KMT-2023-BLG-1431Lb: A New $q < 10^{-4}$ Microlensing Planet from a Subtle Signature

• DOI: 10.48550/arxiv.2311.13097
• Publication Date: 2023-01-01
• Authors: Aislyn Bell; Jiyuan Zhang; Youn Kil Jung; Jennifer C. Yee; Hongjing Yang; Takahiro Sumi; A. Udalski; Michael D. Albrow; Sun‐Ju Chung; Andrew Gould; Cheongho Han; Kyu‐Ha Hwang; Yoon-Hyun Ryu; In-Gu Shin; Yossi Shvartzvald; Weicheng Zang; Sang-Mok Cha; Dong-Jin Kim; Seung‐Lee Kim; Chung‐Uk Lee; Dong-Joo Lee; Yongseok Lee; Byeong-Gon Park; Richard W. Pogge; Yunyi Tang; J. McCormick; Subo Dong; Zhuokai Liu; Shude Mao; Dan Maoz; Wei Zhu; Fumio Abe; Richard Barry; D. P. Bennett; Aparna Bhattacharya; I. A. Bond; Hirosane Fujii; Akihiko Fukui; Ryusei Hamada; Yuki Hirao; Stela Ishitani Silva; Y. Itow; Rintaro Kirikawa; Iona Kondo; Naoki Koshimoto; Y. Matsubara; Sho Matsumoto; Shota Miyazaki; Y. Muraki; Arisa Okamura; Greg Olmschenk; ‪Clément Ranc; Nicholas J. Ratte...; Yuki Satoh; D. Suzuki; Taiga Toda; Mio Tomoyoshi; P. J. Tristram; Aikaterini Vandorou; Hibiki Yama; Kansuke Yamashita; P. Mróz; J. Skowron; R. Poleski; M. K. Szymański; I. Soszyński; P. Pietrukowicz; S. Kozłowski; K. Ulaczyk; K. Rybicki; Patryk Iwanek; Marcin Wrona; M. Gromadzki
• Keywords: Gravitational microlensing; Degeneracy (biology); Mass ratio

The current studies of microlensing planets are limited by small number statistics. Follow-up observations high-magnification events can efficiently form a statistical planetary sample. Since 2020, the Korea Microlensing Telescope Network (KMTNet) and Las Cumbres Observatory (LCO) global network have been conducting follow-up program for KMTNet events. Here, we report detection analysis event, KMT-2023-BLG-1431, which subtle (0.05 magnitude) short-lived (5 hours) signature was characterized from LCO. A binary-lens single-source (2L1S) reveals planet/host mass ratio $q = (0.72 \pm 0.07) \times 10^{-4}$, single-lens binary-source (1L2S) model is excluded $\Delta\chi^2 80$. Bayesian using Galactic yields estimates host star $M_{\rm host} 0.57^{+0.33}_{-0.29}~M_\odot$, planet} 13.5_{-6.8}^{+8.1}~M_{\oplus}$, lens distance $D_{\rm L} 6.9_{-1.7}^{+0.8}$ kpc. projected planet-host separation $a_\perp 2.3_{-0.5}^{+0.5}$ au or 3.2_{-0.8}^{+0.7}$, subject to close/wide degeneracy. We also find that without data, survey-only data cannot break degeneracy central/resonant caustics 2L1S/1L2S models, showing importance surveys.