Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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KMT-2018-BLG-0029LB: A VERY LOW MASS-RATIO Spitzer MICROLENS PLANET

  • Gould, Andrew (Max-Planck-Institute for Astronomy) ;
  • Ryu, Yoon-Hyun (Korea Astronomy and Space Science Institute) ;
  • Novati, Sebastiano Calchi (IPAC) ;
  • Zang, Weicheng (Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University) ;
  • Albrow, Michael D. (University of Canterbury, Department of Physics and Astronomy) ;
  • Chung, Sun-Ju (Korea Astronomy and Space Science Institute) ;
  • Han, Cheongho (Department of Physics, Chungbuk National University) ;
  • Hwang, Kyu-Ha (Korea Astronomy and Space Science Institute) ;
  • Jung, Youn Kil (Korea Astronomy and Space Science Institute) ;
  • Shin, In-Gu (Korea Astronomy and Space Science Institute) ;
  • Shvartzvald, Yossi (IPAC) ;
  • Yee, Jennifer C. (Center for Astrophysics / Harvard & Smithsonian) ;
  • Cha, Sang-Mok (Korea Astronomy and Space Science Institute) ;
  • Kim, Dong-Jin (Korea Astronomy and Space Science Institute) ;
  • Kim, Hyoun-Woo (Korea Astronomy and Space Science Institute) ;
  • Kim, Seung-Lee (Korea Astronomy and Space Science Institute) ;
  • Lee, Chung-Uk (Korea Astronomy and Space Science Institute) ;
  • Lee, Dong-Joo (Korea Astronomy and Space Science Institute) ;
  • Lee, Yongseok (Korea Astronomy and Space Science Institute) ;
  • Park, Byeong-Gon (Korea Astronomy and Space Science Institute) ;
  • Pogge, Richard W. (Department of Astronomy Ohio State University) ;
  • Beichman, Charles (NASA Exoplanet Science Institute, California Institute of Technology) ;
  • Bryden, Geoff (IPAC) ;
  • Carey, Sean (Spitzer, Science Center) ;
  • Gaudi, B. Scott (Department of Astronomy Ohio State University) ;
  • Henderson, Calen B. (IPAC) ;
  • Zhu, Wei (Canadian Institute for Theoretical Astrophysics, University of Toronto) ;
  • Fouque, Pascal (CFHT Corporation) ;
  • Penny, Matthew T. (Department of Astronomy Ohio State University) ;
  • Petric, Andreea (CFHT Corporation) ;
  • Burdullis, Todd (CFHT Corporation) ;
  • Mao, Shude (Department of Astronomy and Tsinghua Centre for Astrophysics, Tsinghua University)
  • Received : 2019.06.27
  • Accepted : 2019.12.31
  • Published : 2020.02.29
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Abstract

At q = 1.81 ± 0.20 × 10-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10 ×10-5. The event was observed by Spitzer, yielding a microlens-parallax πE measurement. Combined with a measurement of the Einstein radius θE from finite-source effects during the caustic crossings, these measurements imply masses of the host Mhost = 1.14+0.10-0.12 M⊙ and planet Mplanet = 7.59+0.75-0.69 M⊕, system distance DL = 3.38+0.22-0.26 kpc and projected separation a⊥ = 4.27+0.21-0.23 AU. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.

Keywords

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