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

October 2021 • 2021AJ....162..163Z

Authors • Zang, Weicheng • Hwang, Kyu-Ha • Udalski, Andrzej • Wang, Tianshu • Zhu, Wei • Sumi, Takahiro • Yee, Jennifer C. • Gould, Andrew • Mao, Shude • Zhang, Xiangyu • Albrow, Michael D. • Chung, Sun-Ju • Han, Cheongho • Jung, Youn Kil • Ryu, Yoon-Hyun • Shin, In-Gu • Shvartzvald, Yossi • Cha, Sang-Mok • Kim, Dong-Jin • Kim, Hyoun-Woo • Kim, Seung-Lee • Lee, Chung-Uk • Lee, Dong-Joo • Lee, Yongseok • Park, Byeong-Gon • Pogge, Richard W. • Mróz, Przemek • Skowron, Jan • Poleski, Radoslaw • Szymański, Michał K. • Soszyński, Igor • Pietrukowicz, Paweł • Kozłowski, Szymon • Ulaczyk, Krzysztof • Rybicki, Krzysztof A. • Iwanek, Patryk • Wrona, Marcin • Gromadzki, Mariusz • Bond, Ian A. • Abe, Fumio • Barry, Richard • Bennett, David P. • Bhattacharya, Aparna • Donachie, Martin • Fujii, Hirosane • Fukui, Akihiko • Hirao, Yuki • Itow, Yoshitaka • Kirikawa, Rintaro • Kondo, Iona • Koshimoto, Naoki • Li, Man Cheung Alex • Matsubara, Yutaka • Muraki, Yasushi • Miyazaki, Shota • Olmschenk, Greg • Ranc, Clément • Rattenbury, Nicholas J. • Satoh, Yuki • Shoji, Hikaru • Ishitani Silva, Stela • Suzuki, Daisuke • Tanaka, Yuzuru • Tristram, Paul J. • Yamawaki, Tsubasa • Yonehara, Atsunori • Beichman, Charles A. • Bryden, Geoffery • Calchi Novati, Sebastiano • Carey, Sean • Gaudi, B. Scott • Henderson, Calen B. • Johnson, Samson • Spitzer Team

Abstract • 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^-5. A Bayesian analysis yielded estimates of the mass of the host star, ${M}_{\mathrm{host}}={0.61}_{-0.24}^{+0.29}\,{M}_{\odot }$ , the mass of its planet, ${M}_{\mathrm{planet}}={2.48}_{-0.98}^{+1.19}\,{M}_{\oplus }$ , the projected planet-host separation, ${a}_{\perp }={3.4}_{-0.5}^{+0.5}$ au, and the lens distance, ${D}_{{\rm{L}}}={6.8}_{-0.9}^{+0.6}$ 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 ~ 10^-5.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2021AJ....162..163Z
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/163
• PREPRINT http://arxiv.org/abs/2103.11880
• ELECTR https://doi.org/10.3847%2F1538-3881%2Fac12d4