EBs in Ruprecht 147. IV. EPIC 219511354 LCs & RVs

This is the fourth eclipsing system analyzed in this cluster. A combined analysis of the light curve and radial velocities yields accurate masses of M_Aa_=0.912+/-0.013M_{sun}_ and M_Ab_=0.822+/-0.010M_{sun}_ for the primary (star Aa) and secondary (Ab), along with radii of R_Aa_=0.920+/-0.016R_{sun}_ and R_Ab_=0.851+/-0.016R_{sun}_, and effective temperatures of 5035+/-150 and 4690+/-130K, respectively.

Comparison with current models of stellar evolution for the known age and metallicity of the cluster reveals that both radii are larger (by 10%-14%) and both temperatures cooler (by ~6%) than theoretically predicted, as is often seen in M dwarfs. This is likely caused by the significant stellar activity in the system, manifested here by 6% peak- to-peak out-of-eclipse variability, a filled-in H{alpha} line, and its detection as an X-ray source.