Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits
Abstract
Exoplanets classified as super-Earths are commonly observed on short period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to exoplanets on wide orbits. We observed the microlensing event OGLE-2016-BLG-0007, which indicates an exoplanet with a planet-to-star mass ratio roughly double the Earth-Sun mass-ratio, on an orbit longer than Saturn's. We combine this event with a larger sample from a microlensing survey to determine the distribution of mass ratios for planets on wide orbits. We infer there are super-Earth planets per star on Jupiter-like orbits. The observations are most consistent with a bimodal distribution, with separate peaks for super-Earths and gas giants. We suggest that this reflects differences in their formation processes.
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@article{arxiv.2504.20158,
title = {Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits},
author = {Weicheng Zang and Youn Kil Jung and Jennifer C. Yee and Kyu-Ha Hwang and Hongjing Yang and Andrzej Udalski and Takahiro Sumi and Andrew Gould and Shude Mao and Michael D. Albrow and Sun-Ju Chung and Cheongho Han and Yoon-Hyun Ryu and In-Gu Shin and Yossi Shvartzvald 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 Xiangyu Zhang and Renkun Kuang and Hanyue Wang and Jiyuan Zhang and Zhecheng Hu and Wei Zhu and Przemek Mróz and Jan Skowron and Radosław Poleski 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 Fumio Abe and Richard Barry and David P. Bennett and Aparna Bhattacharya and Ian A. Bond and Hirosane Fujii and Akihiko Fukui and Ryusei Hamada and Yuki Hirao and Stela Ishitani Silva and Yoshitaka Itow and Rintaro Kirikawa and Naoki Koshimoto and Yutaka Matsubara and Shota Miyazaki and Yasushi Muraki and Greg Olmschenk and Clément Ranc and Nicholas J. Rattenbury and Yuki Satoh and Daisuke Suzuki and Mio Tomoyoshi and Paul J. Tristram and Aikaterini Vandorou and Hibiki Yama and Kansuke Yamashita},
journal= {arXiv preprint arXiv:2504.20158},
year = {2025}
}
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Published in Science