Only a few wide-orbit planets around old stars have been detected, which limits our statistical understanding of this planet population. Following the systematic search for planetary anomalies in microlensing events found by the Korea Microlensing Telescope Network (KMTNet), we present the discovery and analysis of three events that were initially thought to contain wide-orbit planets. The anomalous feature in the light curve of OGLE-2018-BLG-0383 is caused by a planet with mass ratio q=2.1×10−4 and a projected separation s=2.45. This makes it the lowest mass-ratio microlensing planet at such wide orbits. The other two events, KMT-2018-BLG-0998 and OGLE-2018-BLG-0271, are shown to be stellar binaries (q>0.1) with rather close (s<1) separations. We briefly discuss the properties of known wide-orbit microlensing planets and show that the survey observations are crucial in discovering and further statistically constraining such a planet population.
@article{arxiv.2112.02414,
title = {Systematic KMTNet Planetary Anomaly Search, Paper III: One Wide-Orbit Planet And Two Stellar Binaries},
author = {Hanyue Wang and Weicheng Zang and Wei Zhu and Kyu-Ha Hwang and Andrzej Udalski and Andrew Gould and Cheongho Han and Michael D. Albrow and Sun-Ju Chung and Youn Kil Jung and Doeon Kim and Yoon-Hyun Ryu and In-Gu Shin and Yossi Shvartzvald and Jennifer C. Yee and Sang-Mok Cha and Dong-Jin Kim and Hyoun-Woo Kim and Seung-Lee Kim and Chung-Uk Lee and Dong-Joo Lee and Yongseok Lee and Byeong-Gon Park and Richard W. Pogge and Radoslaw Poleski and Przemek Mróz and Jan Skowron and Michał K. Szymański and Igor Soszyński and Paweł Pietrukowicz and Szymon Kozłowski and Krzysztof Ulaczyk and Krzysztof A. Rybicki and Patryk Iwanek and Marcin Wrona and Mariusz Gromadzki and Hongjing Yang and Shude Mao and Xiangyu Zhang},
journal= {arXiv preprint arXiv:2112.02414},
year = {2021}
}