M dwarfs binaries optical spectra & light curves

Components in each pair have (1) astrometry confirming they are common-proper-motion binaries, (2) Gaia BP, RP, and 2MASS J, H, and Ks magnitudes matching within 0.10mag, and (3) presumably the same age and composition. We report long-term photometry, rotation periods, multiepoch H{alpha} equivalent widths, X-ray luminosities, time series radial velocities, and speckle observations for all components.

Although it might be expected for the twin components to have matching magnetic attributes, this is not the case. Decade-long photometry of GJ 1183 AB indicates consistently higher spot activity on A than B, a trend matched by A appearing 58%+/-9% stronger in L_X_ and 26%+/-9% stronger in H{alpha} on average-this is despite similar rotation periods of A=0.86d and B=0.68d, thereby informing the range in activity for otherwise identical and similarly rotating M dwarfs.