OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or super-Jupiter in a >100 au Orbit

@misc{yang2026ogle2016blg0523,
  title = {{OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or super-Jupiter in a $>100$ au Orbit}},
  author = {Hongjing Yang and Weicheng Zang and Yoon-Hyun Ryu and Andrzej Udalski and Yuchen Tang 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 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 Jiyuan Zhang and Shude Mao and Hongyu Li and Qiyue Qian},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.13942},
  eprint = {2610.13942},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.13942},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - OGLE-2016-BLG-0523: A Low-mass Brown Dwarf or super-Jupiter in a >100 au Orbit
AU  - Hongjing Yang
AU  - Weicheng Zang
AU  - Yoon-Hyun Ryu
AU  - Andrzej Udalski
AU  - Yuchen Tang
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  - 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  - Jiyuan Zhang
AU  - Shude Mao
AU  - Hongyu Li
AU  - Qiyue Qian
PY  - 2026
DA  - 2026/10/13
PB  - arXiv
DO  - 10.48550/arxiv.2610.13942
UR  - https://arxiv.org/abs/2610.13942
AB  - To search for very wide-orbit binary-lens events, we cross-match microlensing events detected by 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.
ER  -