV?s mostly episodic; what is the frequency of major mass ejection events; and do all massive stars undergo such outbursts?
Beyond the main science goals outlined above, the project will have broad impacts by involving a postdoctoral scholar, and graduate and undergraduate students who are already involved in the research. Also, the PI will release data to the public, and has a public outreach component that supports monthly public lectures at the Perkins Observatory. Results from this project will be of significant complementary value for astronomers once James Webb Space Telescope (JWST) is operational.
