OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or Super-Jupiter in a >100 au Orbit
Abstract
To search for very wide-orbit binary-lens events, we crossmatch microlensing events detected by the Optical Gravitational Lensing Experiment (OGLE)-IV and KMTNet between 2011 and 2024. After removing contaminants from variable stars, we identify OGLE-2016-BLG-0523 as a microlensing event showing two short-lived bumps in its light curve, with the two separated by 8.36 yr. We investigate three scenarios to explain the two bumps, including a binary-lens single-source (2L1S), a single-lens binary-source (1L2S), and two unrelated single-lens single-source events (2×1L1S). The 1L2S interpretation is excluded due to its poorer fit to the data, while the 2×1L1S scenario is disfavored by the low event rate, unphysical total source flux, and unphysical color for one of the two putative sources. For the surviving 2L1S interpretation, the Einstein timescales of the two bumps are 8.343 ± 0.076 days and 3.231 ± 0.047 days, respectively, implying a binary mass ratio of q = 0.15. A Bayesian analysis indicates that the primary lens is most likely a low-mass M dwarf, while the companion is probably a low-mass brown dwarf or super-Jupiter. The inferred projected separation is about 450 au, making the companion the widest low-mass object discovered via microlensing to date. Our discovery highlights both the promise and challenges of identifying very wide, low-mass companions through microlensing. Although upcoming facilities such as Roman and Earth 2.0 space telescopes will improve sensitivity to such events, overcoming degeneracies and distinguishing them from variable phenomena will remain essential for building a robust statistical sample.
Versions
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BibTeX
@article{yang2026ogle2016blg0523,
title = {{OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or Super-Jupiter in a >100 au Orbit}},
author = {Hongjing Yang and 弘靖 杨 and Weicheng Zang and 伟呈 臧 and Yoon-Hyun Ryu and Andrzej Udalski and Yuchen Tang and 雨辰 唐 and Michael D. Albrow and Sun-Ju Chung and Andrew Gould and Cheongho Han and Kyu-Ha Hwang and Youn Kil Jung and In-Gu Shin and Yossi Shvartzvald and Jennifer C. Yee and Sang-Mok Cha and Dong-Jin Kim and Hyoun-Woo Kim and Seung-Lee Kim and Chung-Uk Lee and Dong-Joo Lee and Yongseok Lee and Byeong-Gon Park and Richard W. Pogge and (The KMTNet Collaboration) and Przemek Mróz and Michał K. Szymański and Jan Skowron and Radoslaw Poleski and Igor Soszyński and Paweł Pietrukowicz and Szymon Kozłowski and Krzysztof A. Rybicki and Patryk Iwanek and Krzysztof Ulaczyk and Marcin Wrona and Mariusz Gromadzki and Mateusz J. Mróz and (The OGLE Collaboration) and Jiyuan Zhang and 纪元 张 and Shude Mao and 淑德 毛 and Hongyu Li and 弘禹 李 and Qiyue Qian and 奇玥 钱},
journal = {The Astrophysical Journal Letters},
year = {2026},
month = oct,
doi = {10.3847/2041-8213/aeb37b},
url = {https://iopscience.iop.org/article/10.3847/2041-8213/aeb37b},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or Super-Jupiter in a >100 au Orbit
AU - Hongjing Yang
AU - 弘靖 杨
AU - Weicheng Zang
AU - 伟呈 臧
AU - Yoon-Hyun Ryu
AU - Andrzej Udalski
AU - Yuchen Tang
AU - 雨辰 唐
AU - Michael D. Albrow
AU - Sun-Ju Chung
AU - Andrew Gould
AU - Cheongho Han
AU - Kyu-Ha Hwang
AU - Youn Kil Jung
AU - In-Gu Shin
AU - Yossi Shvartzvald
AU - Jennifer C. Yee
AU - Sang-Mok Cha
AU - Dong-Jin Kim
AU - Hyoun-Woo Kim
AU - Seung-Lee Kim
AU - Chung-Uk Lee
AU - Dong-Joo Lee
AU - Yongseok Lee
AU - Byeong-Gon Park
AU - Richard W. Pogge
AU - (The KMTNet Collaboration)
AU - Przemek Mróz
AU - Michał K. Szymański
AU - Jan Skowron
AU - Radoslaw Poleski
AU - Igor Soszyński
AU - Paweł Pietrukowicz
AU - Szymon Kozłowski
AU - Krzysztof A. Rybicki
AU - Patryk Iwanek
AU - Krzysztof Ulaczyk
AU - Marcin Wrona
AU - Mariusz Gromadzki
AU - Mateusz J. Mróz
AU - (The OGLE Collaboration)
AU - Jiyuan Zhang
AU - 纪元 张
AU - Shude Mao
AU - 淑德 毛
AU - Hongyu Li
AU - 弘禹 李
AU - Qiyue Qian
AU - 奇玥 钱
PY - 2026
DA - 2026/10/27
JO - The Astrophysical Journal Letters
DO - 10.3847/2041-8213/aeb37b
UR - https://iopscience.iop.org/article/10.3847/2041-8213/aeb37b
AB - To search for very wide-orbit binary-lens events, we crossmatch microlensing events detected by the Optical Gravitational Lensing Experiment (OGLE)-IV and KMTNet between 2011 and 2024. After removing contaminants from variable stars, we identify OGLE-2016-BLG-0523 as a microlensing event showing two short-lived bumps in its light curve, with the two separated by 8.36 yr. We investigate three scenarios to explain the two bumps, including a binary-lens single-source (2L1S), a single-lens binary-source (1L2S), and two unrelated single-lens single-source events (2×1L1S). The 1L2S interpretation is excluded due to its poorer fit to the data, while the 2×1L1S scenario is disfavored by the low event rate, unphysical total source flux, and unphysical color for one of the two putative sources. For the surviving 2L1S interpretation, the Einstein timescales of the two bumps are 8.343 ± 0.076 days and 3.231 ± 0.047 days, respectively, implying a binary mass ratio of q = 0.15. A Bayesian analysis indicates that the primary lens is most likely a low-mass M dwarf, while the companion is probably a low-mass brown dwarf or super-Jupiter. The inferred projected separation is about 450 au, making the companion the widest low-mass object discovered via microlensing to date. Our discovery highlights both the promise and challenges of identifying very wide, low-mass companions through microlensing. Although upcoming facilities such as Roman and Earth 2.0 space telescopes will improve sensitivity to such events, overcoming degeneracies and distinguishing them from variable phenomena will remain essential for building a robust statistical sample.
SN - 2041-8213
SN - 2041-8205
ER -