Resolved Stellar Populations from Hubble
The unprecedented resolution of the Hubble Space Telescope enables the study of individual stars in nearby galaxies like M81, pictured at right. I'm currently working on a project to use the properties of individual stars to determine the star formation history of specific regions of M81, and how that history ties in with the compact object (neutron stars, black holes) population which is most easily seen in the X-ray. Systems with two such objects are the progenitors of gravitational wave events predicted by Einstein.
Massive Stars in Nearby Galaxies
The role of mass loss from massive stars, particularly episodic mass loss in evolved massive stars, is one of the open questions facing stellar evolution theory. My group and I are working on a census of rare, luminous, dusty massive stars selected via mid-IR color-magnitude diagrams produced from archival Spitzer Space Telescope images. We will then follow up identified sources with spectroscopy to further characterize the massive star content of nearby galaxies such as M83 (seen at left -- taken from the ESO archive).
Binary Stars
The study of binary stars allow us to determine fundamental properties of stars such as mass, radius, age and so on. I am in the process of analyzing a range of Galactic eclipsing binaries to determine these properties. My focus is on stars from a few times more massive than our Sun to tens of times more massive than our Sun, such as the system HI Mon, a model of which is shown at right. Shown at left is an artist's rendition of a massive binary in the Large Magellanic Cloud, [L72] LH 54-425.
