Four Cold Giant Planets Discovered by High-Cadence Microlensing Surveys
Cheongho Han, Chung-Uk Lee, Andrzej Udalski, Ian A. Bond, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Youn Kil Jung, Kyu-Ha Hwang, Yoon-Hyun Ryu, Yossi Shvartzvald, In-Gu Shin, Jennifer C. Yee, Weicheng Zang, Hongjing Yang, Doeon Kim, Dong-Jin Kim, Seung-Lee Kim, Dong-Joo Lee, Sang-Mok Cha, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radosław Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof A. Rybicki, Patryk Iwanek, Krzysztof Ulaczyk, Marcin Wrona, Mariusz Gromadzki, Mateusz J. Mróz, David P. Bennett, Chihiro Ueda, Ryusei Hamada, Yuki Hirao, Shuma Makida, Shota Miyazaki, Tutumi Nagai, Seiya Nakayama, Kansuke Nunota, Ryo Ogawa, Ryunosuke Oishi, Hideaki Ose, Nicholas J. Rattenbury, Yuki K. Satoh, Takahiro Sumi, Daisuke Suzuki, Motohide Tamura, Takuto Tamaoki, Hibiki Yama
astro-ph.EP
Submitted: 2026-07-06
Comments: 14 pages, 7 figures
License: http://creativecommons.org/licenses/by/4.0/
The gist: We report the discovery of four cold giant planets identified through the analysis of microlensing events detected by high-cadence surveys: OGLE-2016-BLG-0261, KMT-2025-BLG-0026, KMT-2025-BLG-0030,
Terminology
Abstract
We report the discovery of four cold giant planets identified through the analysis of microlensing events detected by high-cadence surveys: OGLE-2016-BLG-0261, KMT-2025-BLG-0026, KMT-2025-BLG-0030, and KMT-2025-BLG-2272. The planetary signals appear as short-duration anomalies in the light curves and are well described by binary-lens single-source models with mass ratios between the lens components of order q about 10-3. Finite-source effects are securely measured in three out of four events, enabling determinations of the angular Einstein radius. A Bayesian analysis incorporating the measured event timescale and angular Einstein radius yields host masses of about 0.07 -- 0.6 M and companion masses of about 0.2 -- 2.5 M J, confirming that all companions lie in the giant-planet regime. The projected separations are 0.7--6 au, placing all planets at or beyond the snow lines of their host stars. The inferred lens distances span about 6.6 -- 7.9 kpc, with all systems consistent with bulge lenses. These detections expand the sample of cold giant planets from homogeneous high-cadence surveys and highlight the sensitivity of microlensing to planetary systems beyond the snow line, providing further constraints on the occurrence and properties of giant planets around low-mass stars.
Sources
- The binary gravitational lens and its extreme cases
- OGLE-IV: Fourth Phase of the Optical Gravitational Lensing Experiment
- Difference Image Analysis of the OGLE-II Bulge Data. I. The Method
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