Towards an age for every star: calibrating the age-rotation relations

Ruth Angus (University of Oxford)

September 10, 2015

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Abstract: In order to explore the evolution of planetary systems, we first need to develop a method for measuring stellar ages from photometry alone. The age-rotation, or ”gyrochronology” relations have the potential to be an extremely powerful stellar dating method, since only measurements of rotation period and mass (or mass proxy) are required to infer a star”s age. However, data from the Kepler spacecraft reveal a tension between asteroseismic and gyrochronological ages. I will discuss the potential sources of this discrepancy and ways in which we can advance our understanding of magnetic braking. New data from the Kepler and TESS spacecraft will allow us to resolve this tension and quantify the level of intrinsic scatter in the gyrochronology relations. I will demonstrate two new methods for measuring precise, accurate and probabilistic rotation periods for stars observed by Kepler and TESS. Once gyrochronology is fully understood, we will be able to infer an age for every star observed by Kepler, K2 and TESS and will, for the first time, be able to explore the impact of stellar age on planetary occurrence rates.