OGLE-2018-BLG-1428Lb: a Jupiter-mass planet beyond the snow line of a dwarf star

Abstract

We present the analysis of the microlensing event OGLE-2018-BLG-1428, which has a short-duration (∼1 d) caustic-crossing anomaly. The event was caused by a planetary lens system with planet/host mass ratio q = 1.7 × 10⁻³. Because of the detection of the caustic-crossing anomaly, the finite source effect was well measured, but the microlens parallax was not constrained due to the relatively short time-scale (t_E = 24 d). From a Bayesian analysis, we find that the host star is a dwarf star M_(host) = 0.43−0.22+0.33 M⊙ at a distance D_L = 6.22−1.51+1.03 kpc and the planet is a Jovian-mass planet M_p = 0.77−0.53+0.77 M_J with a projected separation a⊥ = 3.30−0.83+0.59 au⁠. The planet orbits beyond the snow line of the host star. Considering the relative lens-source proper motion of μ_(rel) = 5.58±0.38 mas yr⁻¹⁠, the lens can be resolved by adaptive optics with a 30 m telescope in the future.

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