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Journal Articles Research in Astronomy and Astrophysics Year : 2021

An Earth-mass planet in a time of COVID-19: KMT-2020-BLG-0414Lb

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Weicheng Zang
  • Function : Author
Cheongho Han
  • Function : Author
Iona Kondo
Jennifer C. Yee
  • Function : Author
Chung-Uk Lee
  • Function : Author
Andrew Gould
Shude Mao
  • Function : Author
Leandro de Almeida
  • Function : Author
Yossi Shvartzvald
  • Function : Author
Xiangyu Zhang
  • Function : Author
Michael D. Albrow
  • Function : Author
Sun-Ju Chung
  • Function : Author
Kyu-Ha Hwang
  • Function : Author
Youn Kil Jung
  • Function : Author
Yoon-Hyun Ryu
  • Function : Author
In-Gu Shin
  • Function : Author
Sang-Mok Cha
  • Function : Author
Dong-Jin Kim
  • Function : Author
Hyoun-Woo Kim
  • Function : Author
Seung-Lee Kim
  • Function : Author
Dong-Joo Lee
  • Function : Author
Yongseok Lee
  • Function : Author
Byeong-Gon Park
  • Function : Author
Richard W. Pogge
  • Function : Author
John Drummond
  • Function : Author
Thiam-Guan Tan
Dan Maoz
  • Function : Author
Matthew T. Penny
  • Function : Author
Wei Zhu
  • Function : Author
Ian A. Bond
  • Function : Author
Fumio Abe
  • Function : Author
Richard Barry
  • Function : Author
David P. Bennett
  • Function : Author
Aparna Bhattacharya
  • Function : Author
Martin Donachie
  • Function : Author
Hirosane Fujii
  • Function : Author
Akihiko Fukui
Yuki Hirao
  • Function : Author
Yoshitaka Itow
Rintaro Kirikawa
  • Function : Author
Naoki Koshimoto
Man Cheung Alex Li
  • Function : Author
Yutaka Matsubara
  • Function : Author
Yasushi Muraki
Shota Miyazaki
Greg Olmschenk
Clément Ranc
  • Function : Author
  • PersonId : 1181264
  • IdHAL : cr
Nicholas J. Rattenbury
  • Function : Author
Yuki Satoh
  • Function : Author
Hikaru Shoji
  • Function : Author
Stela Ishitani Silva
  • Function : Author
Takahiro Sumi
Daisuke Suzuki
Yuzuru Tanaka
  • Function : Author
Paul J. Tristram
  • Function : Author
Tsubasa Yamawaki
  • Function : Author
Atsunori Yonehara
  • Function : Author
Todd Burdullis
  • Function : Author

Abstract

We report the discovery of KMT-2020-BLG-0414Lb, with a planet-to-host mass ratio q2 = 0.9-1.2 × 10-5 = 3-4 ⊕ at 1σ, which is the lowest mass-ratio microlensing planet to date. Together with two other recent discoveries (4 ≲ q/q ≲ 6), it fills out the previous empty sector at the bottom of the triangular (log s, log q) diagram, where s is the planet-host separation in units of the angular Einstein radius θE. Hence, these discoveries call into question the existence, or at least the strength, of the break in the mass-ratio function that was previously suggested to account for the paucity of very low-q planets. Due to the extreme magnification of the event, Amax ~ 1450 for the underlying single-lens event, its light curve revealed a second companion with q3 ~ 0.05 and |log s3| ~ 1, i.e., a factor ~ 10 closer to or farther from the host in projection. The measurements of the microlens parallax πE and the angular Einstein radius θE allow estimates of the host, planet and second companion masses, (M1, M2, M3) ~ (0.3 M, 1.0 M, 17 MJ), the planet and second companion projected separations, (a⊥,2, a⊥,3) ~ (1.5, 0.15 or 15) au, and system distance DL ~ 1 kpc. The lens could account for most or all of the blended light (I ~ 19.3) and so can be studied immediately with high-resolution photometric and spectroscopic observations that can further clarify the nature of the system. The planet was found as part of a new program of high-cadence follow-up observations of high-magnification events. The detection of this planet, despite the considerable difficulties imposed by COVID-19 (two KMT sites and OGLE were shut down), illustrates the potential utility of this program.

Dates and versions

insu-03672352 , version 1 (19-05-2022)

Identifiers

Cite

Weicheng Zang, Cheongho Han, Iona Kondo, Jennifer C. Yee, Chung-Uk Lee, et al.. An Earth-mass planet in a time of COVID-19: KMT-2020-BLG-0414Lb. Research in Astronomy and Astrophysics, 2021, 21, ⟨10.1088/1674-4527/21/9/239⟩. ⟨insu-03672352⟩
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