OGLE-2023-BLG-0836L: The sixth microlensing planet in a binary stellar system
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk; Zang, Weicheng; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Hwang, Kyu-Ha; Jung, Youn Kil; Ryu, Yoon-Hyun; Shvartzvald, Yossi; Shin, In-Gu; Yee, Jennifer C.; Yang, Hongjing; Cha, Sang-Mok; Kim, Doeon; Kim, Dong-Jin; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radosław; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Rybicki, Krzysztof A.; Iwanek, Patryk; Ulaczyk, Krzysztof; Wrona, Marcin; Gromadzki, Mariusz; Mróz, Mateusz J.
Poland, Israel, United Kingdom
Abstract
Aims: Light curves of microlensing events occasionally deviate from the smooth and symmetric form of a single-lens single-source event. While most of these anomalous events can be accounted for by employing a binary-lens single-source (2L 1S) or a single-lens binary-source (1L2S) framework, it is established that a small fraction of events remain unexplained by either of these interpretations. We carried out a project in which data collected by high-cadence microlensing surveys were reinvestigated with the aim of uncovering the nature of anomalous lensing events with no proposed 2L 1S or 1L 2S models.
Methods: From the project we found that the anomaly appearing in the lensing event OGLE-2023-BLG-0836 cannot be explained by the usual interpretations, and we conducted a comprehensive analysis of the event. From thorough modeling of the light curve under sophisticated lens-system configurations, we arrived at the conclusion that a triple-mass lens system is imperative to account for the anomalous features observed in the lensing light curve.
Results: From the Bayesian analysis using the measured observables of the event timescale and angular Einstein radius, we determined that the least massive component of the lens has a planetary mass of 4.36−2.18+2.35 MJ. This planet orbits within a stellar binary system composed of two stars with masses 0.71−0.36+0.38 M⊙ and 0.56−0.28+0.30 M⊙. This lensing event signifies the sixth occurrence of a planetary microlensing system in which a planet belongs to a stellar binary system.