http://arxiv.org/abs/1911.11953
We present the analysis of the microlensing event OGLE-2016-BLG-1227. The light curve of this short-duration event appears to be a single-lens event affected by severe finite-source effects. Analysis of the light curve based on single-lens single-source (1L1S) modeling yields very small values of the event timescale, $t_{\rm E}\sim 3.5$ days, and the angular Einstein radius, $\theta_{\rm E}\sim 0.009$ mas, making the lens a candidate of a free-floating planet. Close inspection reveals that the 1L1S solution leaves small residuals with amplitude $\Delta I\lesssim 0.03$ mag. We find that the residuals are explained by the existence of an additional widely-separated heavier lens component, indicating that the lens is a wide-separation planetary system rather than a free-floating planet. From Bayesian analysis, it is estimated that the planet has a mass of $M_{\rm p} = 0.79^{+1.30}{-0.39} M{\rm J}$ and it is orbiting a low-mass host star with a mass of $M_{\rm host}=0.10^{+0.17}{-0.05} M\odot$ located with a projected separation of $a_\perp=3.4^{+2.1}{-1.0}$ au. The planetary system is located in the Galactic bulge with a line-of-sight separation from the source star of $D{\rm LS}=1.21^{+0.96}_{-0.63}$ kpc. The event shows that there are a range of deviations in the signatures of host stars for apparently isolated planetary lensing events and that it is possible to identify a host even when a deviation is subtle.
C. Han, A. Udalski, A. Gould, et. al.
Thu, 28 Nov 19
37/70
Comments: 8 figures, 4 tables
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