Systematic KMTNet Planetary Anomaly Search, Paper I: OGLE-2019-BLG-1053Lb, A Buried Terrestrial Planet

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Weicheng Zang Kyu-Ha Hwang Andrzej Udalski Tianshu Wang Wei Zhu Takahiro Sumi Jennifer C. Yee Andrew Gould Shude Mao Xiangyu Zhang Michael D. Albrow Sun-Ju Chung Cheongho Han Youn Kil Jung Yoon-Hyun Ryu In-Gu Shin Yossi Shvartzvald Sang-Mok Cha Dong-Jin Kim Hyoun-Woo Kim

摘要： In order to exhume the buried signatures of "missing planetary caustics" in the KMTNet data, we conducted a systematic anomaly search to the residuals from point-source point-lens fits, based on a modified version of the KMTNet EventFinder algorithm. This search reveals the lowest mass-ratio planetary caustic to date in the microlensing event OGLE-2019-BLG-1053, for which the planetary signal had not been noticed before. The planetary system has a planet-host mass ratio of $q = (1.25 \pm 0.13) \times 10^{-5}$. A Bayesian analysis yields estimates of the mass of the host star, $M_{\rm host} = 0.61_{-0.24}^{+0.29}~M_\odot$, the mass of its planet, $M_{\rm planet} = 2.48_{-0.98}^{+1.19}~M_{\oplus}$, the projected planet-host separation, $a_\perp = 3.4_{-0.5}^{+0.5}$ au, and the lens distance of $D_{\rm L} = 6.8_{-0.9}^{+0.6}$ kpc. The discovery of this very low mass-ratio planet illustrates the utility of our method and opens a new window for a large and homogeneous sample to study the microlensing planet-host mass-ratio function down to $q \sim 10^{-5}$.

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