Year: 2014
Type: article
Abstract: We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the Hα emission line. We present optical spectra for both components of 48 candidate M dwarf binaries, confirming their mid-M spectral types. Of those 48 coeval pairs, we find eight with Hα emission from both components, three with weak emission in one component and no emission in the other, and 37 with two inactive components. We find that of the 11 pairs with at least one active component, only three follow the net trend of decreasing activity strength ( L Hα / L bol ) with later spectral type. The difference in quiescent activity strength between the A and B components is larger than what would be expected based on the small differences in color (mass). For five binaries with two active components, we present 47 hr of time-resolved spectroscopy, observed on the ARC 3.5-m over 12 different nights. For four of the five pairs, the slightly redder (B) component exhibits a higher level of Hα emission during the majority of the observations and the redder objects are the only components to flare. The full range of Hα emission observed on these variable mid-M dwarfs is comparable to the scatter in Hα emission found in single-epoch surveys of mid-M dwarfs, indicating that variability could be a major factor in the spread of observed activity strengths. We also find that variability is independent of both activity strength and spectral type.
DOI: 10.1086/679329
Authors: Heather C. Gunning, Sarah J. Schmidt, James R. A. Davenport, Saurav Dhital, Suzanne L. Hawley, Andrew A. West
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Research Corporation for Science Advancement, Princeton University, Ohio State University, University of Washington, Johns Hopkins University, University of Pittsburgh, Case Western Reserve University, Drexel University, Universität Basel, University of Portsmouth, New Mexico State University, Chinese Academy of Sciences, Max-Planck-Gesellschaft, Max-Planck-Institut für Astronomie, U.S. Naval Observatory, Fermilab, Los Alamos National Laboratory
Awards: CAREER: Probing the Extremes of Star Formation: A Census of Very Low-Mass Stars and Brown Dwarfs in the Local Neighborhood, Wide Low-Mass Binaries: Coeval Laboratories for Testing the Formation and Evolution of Stars, and the Structure and Evolution of the Milky Way, TIME DOMAIN STUDIES OF THE 2MASS CALIBRATION POINT SOURCE WORKING DATABASE:\NTHE TWO MICRON ALL SKY, Using White Dwarf-M Dwarf Pairs to Probe the Magnetic Activity and Angular Momentum Evolution of Low-Mass Stars
OpenAlex ID: W1521054648