English

Four Cold Giant Planets Discovered by High-Cadence Microlensing Surveys

Earth and Planetary Astrophysics 2026-07-06 v1

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 q103q \sim 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 0.07\sim 0.07--0.6 M0.6~M_\odot and companion masses of 0.2\sim 0.2--2.5 MJ2.5~M_{\rm 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 6.6\sim 6.6--7.97.9 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.

Keywords

Cite

@article{arxiv.2607.04594,
  title  = {Four Cold Giant Planets Discovered by High-Cadence Microlensing Surveys},
  author = {Cheongho Han and Chung-Uk Lee and Andrzej Udalski and Ian A. Bond and Michael D. Albrow and Sun-Ju Chung and Andrew Gould and Youn Kil Jung and Kyu-Ha Hwang and Yoon-Hyun Ryu and Yossi Shvartzvald and In-Gu Shin and Jennifer C. Yee and Weicheng Zang and Hongjing Yang and Doeon Kim and Dong-Jin Kim and Seung-Lee Kim and Dong-Joo Lee and Sang-Mok Cha and Yongseok Lee and Byeong-Gon Park and Richard W. Pogge and Przemek Mróz and Michał K. Szymański and Jan Skowron and Radosław 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 David P. Bennett and Chihiro Ueda and Ryusei Hamada and Yuki Hirao and Shuma Makida and Shota Miyazaki and Tutumi Nagai and Seiya Nakayama and Kansuke Nunota and Ryo Ogawa and Ryunosuke Oishi and Hideaki Ose and Nicholas J. Rattenbury and Yuki K. Satoh and Takahiro Sumi and Daisuke Suzuki and Motohide Tamura and Takuto Tamaoki and Hibiki Yama},
  journal= {arXiv preprint arXiv:2607.04594},
  year   = {2026}
}

Comments

14 pages, 7 figures