被归类为超级地球的系外行星通常在靠近其主恒星的短周期轨道上被观测到，但它们在更宽轨道上的丰度很少受到限制。引力微透镜对宽轨道上的系外行星很敏感。研究组观察到微透镜事件OGLE-2016-BLG-0007，这表明一颗系外行星的行星-恒星质量比大约是地-日质量比的两倍，其轨道比土星长。
研究组将这一事件与微透镜调查的更大样本结合起来，以确定宽轨道上行星的质量比分布。他们推断，在类似木星的轨道上，每颗恒星大约有0.35颗超级地球行星。观测结果与双峰分布最为一致，超级地球和气态巨行星的峰值各不相同。研究组认为这反映了其形成过程的差异。
附：英文原文
Title: Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits
Author: 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, Radosaw Poleski, Micha K. Szymański, Igor Soszyński, Pawe Pietrukowicz, Szymon Kozowski, 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
Issue&Volume: 2025-04-25
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 combined this event with a larger sample from a microlensing survey to determine the distribution of mass ratios for planets on wide orbits. We infer that 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.
DOI: adn6088
Source: https://www.science.org/doi/10.1126/science.adn6088