A comprehensive analysis of three microlensing planet candidates with the planet/binary degeneracy

ABSTRACT We present observations and analyses of three high-magnification microlensing events: KMT-2022-BLG-0954, KMT-2024-BLG-0697, and MOA-2024-BLG-018. All three exhibit the ‘Planet/Binary’ degeneracy, with planetary solutions corresponding to mass ratios in the range $-3.7 < \log q < -2.2$, while the binary solutions yield $\log q > -2.0$. For KMT-2022-BLG-0954, we identify a previously unrecognized degeneracy among planetary solutions, involving different mass ratios and normalized source radii. In all three cases, single-lens binary-source models are excluded. Bayesian analyses suggest that the planetary solutions correspond to gas giants orbiting M/K dwarfs beyond the snow line, while KMT-2022-BLG-0954 also admits an alternative interpretation as a super-Earth orbiting a late-type M dwarf. The binary solutions imply a diverse set of systems, including M-dwarf pairs and M-dwarf–brown-dwarf binaries. A review of known events subject to the ‘Planet/Binary’ degeneracy shows that in most cases the degeneracy cannot be resolved through follow-up high-resolution imaging, particularly in the presence of the newly identified degeneracy.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-10-31
DOI
https://doi.org/10.1093/mnras/staf1893
Primary Topic
Stellar, planetary, and galactic studies
Type
article
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article

A comprehensive analysis of three microlensing planet candidates with the planet/binary degeneracy

Sang-Mok Cha, Yongseok Lee, I. Soszyński, Stela Ishitani Silva et al.
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
article

A comprehensive analysis of three microlensing planet candidates with the planet/binary degeneracy

Sang-Mok Cha, Yongseok Lee, I. Soszyński, Stela Ishitani Silva, Michael D. Albrow, Weicheng Zang, Hongjing Yang, Yuki Satoh, Sean K. Terry, M. Gromadzki, Kyu‐Ha Hwang, Akihiko Fukui, Shude Mao, Hibiki Yama, ‪Clément Ranc, Naoto Hamasaki, Krzysztof A. Rybicki, D. P. Bennett, M. K. Szymański, J. Skowron, Byeong-Gon Park, R. Poleski, Yoon-Hyun Ryu, Wei Zhu, Yossi Shvartzvald, Seung‐Lee Kim, Chung‐Uk Lee, Naoki Koshimoto, Cheongho Han, Aikaterini Vandorou, A. Udalski, Youn Kil Jung, Qiyue Qian, Patryk Iwanek, Shota Miyazaki, Jiyuan Zhang, Leandro de Almeida, I. A. Bond, P. Pietrukowicz, P. Mróz, K. Ulaczyk, Nicholas J. Rattenbury, Ryusei Hamada, In-Gu Shin, Greg Olmschenk, Yuki Hirao, Dan Maoz, Jennifer C. Yee, Y. Matsubara, P. J. Tristram, S. Kozłowski, Richard W. Pogge, Marcin Wrona, Y. Muraki, Mateusz J. Mróz, Kansuke Nunota, Dong-Jin Kim, Dong-Joo Lee, Aparna Bhattacharya, Tutumi Nagai, Yunyi Tang, Takahiro Sumi, Daisuke Suzuki, Sun-Ju Chung, Fumio Abe, Shunya Hamada, Andrew Gould, Ken Bando
article en

Abstract

ABSTRACT We present observations and analyses of three high-magnification microlensing events: KMT-2022-BLG-0954, KMT-2024-BLG-0697, and MOA-2024-BLG-018. All three exhibit the ‘Planet/Binary’ degeneracy, with planetary solutions corresponding to mass ratios in the range $-3.7 < \log q < -2.2$, while the binary solutions yield $\log q > -2.0$. For KMT-2022-BLG-0954, we identify a previously unrecognized degeneracy among planetary solutions, involving different mass ratios and normalized source radii. In all three cases, single-lens binary-source models are excluded. Bayesian analyses suggest that the planetary solutions correspond to gas giants orbiting M/K dwarfs beyond the snow line, while KMT-2022-BLG-0954 also admits an alternative interpretation as a super-Earth orbiting a late-type M dwarf. The binary solutions imply a diverse set of systems, including M-dwarf pairs and M-dwarf–brown-dwarf binaries. A review of known events subject to the ‘Planet/Binary’ degeneracy shows that in most cases the degeneracy cannot be resolved through follow-up high-resolution imaging, particularly in the presence of the newly identified degeneracy.

Monthly Notices of the Royal Astronomical SocietyVol. 545(4)
Centre National de la Recherche Scientifique (FR), Goddard Space Flight Center (US), University of Auckland (NZ), Chungbuk National University (KR), Tel Aviv University (IL), University of Canterbury (NZ), Korea Astronomy and Space Science Institute (KR), Japan Aerospace Exploration Agency (JP), Institut d'Astrophysique de Paris (FR), Westlake University (CN), Kyung Hee University (KR), Sorbonne Université (FR), American Committee for the Weizmann Institute of Science (US), Osaka Health Science University (JP), Southern Astrophysical Research Telescope (CL), Center for Astrophysics Harvard & Smithsonian (US), Instituto de Astrofísica de Canarias (ES), Nagoya Industrial Science Research Institute (JP), Institute of Space and Astronautical Science (JP), Astronomical Observatory (RS), Laboratório Nacional de Astrofísica (BR), University of Warsaw (PL), Massey University (NZ), The Ohio State University (US), Weizmann Institute of Science (IL), Nagoya University (JP), University of Maryland, College Park (US), The University of Tokyo (JP), Villanova University (US), Korea University of Science and Technology (KR), The University of Osaka (JP), Tsinghua University (CN)
Openalex Percentile: Top 78%
Stellar, planetary, and galactic studies
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