RETRACTED: Direct imaging discovery of a Jovian exoplanet within a triple-star system

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 semimajor 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 multistar systems. HD 131399Ab is one of the lowest mass (4 ± 1 Jupiter masses) and coldest (850 ± 50 kelvin) exoplanets to have been directly imaged.

The unstable fate of the planet orbiting the A star in the HD 131399 triple stellar system

“…All data are reproduced from Wagner et al (2016). (Wagner et al 2016). The masses and spectral types of all four objects are given in Table 1.…”

“…Spectral types and masses of the components of the HD 131399 system. All data are reproduced from Wagner et al (2016). (Wagner et al 2016).…”

“…The result is the orbital parameters given in Table 2. No orbital parameters were estimated for the mutual orbit of HD 131399B and HD 131399C, although Wagner et al (2016) report that the difference in their projected separations from HD 131399A is only about 7 au.…”

“…We performed a total of 400 simulations, split into three cases (given below) based on the error ranges in Wagner et al (2016). Within each case, we fixed the mass of HD 131399Ab to be 4M Jup , and randomly sampled from a uniform distribution (1) the arguments of pericentre, longitudes of ascending node, and mean anomalies of both orbits in Table 2, and (2) the inclinations across the ranges given in those tables.…”

“…The direct imaging discovery of a 4M Jup planet in the HD 131399 triple star system (Wagner et al 2016) -where the planet orbits E-mail: d.veras@warwick.ac.uk its single parent star at a distance of about 50-100 au -provides a helpful opportunity to study long-term stability across multiple phases of stellar evolution in a dynamically complex environment. The planet host, HD 131399A, is an A star (with a mass of about 1.8 M ), which represents the progenitor stellar type of the white dwarfs most commonly observed today (Tremblay et al 2016).…”