First Ever Image of a Multi-Planet System around a Sun-like Star Captured by ESO Telescope

The European Southern Observatory’s Very Large Telescope (ESO’s VLT) has taken the first ever image of a young, Sun-like star accompanied by two giant exoplanets. Images of systems with multiple exoplanets are extremely rare, and — until now — astronomers had never directly observed more than one planet orbiting a star similar to the Sun. The observations can help astronomers understand how planets formed and evolved around our own Sun.

Abstract: Even though tens of directly imaged companions have been discovered in the past decades, the number ofdirectly confirmed multi-planet systems is still small. Dynamical analysis of these systems imposes importantconstraints on formation mechanisms of these wide-orbit companions. As part of the Young Suns ExoplanetSurvey (YSES) we report the detection of a second planetary-mass companion around the 17 Myr-old, solar-type star TYC 8998-760-1 that is located in the Lower Centaurus Crux subgroup of the Scorpius-Centaurusassociation. The companion has a projected physical separation of 320 au and several individual photometricmeasurements from 1.1 to 3.8 microns constrain a companion mass of 6 ± 1 MJup, which is equivalent to a mass ratio of q= 0.57 ± 0.10 % with respect to the primary. With the previously detected 14 ± 3 MJup companionthat is orbiting the primary at 160 au, TYC 8998-760-1 is the first directly-imaged multi-planet system that isdetected around a young, solar analogue. We show that circular orbits are stable, but that mildly eccentric orbitsfor either/both components (e > 0.1) are chaotic on Gyr timescales, implying in-situ formation or a very specificejection by an unseen third companion. Due to the wide separations of the companions TYC 8998-760-1 is anexcellent system for spectroscopic and photometric follow-up with space-based observatories such asJWST.