A Snapshot Survey of the Hyades

Investigations of the relationship between stellar magnetic activity androtation reveal the presence of a saturation threshold where, for unknownreasons, activity no longer varies with rotation period (Prot). However, thesestudies have focused on stars in young open clusters (<500 Myr) and field stars(210 Gyr). Measuring Prot and proxies for magnetic activity in older openclusters is essential to understand the evolution of the activityrotationrelation from the ZAMS to the age of field stars. We propose a snapshot surveyto complete the Xray census of stars with measured Prot in the 650MyroldHyades. By matching the resulting Xray catalog to our catalog of 90 HyadesProt, we will analyze the behavior of coronal activity as a function of Rossby number Ro at 650 Myr. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]