Authors

Yoon Hyun Ryu, Korea Astronomy and Space Science Institute
Andrzej Udalski, Uniwersytet Warszawski
Jennifer C. Yee, Harvard-Smithsonian Center for Astrophysics
Matthew T. Penny, The Ohio State University
Weicheng Zang, Tsinghua University
Michael D. Albrow, University of Canterbury
Sun Ju Chung, Korea Astronomy and Space Science Institute
Andrew Gould, The Ohio State University
Cheongho Han, Chungbuk National University
Kyu Ha Hwang, Korea Astronomy and Space Science Institute
Youn Kil Jung, Korea Astronomy and Space Science Institute
In Gu Shin, Korea Astronomy and Space Science Institute
Yossi Shvartzvald, Infrared Processing & Analysis Center
Sang Mok Cha, Korea Astronomy and Space Science Institute
Dong Jin Kim, Korea Astronomy and Space Science Institute
Hyoun Woo Kim, Korea Astronomy and Space Science Institute
Seung Lee Kim, Korea Astronomy and Space Science Institute
Chung Uk Lee, Korea Astronomy and Space Science Institute
Dong Joo Lee, Korea Astronomy and Space Science Institute
Yongseok Lee, Korea Astronomy and Space Science Institute
Byeong Gon Park, Korea Astronomy and Space Science Institute
Richard W. Pogge, The Ohio State University
Przemek Mróz, Uniwersytet Warszawski
Michał K. Szymański, Uniwersytet Warszawski
Jan Skowron, Uniwersytet Warszawski
Radek Poleski, The Ohio State University
Igor Soszyński, Uniwersytet Warszawski
Paweł Pietrukowicz, Uniwersytet Warszawski
Szymon Kozłowski, Uniwersytet Warszawski
Krzysztof Ulaczyk, University of Warwick
Krzysztof A. Rybicki, Uniwersytet Warszawski
Patryk Iwanek, Uniwersytet Warszawski
Marcin Wrona, Uniwersytet Warszawski

Document Type

Article

Publication Date

10-1-2020

Abstract

We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio q = Mplanet Mhost ≃ 1 ´ 10-4. Although there are no obvious systematic residuals to this double-lens/single-source (2L1S) fit, we find that χ2 can be significantly improved by adding either a third lens (3L1S, Δχ2 = 81) or second source (2L2S, Δχ2 = 77) to the lens-source geometry. After thorough investigation, we conclude that we cannot decisively distinguish between these two scenarios and therefore focus on the robustly detected planet. However, given the possible presence of a second planet, we investigate to what degree and with what probability such additional planets may affect seemingly single-planet light curves. Our best estimates for the properties of the lens star and the secure planet are a host mass M ∼ 0.25 Me, system distance DL ∼ 1 kpc, and planet mass mp,1 = 8 MÅ with projected separation a1^ = 1.4 au. However, there is a relatively bright I = 18.6 (and also relatively blue) star projected within lens, and if future high-resolution images show that this is coincident with the lens, then it is possible that it is the lens, in which case, the lens would be both more massive and more distant than the best-estimated values above.

Publication Source (Journal or Book title)

Astronomical Journal

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