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Characterizing M Dwarf Stellar Cycles with Two Decades of RECONS Data

Published onJun 01, 2020
Characterizing M Dwarf Stellar Cycles with Two Decades of RECONS Data

We discuss initial results from our comprehensive effort to investigate the presence of long-term photometric variability for nearby M dwarfs, using more than two decades of data obtained by the REsearch Consortium On Nearby Stars (RECONS, Understanding stellar cycles in M dwarfs is critical to informing the viability of these common stars as habitable exoplanet hosts, and in determining the underlying dynamo mechanism that drives M dwarf magnetic activity. Our volume complete sample consists of 455 M dwarfs within 16.7 pc (parallax cutoff of 60 milliarcseconds) in the southern sky. These survey stars have a median baseline of approximately 10 years of coverage already, while ongoing observations at the SMARTS 0.9m at CTIO provide additional data 4-6 times per year. We are using these data — in conjunction with sources such as ASAS, MEarth, KELT, and TESS — to determine representative statistics for the underlying properties of stellar cycles in M dwarfs, and to search for correlations between stellar cycles and magnetic activity on shorter timescales such as flaring and rotation. We have identified several dozen new stellar cycles so far, and here we present light curves and period estimates for many high-quality cycles in the RECONS data. We also discuss our efforts to determine the magnetic predictability of M dwarfs by observing 36 ‘twin’ binary systems within 50 pc. GJ1183AB stands out in this search so far as a binary with components showing marked differences in magnetic activity despite being nearly the same in mass and presumed to have identical ages and compositions. This effort has been supported by the NSF through grant AST-1715551 and via observations made possible by the SMARTS Consortium.


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