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arXiv · 2210.02436

MOA-2020-BLG-208Lb: Cool Sub-Saturn Planet Within Predicted Desert

Abstract

We analyze the MOA-2020-BLG-208 gravitational microlensing event and present the discovery and characterization of a new planet, MOA-2020-BLG-208Lb, with an estimated sub-Saturn mass. With a mass ratio $q = 3.17^{+0.28}_{-0.26} \times 10^{-4}$ and a separation $s = 1.3807^{+0.0018}_{-0.0018}$, the planet lies near the peak of the mass-ratio function derived by the MOA collaboration (Suzuki et al. 2016), near the edge of expected sample sensitivity. For these estimates we provide results using two mass law priors: one assuming that all stars have an equal planet-hosting probability, and the other assuming that planets are more likely to orbit around more massive stars. In the first scenario, we estimate that the lens system is likely to be a planet of mass $m_\mathrm{planet} = 46^{+42}_{-24} \; M_\oplus$ and a host star of mass $M_\mathrm{host} = 0.43^{+0.39}_{-0.23} \; M_\odot$, located at a distance $D_L = 7.49^{+0.99}_{-1.13} \; \mathrm{kpc}$. For the second scenario, we estimate $m_\mathrm{planet} = 69^{+37}_{-34} \; M_\oplus$, $M_\mathrm{host} = 0.66^{+0.35}_{-0.32} \; M_\odot$, and $D_L = 7.81^{+0.93}_{-0.93} \; \mathrm{kpc}$. As a cool sub-Saturn-mass planet, this planet adds to a growing collection of evidence for revised planetary formation models and qualifies for inclusion in the extended MOA-II exoplanet microlensing sample.

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Greg Olmschenk, David P. Bennett, Ian A. Bond, Weicheng Zang, Youn Kil Jung, Jennifer C. Yee, Etienne Bachelet, Fumio Abe, Richard K. Barry, Aparna Bhattacharya, Hirosane Fujii, Akihiko Fukui, Yuki Hirao, Stela Ishitani Silva, Yoshitaka Itow, Rintaro Kirikawa, Iona Kondo, Naoki Koshimoto, Yutaka Matsubara, Sho Matsumoto, Shota Miyazaki, Brandon Munford, Yasushi Muraki, Arisa Okamura, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Takahiro Sumi, Daisuke Suzuki, Taiga Toda, Paul J. Tristram, Katie Vandorou, Hibiki Yama, Michael D. Albrow, Sang-Mok Cha, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Grant Christie, Tony Cooper, John Drummond, Jonathan Green, Steve Hennerley, Jennie McCormick, L. A. G. Monard, Tim Natusch, Ian Porritt, Thiam-Guan Tan, Shude Mao, Dan Maoz, Matthew T. Penny, Wei Zhu, V. Bozza, Arnaud Cassan, Martin Dominik, Markus Hundertmark, R. Figuera Jaimes, K. Kruszyńska, K. A. Rybicki, R. A. Street, Y. Tsapras, Joachim Wambsganss, Ł. Wyrzykowski, P. Zieliński, Gioia Rau. 2022-10-05. MOA-2020-BLG-208Lb: Cool Sub-Saturn Planet Within Predicted Desert. https://doi.org/10.3847/1538-3881/acbcc8

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