Potsdam Cluster Project: An improved understanding of stellar rotation and ages using open cluster benchmarks

• Applicant: Dr. Sydney A. Barnes
• Subject Area: Astrophysics and Astronomy
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 573279422

A key problem in Astrophysics is the creation of a timeline, a chronology of phases and events, for the evolution of our galaxy -- similar to the evolutionary phases earth science has established for the history of the earth. Such a timeline allows us to distinguish cause and effect in Galactic phenomena and to place individual objects such as particular stars and exoplanets in a larger context. A fundamental aspect in the creation of such a timeline is the accurate age dating of objects in our galaxy -- a non-trivial task. Cool main sequence stars are among the most common objects in the Galaxy but their ages are particularly difficult to derive because their classical properties do not change much during their long main sequence lifetimes. There is also the added interest in such stars as they host the vast majority of detected exoplanets. There is considerable evidence now that the systematic changes in rotation rates of cool stars with age can both be measured precisely enough, and also placed in appropriate sequential form for useful ages to be derivable. The associated methodology was named gyrochronology. Ages derived this way, in concert with those from adjacent fields such as asteroseismology and classical isochrone ages (each appropriately applicable to different types of stars), are becoming increasingly important with missions such as Kepler/K2, TESS, GAIA, and with the imminent PLATO mission. Our team has played a significant role in developing this field using both ground-based and space-based observations. However, it is in need of further exploration and development. We propose here to measure certain specific benchmark open clusters using both available space data and new data to be acquired with our ground-based STELLA observatory to fill certain important gaps in the available data, and to extend knowledge to older ages than is currently possible.

• DFG Programme: Research Grants