OGLE-2016-BLG-0263L\lowercase{b}: Microlensing Detection of a Very Low-mass Binary Companion Through a Repeating Event Channel

Abstract

We report the discovery of a planet-mass companion to the microlens OGLE-2016-BLG-0263L. Unlike most low-mass companions that were detected through perturbations to the smooth and symmetric light curves produced by the primary, the companion was discovered through the channel of a repeating event, in which the companion itself produced its own single-mass light curve after the event produced by the primary had ended. Thanks to the continuous coverage of the second peak by high-cadence surveys, the possibility of the repeating nature due to source binarity is excluded with a $96\%$ confidence level. The mass of the companion estimated by a Bayesian analysis is $M_{\mathrm{p}}=4.1_{-2.5}^{+6.5}{M}_{\mathrm{J}}$. The projected primary-companion separation is $a_{\perp }=6.5_{-1.9}^{+1.3}$ au. The ratio of the separation to the snow-line distance of $a_{\perp }/a_{\mathrm{sl}}\sim 15.4$ corresponds to the region beyond Neptune, the outermost planet of the solar system. We discuss the importance of high-cadence surveys in expanding the range of microlensing detections of low-mass companions and future space-based microlensing surveys.

10 pages, 8 figures

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Cited by in corpus (2)

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