KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal
Creators: name: Han, Cheongho
name: Jung, Youn Kil
name: Bond, Ian A.
name: Gould, Andrew
name: Chung, Sun-Ju
name: Albrow, Michael D.
name: Hwang, Kyu-Ha
name: Ryu, Yoon-Hyun
name: Shin, In-Gu
name: Shvartzvald, Yossi
name: Yang, Hongjing
name: Yee, Jennifer C.
name: Zang, Weicheng
name: Cha, Sang-Mok
name: Kim, Doeon
name: Kim, Dong-Jin
name: Kim, Seung-Lee
name: Lee, Chung-Uk
name: Lee, Dong-Joo
name: Lee, Yongseok
name: Park, Byeong-Gon
name: Pogge, Richard W.
name: Abe, Fumio
name: Barry, Richard
name: Bennett, David P.
name: Bhattacharya, Aparna
name: Fujii, Hirosame
name: Fukui, Akihiko
name: Hamada, Ryusei
name: Hirao, Yuki
name: Silva, Stela Ishitani
name: Itow, Yoshitaka
name: Kirikawa, Rintaro
name: Kondo, Iona
name: Koshimoto, Naoki
name: Matsubara, Yutaka
name: Matsumoto, Sho
name: Miyazaki, Shota
name: Muraki, Yasushi
name: Okamura, Arisa
name: Olmschenk, Greg
name: Ranc, Clément
name: Rattenbury, Nicholas J.
name: Satoh, Yuki
name: Sumi, Takahiro
name: Suzuki, Daisuke
name: Toda, Taiga
name: Tomoyoshi, Mio
name: Tristram, Paul J.
name: Vandorou, Aikaterini
name: Yama, Hibiki
name: Yamashita, Kansuke
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Recently, there have been reports of various types of degeneracies in the interpretation of planetary signals induced by planetary caustics. In this work, we check whether such degeneracies persist in the case of well-covered signals by analyzing the lensing event KMT-2021-BLG-1150, for which the light curve exhibits a densely and continuously covered short-term anomaly. In order to identify degenerate solutions, we thoroughly investigate the parameter space by conducting dense grid searches for the lensing parameters. We then check the severity of the degeneracy among the identified solutions. We identify a pair of planetary solutions resulting from the well-known inner-outer degeneracy, and find that interpreting the anomaly is not subject to any degeneracy other than the inner-outer degeneracy. The measured parameters of the planet separation (normalized to the Einstein radius) and mass ratio between the lens components are $(s, q)_{\rm in}\sim (1.297, 1.10\times 10^{-3})$ for the inner solution and $(s, q)_{\rm out}\sim (1.242, 1.15\times 10^{-3})$ for the outer solution. According to a Bayesian estimation, the lens is a planetary system consisting of a planet with a mass $M_{\rm p}=0.88^{+0.38}_{-0.36}~M_{\rm J}$ and its host with a mass $M_{\rm h}=0.73^{+0.32}_{-0.30}~M_\odot$ lying toward the Galactic center at a distance $D_{\rm L} =3.8^{+1.3}_{-1.2}$~kpc. By conducting analyses using mock data sets prepared to mimic those obtained with data gaps and under various observational cadences, it is found that gaps in data can result in various degenerate solutions, while the observational cadence does not pose a serious degeneracy problem as long as the anomaly feature can be delineated.
description: 9 pages, 8 figures