The 2014-15 Frontiers of Astronomy Lecture Series will conclude today (April 16) with a talk by Alison Sills, professor in the Department of Physics & Astronomy at McMaster University in Hamilton, Ontario. Sills will give a presentation titled “Stellar Mergers and Interactions: Yes, Virginia, Stars Do Collide” at 8 p.m. in Murch Auditorium at the Cleveland Museum of Natural History.
Sills studies unusual stars in unusual places. The stars that interest her have had something happen to them during their life, such as a collision with another star or an interaction with their binary companion. These events happen more often in dense stellar clusters. Sills uses a variety of computational tools to model the formation and evolution of these clusters and their stellar populations.
She will discuss strong interactions among stars in a variety of environments. Despite the vast (average) interstellar distances, stars are social creatures and tend to live in pairs, multiples, or groups. Under these circumstances, stars can, and do, modify each other’s mass, radius, composition, and overall evolution through gravitational encounters ranging from wind mass transfer in a binary system to complete stellar collisions and mergers. Sills will show how such events can change the understanding of particular stellar systems, how they can explain the properties of many unusual objects, and how interactions could change the environment these stars live in.
The emphasis for this talk will be on the modelling of these interactions, and she will demonstrate how a combination of stellar evolution, stellar dynamics, and hydrodynamics can bring some understanding to these complicated systems.
The lecture, presented by the Case Western Reserve University Department of Astronomy through the support of the Arthur S. Holden, Sr. Endowment, the Cleveland Museum of Natural History and the Cleveland Astronomical Society, is free and open to the public. There is a $6.00 parking fee. Light refreshments will be served.
Sills will also give a special astronomy colloquium, titled “Dynamical Evolution of Very Young Stellar Sub-Clusters,” on Friday, April 17, at 12:30 p.m. in Sears Building, Room 552. Recent observations of massive, young, nearby star-forming complexes are starting to probe the detailed structure of newly forming star clusters. In particular, the MYStIX collaboration (Feigelson et al. 2013) have an extensive census of stars in 20 such regions, probing down to low masses and through significant interstellar extinction. Early results suggest that most star clusters form from a number of distinct subclusters, and that those subclusters themselves have interesting stellar age and mass distributions. In this talk, Sills will discuss results from a project to dynamically model very young, embedded subclusters, using initial conditions based on the MYStIX observations of their youngest clusters.
For more information on the lecture series, visit the Department of Astronomy’s website at astronomy.case.edu/frontiers.shtml.