McMaster University will continue to host undergraduate academic activities remotely for the Spring/Summer/Intersession term with only a few exceptions for courses that need student access to specialized equipment.


New Faculty Position: Tenure-Track Assistant Professor in Theoretical or Experimental Physics of Quantum Matter.


New Faculty Position: Tenure-Track Position in Experimental Radiation Physics

Alison Sills
Alison Sills
ABB 353

Alison Sills 640x192

In my research, I use knowledge of stars and stellar evolution to understand unusual stars in dense places, their interactions and their effect on their environment.

A selection of questions that my group is interested in:

  • Blue Straggler Stars
    • What are the expected pulsation characteristics of collisional & mass transfer blue straggler stars? Are those in agreement with the observations?
    • What happens to the angular momentum in a stellar collision and during the subsequent evolution of the product? Is this the same or different for binary mass transfer products?
  • Globular Cluster Formation and Dynamics:
    • How can we explain the multiple populations now seen in globular clusters? Are the current explainations viable? What other ingredients are required to fully understand this problem?
    • What are the connections between local clustered star formation and the formation & evolution of globular clusters?

I answer these questions using a variety of theoretical techniques and computer codes. Depending on the situation, I use stellar evolution codes, smoothed particle hydrodynamic codes or stellar dynamics codes, running on computers which range from laptops to supercomputers.

I am an active member of collaborations with researchers from Canada, the US and Europe, including the MODEST (MOdelling DEnse STellar Systems) collaboration and the MYStIX collaboration.

Short CV

Blue Straggler Stars, Globular Cluster Formation and Dynamics

Alison Sills
Department of Physics & Astronomy
McMaster University

Dear Prospective Graduate Student,

My work is theoretical, and covers stellar evolution, stellar dynamics, and hydrodynamics. I am interested in stellar populations that occur in unusual circumstances, such as stellar collisions in globular clusters. I study both the populations themselves and the information that the populations can give us about the environment they are in. While most of my work involves computer simulations, I also have experience working with optical observational data, particularly from the Hubble Space Telescope.

I have been at McMaster since July 2001. My most recent students worked on observations of globular cluster properties in M87 (with Bill Harris); theoretical models of star cluster formation (with James Wadsley); models of very young star clusters including both the stars and the gas; and on models of globular clusters that were formed in a dwarf galaxy which was then accreted by the Milky Way. I usually take on one or two summer or senior thesis undergraduate students as well. I may have room in my group for an exceptional graduate student this year, and have a variety of projects available, including some involving special-purpose computing hardware for stellar dynamics, binary star modelling, cluster formation and early evolution, and global cluster properties.

Astronomical research is a collaborative process, and I try to treat graduate students as collaborators as much as possible. The first few years of graduate school are an important transition from being an undergraduate student (when the answers to all questions are known) to becoming an independent researcher (when asking the right questions is as important a skill as finding the answers). All my students choose projects based on a combination of their interests and mine. MSc projects are better-defined from the beginning, and tend to involve more input from me, while PhD projects are more often suggested and planned by the students themselves. I encourage students to attend conferences, both in Canada and abroad, and I expect them to publish the results of their research in international journals at all stages.

Please contact me at  asills@mcmaster.caif you think this is a research area you might be interested in or if you have any other questions.


Go Back
McMaster University - Faculty of Science | Physics & Astronomy