Magnetic Inflation and Stellar Mass IV. Four Low-mass Kepler Eclipsing Binaries Consistent with Non-magnetic Stellar Evolutionary Models. (arXiv:1907.07180v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Han_E/0/1/0/all/0/1">Eunkyu Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Muirhead_P/0/1/0/all/0/1">Philip S. Muirhead</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Swift_J/0/1/0/all/0/1">Jonathan J. Swift</a>
Low-mass eclipsing binaries show systematically larger radii than model
predictions for their mass, metallicity and age. Prominent explanations for the
inflation involve enhanced magnetic fields generated by rapid rotation of the
star that inhibit convection and/or suppress flux from the star via starspots.
However, derived masses and radii for individual eclipsing binary systems often
disagree in the literature. In this paper, we continue to investigate low-mass
eclipsing binaries (EBs) observed by NASA’s {it Kepler} spacecraft, deriving
stellar masses and radii using high-quality space-based light curves and radial
velocities from high-resolution infrared spectroscopy. We report masses and
radii for three {it Kepler} EBs, two of which agree with previously published
masses and radii (KIC 11922782 and KIC 9821078). For the third EB (KIC
7605600), we report new masses and show the secondary component is likely fully
convective ($M_2 = 0.17 pm 0.01 M_{sun}$ and $R_2 = 0.199^{+0.001}_{-0.002}
R_{sun}$). Combined with KIC 10935310 from Han et al. (2017), we find that the
masses and radii for four low-mass {it Kepler} EBs are consistent with modern
stellar evolutionary models for M dwarf stars and do not require inhibited
convection by magnetic fields to account for the stellar radii.
Low-mass eclipsing binaries show systematically larger radii than model
predictions for their mass, metallicity and age. Prominent explanations for the
inflation involve enhanced magnetic fields generated by rapid rotation of the
star that inhibit convection and/or suppress flux from the star via starspots.
However, derived masses and radii for individual eclipsing binary systems often
disagree in the literature. In this paper, we continue to investigate low-mass
eclipsing binaries (EBs) observed by NASA’s {it Kepler} spacecraft, deriving
stellar masses and radii using high-quality space-based light curves and radial
velocities from high-resolution infrared spectroscopy. We report masses and
radii for three {it Kepler} EBs, two of which agree with previously published
masses and radii (KIC 11922782 and KIC 9821078). For the third EB (KIC
7605600), we report new masses and show the secondary component is likely fully
convective ($M_2 = 0.17 pm 0.01 M_{sun}$ and $R_2 = 0.199^{+0.001}_{-0.002}
R_{sun}$). Combined with KIC 10935310 from Han et al. (2017), we find that the
masses and radii for four low-mass {it Kepler} EBs are consistent with modern
stellar evolutionary models for M dwarf stars and do not require inhibited
convection by magnetic fields to account for the stellar radii.
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