HyPra: Anchoring the Rotation-Activity Relation At 600 Myr

Columbia University, New York NY

Investigators

Abstract

The ages of stars are notoriously difficult to determine, and our current inability to measure stellar ages is severely limiting our progress in many areas of astrophysics. For example, the age of a star is the age of its planets, and we must know the age in order to evaluate the likelihood that a given planet has conditions favorable to life. This work advances our understanding of observable proxies for age, namely a star's rotation and magnetic activity, so that we can eventually use these to obtain ages for stars less massive than the Sun. It will also support a hands-on teacher-training program that seeds and supports astronomy clubs at public schools around New York City. The existence of an age-rotation-activity relation (ARAR) has been known for 40 years now, generating hope that measurements of rotation or activity could be used to obtain the ages of isolated field stars. This project will improve the empirical calibration of the ARAR by using observations of stars in open clusters. These stars' well-defined ages make them valuable targets for measuring rotation periods and indicators of magnetic activity such as H-alpha and X-ray luminosities. The goal of the project is to complete a sensitive, unbiased survey of rotation and magnetic activity in the Hyades and Praesepe, two key, nearby 600-Myr-old clusters. New observations will be used to test the relationship between rotation and activity in a mass-independent manner. This will help calibrate the low-mass ARAR beyond 100 Myr.