We analyze the gravitational binary-lensing event OGLE-2016-BLG-0156, for which the lensing light curve displays pronounced deviations induced by microlens-parallax effects. The light curve exhibits three distinctive widely separated peaks and we find that the multiple-peak feature provides a very tight constraint on the microlensparallax effect, enabling us to precisely measure the microlens parallax π E . All the peaks are densely and continuously covered from high-cadence survey observations using globally located telescopes and the analysis of the peaks leads to the precise measurement of the angular Einstein radius θ E . From the combination of the measured π E and θ E , we determine the physical parameters of the lens. It is found that the lens is a binary composed of two M dwarfs with masses M 1 = 0.18 ± 0.01Me and M 2 =0.16 ± 0.01M ⊙ located at a distance D L = 1.35 0.09 kpc. According to the estimated lens mass and distance, the flux from the lens comprises an important fraction, ∼25%, of the blended flux. The bright nature of the lens combined with the high relative lens-source motion, ϵ= 6.94 ± 0.50 mas yr ?1 , suggests that the lens can be directly observed from future highresolution follow-up observations.
Bibliographical noteFunding Information:
Work by C.H. was supported by the grant (2017R1A4A1015178) of National Research Foundation of Korea. Work by A.G. was supported by US NSF grant AST-1516842. Work by I.G.S. and A.G. was supported by JPL grant 1500811. A.G. received support from the European Research Council under the European Union’s Seventh Framework Programme (FP 7) ERC Grant Agreement No.. The MOA project is supported by JSPS KAKENHI grant Nos. JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287. Y.M. acknowledges the support by grant JP14002006. D.P.B., A.B., and C.R. were supported by NASA through grant NASA-80NSSC18K0274. The work by C.R. was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by USRA through a contract with NASA. N.J.R. is a Royal Society of New Zealand Rutherford Discovery Fellow. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI) and the data were obtained at three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. We acknowledge the high-speed internet service (KREONET) provided by the Korea Institute of Science and Technology Information (KISTI).
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science