Direct imaging allows for the detection and characterization of exoplanets via their thermal emission. We report the discovery via imaging of a young Jovian planet in a triple star system and characterize its atmospheric properties through near-infrared spectroscopy. The semi-major axis of the planet is closer relative to that of its hierarchical triple star system than for any known exoplanet within a stellar binary or triple, making HD 131399 dynamically unlike any other known system. The location of HD 131399Ab on a wide orbit in a triple system demonstrates that massive planets may be found on long and possibly unstable orbits in multi-star systems. HD 131399Ab is one of the lowest mass (4+/-1 MJup) and coldest (850+/-50 K) exoplanets to have been directly imaged.
@article{arxiv.1607.02525,
title = {Direct Imaging Discovery of a Jovian Exoplanet Within a Triple Star System},
author = {Kevin Wagner and Dániel Apai and Markus Kasper and Kaitlin Kratter and Melissa McClure and Massimo Robberto and Jean-Luc Beuzit},
journal= {arXiv preprint arXiv:1607.02525},
year = {2016}
}