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Educational problem
How do we know how massive stars are? How can we study the lifecycle of a star, given that it will be millions or billions of years?
To answer these questions, we need to study a coherent group of stars under “controlled
conditions” – or at least as controlled as the Universe will allow. Astronomers observe groups of stars called open clusters (relatively young stars, mainly in the early phases of their lifecycles) and globular clusters (very ancient groups of stars, containing many in the end stages of their lives).
Open clusters are loose groups of 10s or 100s of stars that were born from the same initial cloud of gas (mainly hydrogen) and dust.
Cluster stars are very useful as they are all at about the same distance from us (although as a group they are typically hundreds or thousands of light years away). By observing a group of stars in a cluster, we can assume they are all the same age, made of the same material, and that they are all the same distance away from us – so any observed differences in brightness between them are really caused by their different mass (and not by the effects of distance).
By analyzing digital images of open clusters, students can investigate the lifecycle of stars and produce their own version of the theoretical Hertzsprung-Russell diagram (HRD), on which they can identify stars at different stages of their lives. The HRD is a fundamental tool of astronomy, and the production and analysis of such a plot teaches students a great deal about measurement (using techniques known in astronomy as photometry and astrometry) and the lifecycle of stars of different masses.
Textbook teaching of this subject is inherently limited and lacks the possibility of active
investigations by the students. Also, the lack of sophisticated telescopes in schools makes direct observations of open clusters a very difficult task.
This scenario aims to fill these gaps and enable students to understand the lifecycle of stars.
Download the PDF complete version by clicking on the following link: open_clusters_educational_scenario.pdf
Educational content developed by Glamorgan University (UK).
Validated by Discover the Cosmos + Open Clusters
Last update | 20/06/2013