Aaron Sigut
Full Professor
Aaron Sigut
Full Professor
"I am a stellar astronomer primarily interested in massive stars. I obtained my BSc from Western in 1988 and my PhD from the University of Toronto in 1995. I was then an NSERC post-doctoral scholar at the High Altitude Observatory in Boulder, Colorado, before returning to Western in 1999 as a faculty member in the Department of Physics and Astronomy. My research mainly involves high-performance computation.
Massive stars, often called ""OB stars,"" are several times more massive than our sun and explode as supernova at the end of their lives. My research focuses on computational modelling of the spectra of massive stars. In a spectrum, the light from the star is spread out into its component colours by passage through a spectrograph, and the resultant spectrum contains important clues to the physical conditions (temperature, pressure), composition, and motion (through the Doppler effect) of the emitting gas.
One particular class of massive stars that I study extensively are the ""Be"" or B-emisison line stars. These massive stars rotate extremely rapidly, with rotation periods of just a day or two (as compared to about a month for the sun). This rapid rotation ejects material into a thin disk around the star's equator. My computational work focuses on predicting the spectra of these systems in order to determine why rapid rotation leads to the ejection of the disk, currently an unsolved problem.
Recently I have also been using the spectra of Be stars to determine the orientation of their rotation (or spin) axes in space. Massive stars, such as the Be stars, form in clusters via a complex interplay of gravity, turbulence, radiation, rotation, and magnetic fields. My work can be used to detect the alignment of stellar spins in a cluster of stars containing Be stars, and the level of alignment can provide clues to the formation process of massive stars in clusters.
I currently have two PhD students working under my supervision, one working in the area of machine learning as applied to the spectra of massive stars and one working on Ae stars, cooler analogues to the Be stars discussed above. "