CS20 Splinter session

From light curves to rotation periods, and then ages via gyrochronology

- where do we stand, and where do we go from here?

July 30, 2018

Splinter overview

Gyrochronology – the method by which ages of cool dwarf stars can be derived from their rotation periods – is now over a decade old, and has become a useful and accepted member of the family of age indicators. The technique has many demonstrated advantages, but challenges exist, and more work is needed to extend empirical age-rotation relations to cool stars of lower mass, higher age, and non-solar metallicities. Additional uncertainties include those of applicability to binary stars or exoplanet systems of certain architectures. This splinter session will focus on these challenges, the work currently being undertaken to overcome them, and clarify what help and solutions may result from future observational developments – like TESS and PLATO, but also including modern and long-term ground-based efforts.


Relevant themes/questions are:

A. What are the prospects for establishing age-rotation relations for M dwarfs?
B. Can age-rotation relations be extended to the age of the Sun and beyond?
C. Is binarity/exoplanet architecture a problem, and if so, under what circumstances?
D. Does metallicity affect the rotational evolution of a star?
E. Additional topics (Comparision with other age indicators, supporting data, etc.)



The wave of progress ushered in by Kepler and K2 is continuing, together with steady improvements in ground-based time-series gathering. TESS will likely be launched before Cool Stars 20, and PLATO will eventually follow. M dwarfs and other low mass stars are highly sought-after targets for exoplanet searches, with the consequent desire to determine their ages. Solar-type stars in M67 have been measured, and additional efforts are underway. The literature is increasingly occupied with nonsolar-metallicity stars, and questions about the applicability of gyrochronology abound. Finally, GAIA DR2 (scheduled for Apr 2018) and following data releases will provide invaluable supporting information for both cluster and field stars. Real advantage could be taken of these events/opportunities with planning and coordination, such as that possible at this Splinter.



  • Sydney A. Barnes, Leibniz Institute for Astrophysics Potsdam (AIP), Germany
  • Silva Järvinen, Leibniz Institute for Astrophysics Potsdam (AIP), Germany
  • Søren Meibom, Harvard-Smithsonian Center for Astrophysics, USA
  • José Dias do Nascimento, Universidade Federal do Rio Grande do Norte, Brazil


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