Institute of Astronomy

Friends of Hot Jupiters:Searching for Low-Mass Stellar Companions via Spectroscopic Model Comparison

SpeakerTalk DateTalk Series
Danielle Piskorz28 July 2014Across HR 2014 Posters


Surveys of the solar neighborhood indicate that approximately half of all Sun-like stars are found in binaries or higher order multiples, but the potential effects of a stellar companion on the formation and evolution of planetary systems is unclear. Although most exoplanet surveys have focused on apparently single stars, it is possible that some of the known FGK planet-hosting stars also have unresolved stellar companions. If they exist, such companions are likely low mass M stars, which are easily overlooked in seeing-limited imaging and visible-light spectroscopy. In this study we search for stellar companions to systems with known transiting hot Jupiters. A yet-unobserved stellar companion could be dynamically responsible for a hot Jupiters misaligned orbit and shot period. Using NIRSPEC at Keck Observatory, we have acquired high-resolution spectra of fifty hot Jupiter hosts near 2.3 microns. We search for the unique molecular fingerprint of a cool stellar companion blended with the light from the hotter primary and perform a model comparison to determine the likelihood of a low-mass stellar companion contributing to the observed spectrum. This method has yielded ranked list of candidate stellar companions in these systems. Our follow-up efforts to directly resolve these companions involves high contrast adaptive optics imaging. In combination with the radial velocity (see abstract by Bryan et al.) and adaptive optics (see abstract by Ngo et al.) portions of the Friends of Hot Jupiters survey, these data allow us to place strong constraints on the frequency of stellar companions in hot Jupiter systems.


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