Twinkle Twinkle Little Star: ET Wonders How You Are

We present results of two projects examining the magnetic activity of nearby M dwarfs, a population of stars around which a plethora of planets is being revealed. As part of efforts by the REsearch Consortium On Nearby Stars (RECONS, www.recons.org) to characterize the Sun's neighbors, we explore stellar activity cycles in partially and fully convective M dwarfs using more than two decades of RECONS time series photometry at the CTIO/SMARTS 0.9m. We showcase light curves for several high-quality M dwarf stellar cycles in our data, with periods spanning roughly 5-30 years. These cycles have been analyzed utilizing a Gaussian Process-based method that maps periodic signals created simultaneously by long-term spot cycles and short-term rotation activity. Our second project examines magnetic activity and rotation rates for a sample of 36 M dwarf wide binaries that are made up of “twin” stars with nearly identical masses, ages, and compositions. Evolutionary models and conventional thinking suggest that such sets of twin stars should evolve nearly co-equally, resulting in similar levels of magnetic activity, and it is this assumption that we seek to test and constrain. We are targeting these systems with five ongoing observing campaigns, including short- and long-baseline optical photometry, speckle imaging, optical spectroscopy, and X-ray imaging via the Chandra X-ray observatory. We present preliminary results that indicate notable differences in magnetic activity between components for multiple twin pairs, thereby challenging our understanding of how such activity behaves.

This work has been supported by the National Science Foundation through grants AST-0507711, AST-0908402, AST-1109445, AST-141206, and AST-1715551, as well as the SMARTS Consortium.