Color-magnitude diagram of the three events. The CMDs (black dots) of KMT-2022-BLG-0954 and MOA-2024-BLG-018 are constructed from the OGLE-III star catalog (Szymański et al. 2011) within a 2.5′ radius centered on the event position, while the CMD of KMT-2024-BLG-0697 is built from KMTC field stars within a 2′ × 2’′ square centered on the event position. The red asterisk marks the centroid of the red clump (RC), and the blue dot indicates the source position for the best-fit 2L1S solution. The green points represent the HST CMD from Holtzman et al. (1998), whose red clump centroid, (𝑉 − 𝐼, 𝐼)RC,𝐻𝑆𝑇 = (1.62, 15.15) (Bennett et al. 2008), has been matched to that of KMTC or OGLE-III. For KMT-2022-BLG-0954, the gold and magenta dots represent the primary and secondary sources of the 1L2S model, respectively. The blue line indicates the blue boundary of the bulge main-sequence stars, derived from stellar isochrones with [M/H] = −1.0 and age > 9 Gyr. — astro-ph.EP
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 −3.7−2.0. 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.
Jiyuan Zhang, Weicheng Zang, Yoon-Hyun Ryu, Takahiro Sumi, Andrzej Udalski, Shude Mao, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Hongjing Yang, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Yunyi Tang, Leandro de Almeida, Dan Maoz, Qiyue Qian, Wei Zhu, Fumio Abe, Ken Bando, David P. Bennett, Aparna Bhattacharya, Ian A. Bond, Akihiko Fukui, Ryusei Hamada, Shunya Hamada, Naoto Hamasaki, Yuki Hirao, Stela Ishitani Silva, Naoki Koshimoto, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Tutumi Nagai, Kansuke Nunota, Greg Olmschenk, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Daisuke Suzuki, Sean K. Terry, Paul J. Tristram, Aikaterini Vandorou, Hibiki Yama, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radoslaw Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof A. Rybicki, Patryk Iwanek, Krzysztof Ulaczyk, Marcin Wrona, Mariusz Gromadzki, Mateusz J. Mróz
Comments: submitted to MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2509.18345 [astro-ph.EP] (or arXiv:2509.18345v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2509.18345
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From: Jiyuan Zhang Mr
[v1] Mon, 22 Sep 2025 19:10:51 UTC (3,057 KB)
https://arxiv.org/abs/2509.18345
AStrobiology, exoplanet,