KMT-2022-BLG-0440Lb: A new q &lt; 10<SUP>-4</SUP> microlensing planet with the central-resonant caustic degeneracy broken

Zhang, Jiyuan; Zang, Weicheng; Jung, Youn Kil; Yang, Hongjing; Gould, Andrew; Sumi, Takahiro; Mao, Shude; Dong, Subo; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Qian, Qiyue; Liu, Zhuokai; Maoz, Dan; Penny, Matthew T.; Zhu, Wei; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Bond, Ian A.; Fujii, Hirosane; Fukui, Akihiko; Hamada, Ryusei; Hirao, Yuki; Silva, Stela Ishitani; Itow, Yoshitaka; Kirikawa, Rintaro; Kondo, Iona; Koshimoto, Naoki; Matsubara, Yutaka; Matsumoto, Sho; Miyazaki, Shota; Muraki, Yasushi; Okamura, Arisa; Olmschenk, Greg; Ranc, Clément; Rattenbury, Nicholas J.; Satoh, Yuki; Suzuki, Daisuke; Toda, Taiga; Tomoyoshi, Mio; Tristram, Paul J.; Vandorou, Aikaterini; Yama, Hibiki; Yamashita, Kansuke; MOA Collaboration
Bibliographical reference

Monthly Notices of the Royal Astronomical Society

Advertised on:
7
2023
Number of authors
61
IAC number of authors
1
Citations
3
Refereed citations
1
Description
We present the observations and analysis of a high-magnification microlensing planetary event, KMT-2022-BLG-0440, for which the weak and short-lived planetary signal was covered by both the KMTNet survey and follow-up observations. The binary-lens models with a central caustic provide the best fits, with a planet/host mass ratio, q = 0.75-1.00 × 10-4 at 1σ. The binary-lens models with a resonant caustic and a brown-dwarf mass ratio are both excluded by Δχ2 > 70. The binary-source model can fit the anomaly well but is rejected by the 'colour argument' on the second source. From Bayesian analyses, it is estimated that the host star is likely a K or M dwarf located in the Galactic disc, the planet probably has a Neptune-mass, and the projected planet-host separation is $1.9^{+0.6}_{-0.7}$ or $4.6^{+1.4}_{-1.7}$ au, subject to the close/wide degeneracy. This is the third q < 10-4 planet from a high-magnification planetary signal (A ≳ 65). Together with another such planet, KMT-2021-BLG-0171Lb, the ongoing follow-up program for the KMTNet high-magnification events has demonstrated its ability to detect high-magnification planetary signals for q < 10-4 planets, which are challenging for the current microlensing surveys.