KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed due to source binarity
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Date
2023-10
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
EDP Sciences, France
Rights
(c) 2023 The Author/s
CC BY 4.0
CC BY 4.0
Abstract
Aims. We investigate the previous microlensing data collected by the KMTNet survey in search of anomalous events for which no precise interpretations of the anomalies had been suggested. From this investigation, we find that the anomaly in the lensing light curve of the event KMT-2021-BLG-1547 is approximately described by a binary-lens (2L1S) model with a lens possessing a giant planet, but the model leaves unexplained residuals.
Methods. We investigated the origin of the residuals by testing more sophisticated models that include either an extra lens component (3L1S model) or an extra source star (2L2S model) on top of the 2L1S configuration of the lens system. From these analyses, we find that the residuals from the 2L1S model originate from the existence of a faint companion to the source. The 2L2S solution substantially reduces the residuals and improves the model fit by δ x 2 = 67.1 with respect to the 2L1S solution. The 3L1S solution also improves the fit, but its fit is worse than that of the 2L2S solution by δ x 2 = 24.7.
Results. According to the 2L2S solution, the lens of the event is a planetary system with planet and host masses (Mp/MJ, Mh/M·) = (1.47-0.77+0.64, 0.72-0.38+0.32) lying at a distance DL = 5.07-1.50+0.98 kpc, and the source is a binary composed of a subgiant primary of a late G or an early K spectral type and a main-sequence companion of a K spectral type. The event demonstrates the need for sophisticated modeling of unexplained anomalies if one wants to construct a complete microlensing planet sample.
Description
Keywords
gravitational lensing, micro / planets and satellites, detection
Citation
Han C, Zang W, Jung YK, Bond IA, Chung SJ, Albrow MD, Gould A, Hwang KH, Ryu YH, Shin IG, Shvartzvald Y, Yang H, Yee JC, Cha SM, Kim D, Kim DJ, Kim SL, Lee CU, Lee DJ, Lee Y, Park BG, Pogge RW, Monard B, Qian Q, Liu Z, Maoz D, Penny MT, Zhu W, Abe F, Barry R, Bennett DP, Bhattacharya A, Fujii H, Fukui A, Hamada R, Hirao Y, Ishitani Silva S, Itow Y, Kirikawa R, Kondo I, Koshimoto N, Matsubara Y, Miyazaki S, Muraki Y, Olmschenk G, Ranc C, Rattenbury NJ, Satoh Y, Sumi T, Suzuki D, Tomoyoshi M, Tristram PJ, Vandorou A, Yama H, Yamashita K. (2023). KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed due to source binarity. Astronomy and Astrophysics. 678. October 2023.