OGLE-2017-BLG-1049: Another Giant Planet Microlensing Event

Abstract

We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet-host star mass ratio of q = 9:53 ± 0.39 × 10⁻³ and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θ_E = 0.52±0.11 mas. However, the microlens parallax is not measured because the time scale of the event, t_E ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We find that the lens system has a star with mass M_h = 0.55_(−0.29)^(+0.36) M⊙ hosting a giant planet with M_p = 5.53_(−2.87)^(+3.62) M_(Jup), at a distance of D_L = 5.67_(−1.52)^(+1.11) kpc. The projected star-planet separation is a ⊥ = 3.92_(−1.32)^(+1.10) au. This means that the planet is located beyond the snow line of the host. The relative lens-source proper motion is μ_(rel) ∼ 7 mas yr⁻¹, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.

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