Topic: Fundamental Parameters of Cool Stars and Brown Dwarfs
The routine determination of reliable ages for single stars in the field is a goal that would impact a wide variety of areas in astronomy but which has not yet been satisfactorily achieved. Solid estimations of stellar ages are typically obtained via the fitting of theoretical isochrones, but this classical method is limited to a relatively small sample of nearby stars with extremely well-measured properties. More recently, age determinations via asteroseismology have experienced major improvements, but this occurs at the cost of quite intense photometric or spectroscopic monitoring using instrumentation that is not necessarily of the facility-type at a typical observatory. Therefore, the serious study of any alternatives to these techniques is of interest to an important community of researchers. I will present an ongoing program designed to obtain age-rotation measurements of solar-type dwarfs to be used in the calibration of gyrochronology relations at ages of several Gyr. This is a region of parameter space of importance for the large-scale study of the Milky Way, and where useful independent constraints are scarce or simply non-existent. The program takes advantage of a set of wide binaries selected so that one component is an evolved star, which provides the age of the system, and the other component is a main-sequence star of FGK type, potentially well-posed to provide a constraint useful for the empirical calibration of gyrochronology relations at the corresponding ages. I will present the current status of the program, which already includes wide binary systems with measured ages between 1 to 9 Gyr, as well as the first useful constraints for new age-rotation relations covering such a range of ages.