Systematic KMTNet Planetary Anomaly Search. I. OGLE-2019-BLG-1053Lb, a Buried Terrestrial Planet

Journal Article · Fri Oct 01 04:00:00 EDT 2021 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AC12D4· OSTI ID:23159382

Zang, Weicheng; Zhu, Wei; Mao, Shude; Zhang, Xiangyu ^[1]; Hwang, Kyu-Ha; Chung, Sun-Ju; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo ^[2]; Udalski, Andrzej ^[3]; Wang, Tianshu ^[4]; Sumi, Takahiro ^[5]; Yee, Jennifer C. ^[6]; Gould, Andrew ^[7]; Albrow, Michael D. ^[8]; Han, Cheongho ^[9]; Shvartzvald, Yossi ^[10] ; others, and

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1. Department of Astronomy, Tsinghua University, Beijing 100084 (China)
2. Korea Astronomy and Space Science Institute, Daejon 34055 (Korea, Republic of)
3. Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
4. Department of Astrophysical Sciences, Princeton University (United States)
5. Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
6. Center for Astrophysics - Harvard & Smithsonian, 60 Garden St.,Cambridge, MA 02138 (United States)
7. Max-Planck-Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
8. University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020 (New Zealand)
9. Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of)
10. Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)

In order to exhume the buried signatures of “missing planetary caustics” in Korea Microlensing Telescope Network (KMTNet) data, we conducted a systematic anomaly search of the residuals from point-source point-lens fits, based on a modified version of the KMTNet EventFinder algorithm. This search revealed 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 ± 0.13) × 10{sup -5}. A Bayesian analysis yielded estimates of the mass of the host star, M{sub host}=0.61{sub -0.24}{sup +0.29} M{sub ⊙}, the mass of its planet, M{sub planet}=2.48{sub -0.98}{sup +1.19} M{sub ⊕}, the projected planet–host separation, a{sub ⊥}=3.4{sub -0.5}{sup +0.5} au, and the lens distance, D{sub L}=6.8{sub -0.9}{sup +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 ~ 10{sup -5}.

• OSTI ID: 23159382
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 4 Vol. 162; ISSN 1538-3881
• Country of Publication: United States
• Language: English

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