Direct Imaging Discovery of a Jovian Exoplanet Within a Triple Star System

TL;DR

This paper reports the direct imaging discovery of a young Jovian exoplanet within a unique triple star system, revealing new insights into planetary formation and stability in complex stellar environments.

Contribution

It presents the first direct imaging detection of a Jovian exoplanet in a triple star system and characterizes its atmospheric properties, highlighting its unusual orbital configuration.

Findings

The exoplanet is one of the lowest mass and coldest directly imaged planets.

Its orbit is closer to the stars than any known similar exoplanet.

The planet's wide orbit suggests massive planets can exist on long, possibly unstable, orbits in multi-star systems.

Abstract

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.