SOPHIE velocimetry of Kepler transit candidates ? , ? ? XIII . KOI-189 b and KOI-686 b : two very low-mass stars in long-period orbits

Content Provider	Semantic Scholar
Author	Montagnier, Guillaume Leconte, Jeremy Deleuil, Magali Bouchy, François Bruno, Giovanni Luigi Damiani, Chiara Hébrard, Guillaume Moutou, Claire
Copyright Year	2014
Abstract	We present the radial-velocity follow-up of two Kepler planetary transiting candidates (KOI-189 and KOI-686) carried out with the SOPHIE spectrograph at the Observatoire de Haute Provence. These data promptly discard these objects as viable planet candidates and show that the transiting objects are in the regime of very low-mass stars, where a strong discrepancy between observations and models persists for the mass and radius parameters. By combining the SOPHIE spectra with the Kepler light curve and photometric measurements found in the literature, we obtain a full characterization of the transiting companions, their orbits, and their host stars. The two companions are in significantly eccentric orbits with relatively long periods (30 days and 52.5 days), which makes them suitable objects for a comparison with theoretical models, since the effects invoked to understand the discrepancy with observations are weaker for these orbital distances. KOI-189 b has a mass M = 0.0745 ± 0.0033 M and a radius R = 0.1025 ± 0.0024 R . The density of KOI-189 b is significantly lower than expected from theoretical models for a system of its age. We explore possible explanations for this difference. KOI-189 b is the smallest hydrogen-burning star with such a precise determination of its fundamental parameters. KOI-686 b is larger and more massive (M = 0.0915 ± 0.0043 M ; R = 0.1201 ± 0.0033 R ), and its position in the mass-radius diagram agrees well with theoretical expectations.
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Alternate Webpage(s)	https://www.aanda.org/articles/aa/pdf/2014/12/aa24406-14.pdf
Language	English
Access Restriction	Open
Subject Keyword	Bone structure of radius Diagram Discrepancy function Distance GUCY2C protein, human Hydrogen Kepler (microarchitecture) Large Molecular orbital Ocular orbit Photometry Physical object Planetary scanner Radial (radio) Stars, Celestial Velocity (software development) XIII explanation
Content Type	Text
Resource Type	Article