Microlensing Events Indicate That Super-Earth Exoplanets Are Common In Jupiter-like Orbits

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 ∼0.35 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.

Weicheng Zang, Youn Kil Jung, Jennifer C. Yee, Kyu-Ha Hwang, Hongjing Yang, Andrzej Udalski, Takahiro Sumi, Andrew Gould, Shude Mao, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Xiangyu Zhang, Renkun Kuang, Hanyue Wang, Jiyuan Zhang, Zhecheng Hu, Wei Zhu, Przemek Mróz, Jan Skowron, Radosław Poleski, Michał K. Szymański, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Mariusz Gromadzki, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Ian A. Bond, Hirosane Fujii, Akihiko Fukui, Ryusei Hamada, Yuki Hirao, Stela Ishitani Silva, Yoshitaka Itow, Rintaro Kirikawa, Naoki Koshimoto, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Greg Olmschenk, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Daisuke Suzuki, Mio Tomoyoshi, Paul J. Tristram, Aikaterini Vandorou, Hibiki Yama, Kansuke Yamashita

Comments: Published in Science
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2504.20158 [astro-ph.EP] (or arXiv:2504.20158v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2504.20158
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Journal reference: 2025, Science, Vol 388, Issue 6745, pp. 400-404
Related DOI:
https://doi.org/10.1126/science.adn6088
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Submission history
From: Weicheng Zang
[v1] Mon, 28 Apr 2025 18:02:38 UTC (7,627 KB)
https://arxiv.org/abs/2504.20158

Astrobiology,