KMT-2022-BLG-0086: Another Binary-lens Binary-source Microlensing Event
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Date
2025-07-08
Open Access Location
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IOP Publishing Limited, Bristol, England, for the Institute of Physics
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(c) 2025 The Author/s
CC BY 4.0
CC BY 4.0
Abstract
We present the analysis of a microlensing event KMT-2022-BLG-0086 of which the overall light curve is not described by a binary-lens single-source (2L1S) model, which suggests the existence of an extra lens or an extra source. We found that the event is best explained by the binary-lens binary-source (2L2S) model, but the 2L2S model is only favored over the triple-lens single-source (3L1S) model by Δχ<sup>2</sup> ≃ 9. Although the event has noticeable anomalies around the peak of the light curve, they are not enough covered to constrain the angular Einstein radius θ<inf>E</inf>, thus we only measure the minimum angular Einstein radius <inf>E,min</inf>. From the Bayesian analysis, it is found that that the binary lens system is a binary star with masses of (m<inf>1</inf>, m<inf>2</inf>) = (0.46<sup>+</sup><inf>0.25 _</inf><sup>0.35</sup> M , 0.75<sup>+</sup><inf>0.55 _</inf><sup>0.67</sup> M ) at a distance of D<inf>L</inf> = 5.87<sup>+</sup><inf>1.79 _</inf><sup>1.21</sup> kpc, while the triple lens system is a brown dwarf or a massive giant planet in a low-mass binary-star system with masses of (m<inf>1</inf>, m<inf>2</inf>, m<inf>3</inf>) = (0.43<sup>+</sup><inf>0.35 _</inf><sup>0.41</sup> M , 0.056<sup>+</sup><inf>0.047 _</inf><sup>0.055</sup> M , 20.84<sup>+</sup><inf>17.04 _</inf><sup>20.20</sup> M<inf>J</inf>) at a distance of D<inf>L</inf> = 4.06<sup>+</sup><inf>3.28 _</inf><sup>1.39</sup> kpc, indicating a disk lens system. The 2L2S model yields the relative lens-source proper motion of μ<inf>rel</inf> ≥ 4.6 mas yr<sup>−1</sup> that is consistent with the Bayesian result, whereas the 3L1S model yields μ<inf>rel</inf> ≥ 18.9 mas yr<sup>−1</sup>, which is more than three times larger than that of a typical disk object of ∼6 mas yr<sup>−1</sup> and thus is not consistent with the Bayesian result. This suggests that the event is likely caused by the binary-lens binary-source model.
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Chung SJ, Hwang KH, Yee JC, Gould A, Bond IA, Yang H, Albrow MD, Jung YK, Han C, Ryu YH, Shin IG, Shvartzvald Y, Zang W, Cha SM, Kim DJ, Kim SL, Lee CU, Lee DJ, Lee Y, Park BG, Pogge RW, Abe F, Bennett DP, Bhattacharya A, Fukui A, Hamada R, Hirao Y, Silva SI, Koshimoto N, Miyazaki S, Muraki Y, Nagai T, Nunota K, Olmschenk G, Ranc C, Rattenbury NJ, Satoh Y, Sumi T, Suzuki D, Terry SK, Tristram PJ, Vandorou A, Yama H. (2025). KMT-2022-BLG-0086: Another Binary-lens Binary-source Microlensing Event. Astronomical Journal. 170. 2.