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arXiv · 2302.07713

Characterization of low-mass companions to $\textit{Kepler}$ objects of interest observed with APOGEE-N

Caleb I. Cañas·Chad F. Bender·Suvrath Mahadevan·Dmitry Bizyaev·Nathan De Lee·Scott W. Fleming·Fred Hearty·Steven R. Majewski·Christian Nitschelm·Donald P. Schneider·Javier Serna·Keivan G. Stassun·Guðmundur Stefánsson·Guy S. Stringfellow·John C. Wilson
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Abstract

We report the characterization of 28 low-mass ($0.02\mathrm{~M_\odot}\le\mathrm{~M_{2}}\le0.25\mathrm{~M_\odot}$) companions to $\textit{Kepler}$ objects of interest (KOIs), eight of which were previously designated confirmed planets. These objects were detected as transiting companions to Sun-like stars (G and F dwarfs) by the $\textit{Kepler}$ mission and are confirmed as single-lined spectroscopic binaries in the current work using the northern multiplexed Apache Point Observatory Galactic Evolution Experiment near-infrared spectrograph (APOGEE-N) as part of the third and fourth Sloan Digital Sky Surveys. We have observed hundreds of KOIs using APOGEE-N and collected a total of 43,175 spectra with a median of 19 visits and a median baseline of $\sim1.9$ years per target. We jointly model the $\textit{Kepler}$ photometry and APOGEE-N radial velocities to derive fundamental parameters for this subset of 28 transiting companions. The radii for most of these low-mass companions are over-inflated (by $\sim10\%$) when compared to theoretical models. Tidally locked M dwarfs on short period orbits show the largest amount of inflation, but inflation is also evident for companions that are well separated from the host star. We demonstrate that APOGEE-N data provides reliable radial velocities when compared to precise high-resolution spectrographs that enable detailed characterization of individual systems and the inference of orbital elements for faint ($H>12$) KOIs. The data from the entire APOGEE-KOI program is public and presents an opportunity to characterize an extensive subset of the binary population observed by $\textit{Kepler}$.

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Caleb I. Cañas, Chad F. Bender, Suvrath Mahadevan, Dmitry Bizyaev, Nathan De Lee, Scott W. Fleming, Fred Hearty, Steven R. Majewski, Christian Nitschelm, Donald P. Schneider, Javier Serna, Keivan G. Stassun, Guðmundur Stefánsson, Guy S. Stringfellow, John C. Wilson. 2023-02-15. Characterization of low-mass companions to $\textit{Kepler}$ objects of interest observed with APOGEE-N. https://doi.org/10.3847/1538-4365%2Facbcbe

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