The Correlation Between Star Cluster Brightness and Age via B-V Photometric Analysis Kayla M. Young

Discussion After several absolute magnitudes were determined for each cluster (NGC 6633, NGC 6694 and NGC 104), it was notable that the magnitudes of cluster NGC 6694 were very strong compared to those in cluster NGC 104 which were very weak. The age of cluster NGC 6694 was the youngest at about 85 million years and the age of cluster NGC 104 was the eldest at about 10 billion years old. This study did have a few limitations, one being more star clusters could have been analyzed to receive more data. Other limitations included the program ImageJ not allowing more than 40 stars to be measured.

Conclusion The data supported the initial null hypothesis the age of the star clusters are directly correlated with the absolute magnitude. This was show in the data because the youngest cluster NGC 6694 had the strongest absolute magnitude and the oldest star cluster NGC 104 had the weakest absolute magnitude.

Future Studies Add more star clusters to compare more ages and absolute magnitudes. Using a CCD Imager and B and V filters take images of star clusters instead of using archival data. Learn how to use MaximDL for better photometric analysis.

Need The study of these celestial objects is important because they can provide information on the structure of the galaxy, provide clues to stellar evolution, and aid in calibrating knowledge of star brightnesses as well as distance. (Moffat 1972)

Purpose The purpose of this study was to find a correlation between absolute magnitude and age of star clusters.

Project Goals The goal to this project is to find a correlation between age and brightness in star clusters. Some the results are expected for the youngest cluster to have the strongest absolute magnitude and the oldest cluster to have the weakest absolute magnitude.

Literature Review An star cluster is a group of stars that are held together by gravity and whose stars lay at essentially the same distance from the earth. They are all thought to have formed at the same time, from the same materials, and under indentical conditions (Chassion 2005)

Knowledge Base All of the stars in a star cluster have similar ages, are made from similar compositions and are basically the same distance from earth. Using B-V Photometric data, age, distance and absolute magnitude can all be determined.

Bibliography NOAO (RBSE); “Star Cluster Research Project”; Vogt N., Moffat A.F.J. “Southern Open Star Clusters I.” 1972, Astronomy Astrophysics Supplement Series, Supplement 7, (1972): NASA Astrophysics Data System. Chaisson, Eric and Steve McMillan. Astronomy Today, 5th ed. New Jersey: Prentice Hall, Inc Caitlin S. Colley; “NGC 2367: It’s Age and Distance” RBSE Journal 2008 Volume 2 ; pp 43-50; 2005 University of Washington; “Cluster Color-Magnitude Diagrams and the Age of Stars”; mag.html; Feb 6, 2002 WebDA; “NGC 6633” bin/ocl_page.cgi?dirname=ngc6633 WebDA; “NGC 6694” bin/ocl_page.cgi?dirname=ngc6694