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dc.contributor.authorCrossfield, Ian
dc.contributor.authorLothringer, J. D.
dc.contributor.authorFlores, B.
dc.contributor.authorMills, E. A. C.
dc.contributor.authorFreedman, R.
dc.contributor.authorValverde, J.
dc.contributor.authorMiles, B.
dc.contributor.authorGuo, X.
dc.contributor.authorSkemer, A.
dc.identifier.citationI. J. M. Crossfield et al 2019 ApJL 871 L3en_US
dc.descriptionThis work is licensed under a Creative Commons Attribution 4.0 International License.en_US
dc.description.abstractLow-mass M dwarfs represent the most common outcome of star formation, but their complex emergent spectra hinder detailed studies of their composition and initial formation. The measurement of isotopic ratios is a key tool that has been used to unlock the formation of our solar system, the Sun, and the nuclear processes within more massive stars. We observed GJ 745AB, two M dwarfs orbiting in a wide binary, with the NASA Infrared Telescope Facility/iSHELL spectrograph. Our spectroscopy of CO in these stars at the 4.7 μm fundamental and 2.3 μm first-overtone rovibrational bandheads reveals ${}^{12}{{\rm{C}}}^{16}{\rm{O}}$, ${}^{13}{{\rm{C}}}^{16}{\rm{O}}$, and ${}^{12}{{\rm{C}}}^{18}{\rm{O}}$ in their photospheres. Because the stars are fully convective, the atomic constituents of these isotopologues should be uniformly mixed throughout the stars' interiors. We find that in these M dwarfs, both ${}^{12}{\rm{C}}$/${}^{13}{\rm{C}}$ and ${}^{16}{\rm{O}}$/${}^{18}{\rm{O}}$ greatly exceed the Solar values. These measurements cannot be explained solely by models of Galactic chemical evolution, but require that the stars formed from an interstellar medium significantly enriched by material ejected from an exploding core-collapse supernova. These isotopic measurements complement the elemental abundances provided by large-scale spectroscopic surveys, and open a new window onto studies of Galactic evolution, stellar populations, and individual systems.en_US
dc.publisherAmerican Astronomical Societyen_US
dc.rights© 2019. The American Astronomical Society.en_US
dc.subjectInfrared: starsen_US
dc.subjectTechniques: spectroscopicen_US
dc.subjectStars: abundancesen_US
dc.subjectSupernovae: generalen_US
dc.titleUnusual Isotopic Abundances in a Fully Convective Stellar Binaryen_US
kusw.kuauthorCrossfield, Ian
kusw.kudepartmentPhysics and Astronomyen_US
kusw.oaversionScholarly/refereed, publisher versionen_US
kusw.oapolicyThis item meets KU Open Access policy criteria.en_US

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© 2019. The American Astronomical Society.
Except where otherwise noted, this item's license is described as: © 2019. The American Astronomical Society.