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Register a new userOGLE-2018-BLG-1011Llowercase{b,c}: Microlensing Planetary System with Two Giant Planets Orbiting a Low-mass Star
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We report a multiplanetary system found from the analysis of microlensing event OGLE-2018-BLG-1011, for which the light curve exhibits a double-bump anomaly around the peak. We find that the anomaly cannot be fully explained by the binary-lens or binary-source interpretations and its description requires the introduction of an additional lens component. The 3L1S (3 lens components and a single source) modeling yields three sets of solutions, in which one set of solutions indicates that the lens is a planetary system in a binary, while the other two sets imply that the lens is a multiplanetary system. By investigating the fits of the individual models to the detailed light curve structure, we find that the multiple-planet solution with planet-to-host mass ratios $sim 9.5times 10^{-3}$ and $sim 15times 10^{-3}$ are favored over the other solutions. From the Bayesian analysis, we find that the lens is composed of two planets with masses $1.8^{+3..4}_{-1.1}~M_{rm J}$ and $2.8^{+5.1}_{-1.7}~M_{rm J}$ around a host with a mass $0.18^{+0.33}_{-0.10}~M_odot$ and located at a distance $7.1^{+1.1}_{-1.5}~{rm kpc}$. The estimated distance indicates that the lens is the farthest system among the known multiplanetary systems. The projected planet-host separations are $a_{perp,2}=1.8^{+2.1}_{-1.5}~{rm au}$ ($0.8^{+0.9}_{-0.6}~{rm au}$) and $a_{perp,3}=0.8^{+0.9}_{-0.6}~{rm au}$, where the values of $a_{perp,2}$ in and out the parenthesis are the separations corresponding to the two degenerate solutions, indicating that both planets are located beyond the snow line of the host, as with the other four multiplanetary systems previously found by microlensing.
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We present the analyses of two microlensing events, OGLE-2018-BLG-0567 and OGLE-2018-BLG-0962. In both events, the short-lasting anomalies were densely and continuously covered by two high-cadence surveys. The light-curve modeling indicates that the anomalies are generated by source crossings over the planetary caustics induced by planetary companions to the hosts. The estimated planet/host separation (scaled to the angular Einstein radius $theta_{rm E}$) and mass ratio are $(s, q) = (1.81, 1.24times10^{-3})$ and $(s, q) = (1.25, 2.38times10^{-3})$, respectively. From Bayesian analyses, we estimate the host and planet masses as $(M_{rm h}, M_{rm p}) = (0.24_{-0.13}^{+0.16},M_{odot}, 0.32_{-0.16}^{+0.34},M_{rm J})$ and $(M_{rm h}, M_{rm p}) = (0.55_{-0.29}^{+0.32},M_{odot}, 1.37_{-0.72}^{+0.80},M_{rm J})$, respectively. These planetary systems are located at a distance of $7.07_{-1.15}^{+0.93},{rm kpc}$ for OGLE-2018-BLG-0567 and $6.47_{-1.73}^{+1.04},{rm kpc}$ for OGLE-2018-BLG-0962, suggesting that they are likely to be near the Galactic bulge. The two events prove the capability of current high-cadence surveys for finding planets through the planetary-caustic channel. We find that most published planetary-caustic planets are found in Hollywood events in which the source size strongly contributes to the anomaly cross section relative to the size of the caustic.
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We report the discovery of an extrasolar planet detected from the combined data of a microlensing event OGLE-2015-BLG-0051/KMT-2015-BLG-0048 acquired by two microlensing surveys. Despite that the short planetary signal occurred in the very early Bulge season during which the lensing event could be seen for just about an hour, the signal was continuously and densely covered. From the Bayesian analysis using models of the mass function, matter and velocity distributions combined with the information of the angular Einstein radius, it is found that the host of the planet is located in the Galactic bulge. The planet has a mass $0.72_{-0.07}^{+0.65} M_{rm J}$ and it is orbiting a low-mass M-dwarf host with a projected separation $d_perp=0.73 pm 0.08$ AU. The discovery of the planet demonstrates the capability of the current high-cadence microlensing lensing surveys in detecting and characterizing planets.
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