• Tuesday, October 30, 2018
  • 3:45 PM–4:45 PM
  • SB 110

Calvin student Alex Van Kooten will present a seminar entitled "“Distinguishing Stellar Populations Within Milky Way Globular Star Clusters” on October 30 at 3:45 pm in SB 110.

The Physics and Astronomy Department invites you to a seminar entitled “Distinguishing Stellar Populations Within Milky Way Globular Star Clusters” presented by Alex Van Kooten on Tuesday, October 30 at 3:45 pm in SB 110.  His presentation will be based on the research he conducted last summer with Professor Jason Smolinski.

Once thought to host a single stellar population, nearly all globular star clusters are now believed to harbor multiple stellar populations, distinguishable most often by multiple sequences on the red giant branch (RGB) of a color-magnitude diagram. The nature of these subgroups can provide insight into the formation history of globular clusters and how they have contributed to the growth of the Milky Way. Such distinct sequences of stars are not often visible to the eye on these diagrams, but with sufficiently precise photometry they can be distinguished statistically. We present our procedure to distinguish multiple populations using ground-based data from the Calvin-Rehoboth Observatory. To verify the procedure, we apply the procedure to the globular cluster Messier 13 and the evolved open cluster NGC 6791. The results of our procedure for these clusters match previously published results, giving us confidence in our procedure. We also present evidence that the somewhat arbitrary parameters used in our procedure do not introduce bias into our results. Finally, we apply our procedure to the poorly studied cluster M56 to look for multiple populations.

 Refreshments will be served at 3:30 in SB 157

Location details

Science Building Room 110