Don A. VandenBerg
B.Sc. (Lethbridge), M.Sc. (UVic), Ph.D. (A.N.U.)

Research Interests 

Stellar Astrophysics, Star Clusters: Modeling of the evolution of low- to intermediate-mass stars, calculation of isochrones and luminosity functions, interpretation of open and globular cluster observations.

Through a study of the Galactic globular clusters, it should be possible to answer such questions as "What is the age difference between the youngest and oldest clusters?" and "What are their spreads in age as a function of metallicity and Galactocentric distance?" Because these numbers set the basic timescales for the formation of the halo, they provide fundamental input into our understanding of how galaxies evolve. Moreover, the age of the oldest cluster is an important cosmological constraint since the universe cannot be younger than its constituents. In their on-going effort to resolve these issues, VandenBerg and his group are incorporating helium and metals diffusion into their models, studying the consequences of deep-mixing in giant-branch stars, and extending the model grids to include the horizontal-branch and asymptotic giant branch phases. These calculations, which are tightly constrained by observations, will ultimately be used to synthesize the stellar populations of distant systems. D.A.V. has also been involved in a recent HST program to search for planets and he has joined a collaboration which proposes to use the Space Interferometry Mission (SIM) to measure direct trigonometric distances to the nearest globulars.