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arXiv · 2601.11469

KMT-2025-BLG-1616Lb: First Microlensing Bound Planet From DREAMS

Hongjing Yang·Weicheng Zang·Yoon-Hyun Ryu·Takahiro Sumi·Jiyuan Zhang·Hongyu Li·Cheongho Han·Yuchen Tang·Qiyue Qian·Zhixing Li·Yuxin Shang·Xikai Shan·Shude Mao·Guillermo Damke·Alfredo Zenteno·Steve Heathcote·Konstantina Boutsia·Przemek Mróz·Xiurui Zhao·Matthew Penny·Sean Terry·Patrick Tamburo·Timothy Cunningham·Quanzhi Ye·Eric W. Peng·Rachel Street·Katarzyna Kruszyńska·Etienne Bachelet·Yiannis Tsapras·Markus Hundertmark·Michael D. Albrow·Sun-Ju Chung·Andrew Gould·Kyu-Ha Hwang·Youn Kil Jung·In-Gu Shin·Yossi Shvartzvald·Jennifer C. Yee·Dong-Jin Kim·Chung-Uk Lee·Byeong-Gon Park·David P. Bennett·Ian A. Bond·Giuseppe Cataldo·Ryusei Hamada·Yuki Hirao·Asahi Idei·Shuma Makida·Shota Miyazaki·Tutumi Nagai·Togo Nagano·Seiya Nakayama·Mayu Nishio·Kansuke Nunota·Ryo Ogawa·Ryunosuke Oishi·Yui Okumoto·Nicholas J. Rattenbury·Yuki K. Satoh·Daisuke Suzuki·Motohide Tamura·Takuto Tamaoki·Hibiki Yama
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Abstract

We present observations and analysis of the bound planetary microlensing event KMT-2025-BLG-1616. The planetary signal was captured by the Korea Microlensing Telescope Network (KMTNet) and the DECam Rogue Earths and Mars Survey (DREAMS). DREAMS's minute-cadence observations break the central/resonant degeneracy in the binary-lens models. The color of the faint source star ($I=22$) is measured from the DREAMS's $r - z$ color. The planetary system has a planet-host mass ratio of $q \sim 5 \times 10^{-4}$. A Bayesian analysis yields a host-star mass of $\sim 0.3\,M_\odot$, a planetary mass of $\sim 40\,M_{\oplus}$, a projected planet-host separation of $\sim 1.6~\mathrm{au}$, and a lens distance of $\sim 7.5~\mathrm{kpc}$. Based on the photometric precision achieved by DREAMS for this event, we simulate free-floating planet (FFP) detections and find that DREAMS is sensitive to Mars-mass FFPs in the Galactic bulge and Moon-mass FFPs in the Galactic disk.

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Hongjing Yang, Weicheng Zang, Yoon-Hyun Ryu, Takahiro Sumi, Jiyuan Zhang, Hongyu Li, Cheongho Han, Yuchen Tang, Qiyue Qian, Zhixing Li, Yuxin Shang, Xikai Shan, Shude Mao, Guillermo Damke, Alfredo Zenteno, Steve Heathcote, Konstantina Boutsia, Przemek Mróz, Xiurui Zhao, Matthew Penny, Sean Terry, Patrick Tamburo, Timothy Cunningham, Quanzhi Ye, Eric W. Peng, Rachel Street, Katarzyna Kruszyńska, Etienne Bachelet, Yiannis Tsapras, Markus Hundertmark, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Dong-Jin Kim, Chung-Uk Lee, Byeong-Gon Park, David P. Bennett, Ian A. Bond, Giuseppe Cataldo, Ryusei Hamada, Yuki Hirao, Asahi Idei, Shuma Makida, Shota Miyazaki, Tutumi Nagai, Togo Nagano, Seiya Nakayama, Mayu Nishio, Kansuke Nunota, Ryo Ogawa, Ryunosuke Oishi, Yui Okumoto, Nicholas J. Rattenbury, Yuki K. Satoh, Daisuke Suzuki, Motohide Tamura, Takuto Tamaoki, Hibiki Yama. 2026-01-16. KMT-2025-BLG-1616Lb: First Microlensing Bound Planet From DREAMS. https://doi.org/10.3847/1538-3881%2Fae36ac

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