A wide-orbit giant planet in the high-mass b Centauri binary system

Planet formation occurs around a wide range of stellar masses and stellar systemarchitectures . An improved understanding of the formation process can beachieved by studying it across the full extent of parameter space, particularlytoward the extremes. Earlier studies of planets in close-in orbits around high-massstars have revealed an increase in giant planet frequency with increasing stellarmass until a turnover point at 1.9 solar masses, above which the frequency rapidly decreases . This could potentially imply that planet formation is impeded aroundmore massive stars, and that giant planets around stars exceeding 3 solar massesmay be rare or non-existent. However, the indirect methods used to detect planetsin small orbits are insensitive to planets in wide orbits, causing ambiguity in theinterpretation of planetary frequencies. Here we demonstrate the existence of aplanet at 556 times the Sun-Earth distance from the 6—10 solar mass binary b26 Centauri through direct imaging. The planet-to-star mass ratio of 0.0010—0.0017 is similar to the Jupiter-Sun ratio, but the orbital separation of the detected planet is approximately 100 times wider than that of Jupiter. Our results show that planetscan reside in much more massive stellar systems than what would be expected fromextrapolation of previous results for close-in planets. The planet is unlikely to haveformed in-situ through the conventional core accretion mechanism4, but might haveformed elsewhere and arrived to its present location through dynamicalinteractions, or might have formed via gravitational instability.