Precise Dynamical Masses and Orbital Fits for β Pic b and β Pic c

Abstract We present a comprehensive orbital analysis to the exoplanets β Pictoris b and c that resolves previously reported tensions between dynamical evolutionary mass constraints on Pic b. use Markov Chain Monte Carlo orbit code orvara fit 15 years of radial velocities relative astrometry (including recent GRAVITY measurements), absolute from Hipparcos Gaia, single velocity measurement A measure model-independent masses M Jup for 8.3 ± 1.0 c. These are robust modest changes input data selection. find well-constrained eccentricity 0.119 0.008 b, an ${0.21}_{-0.09}^{+0.16}$?> c, with two planes aligned within ∼05. Both planets’ ∼1 σ predictions hot-start models exclude cold starts. validate our approach N -body synthetic integrated using REBOUND . show can account three-body effects in system down level ∼5 times smaller than uncertainties. Systematics parameters ’s approximate treatment multiplanet orbits factor uncertainties we derive here. Future observations will improve c’s (especially) eccentricity, but improved likely require additional monitoring precision future Gaia releases.