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Title: Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

Abstract

Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star’s faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtainedmore » with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii.« less

Authors:
;  [1];  [2]; ;  [3];  [4];  [5];  [6];  [7]
  1. Department of Astronomy and Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)
  2. The Thacher School, 5025 Thacher Road Ojai, CA 93023 (United States)
  3. Institute for Astronomy, University of Hawaiì at Mānoa, Hilo, HI 96720-2700 (United States)
  4. Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States)
  5. California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  6. McDonald Observatory and The University of Texas, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)
  7. Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)
Publication Date:
OSTI Identifier:
22663238
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (Online)
Additional Journal Information:
Journal Volume: 154; Journal Issue: 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; CONVECTION; DWARF STARS; ECLIPSE; MAGNETIC FIELDS; METALLICITY; RADIAL VELOCITY; STARSPOTS; TELESCOPES; WAVELENGTHS

Citation Formats

Han, Eunkyu, Muirhead, Philip S., Swift, Jonathan J., Baranec, Christoph, Atkinson, Dani, Law, Nicholas M., Riddle, Reed, Mace, Gregory N., and DeFelippis, Daniel, E-mail: eunkyuh@bu.edu. Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA803C.
Han, Eunkyu, Muirhead, Philip S., Swift, Jonathan J., Baranec, Christoph, Atkinson, Dani, Law, Nicholas M., Riddle, Reed, Mace, Gregory N., & DeFelippis, Daniel, E-mail: eunkyuh@bu.edu. Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664. United States. doi:10.3847/1538-3881/AA803C.
Han, Eunkyu, Muirhead, Philip S., Swift, Jonathan J., Baranec, Christoph, Atkinson, Dani, Law, Nicholas M., Riddle, Reed, Mace, Gregory N., and DeFelippis, Daniel, E-mail: eunkyuh@bu.edu. Fri . "Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664". United States. doi:10.3847/1538-3881/AA803C.
@article{osti_22663238,
title = {Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664},
author = {Han, Eunkyu and Muirhead, Philip S. and Swift, Jonathan J. and Baranec, Christoph and Atkinson, Dani and Law, Nicholas M. and Riddle, Reed and Mace, Gregory N. and DeFelippis, Daniel, E-mail: eunkyuh@bu.edu},
abstractNote = {Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star’s faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtained with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii.},
doi = {10.3847/1538-3881/AA803C},
journal = {Astronomical Journal (Online)},
issn = {1538-3881},
number = 3,
volume = 154,
place = {United States},
year = {2017},
month = {9}
}