Three microlensing planets with no caustic-crossing features

¹ Department of Physics, Chungbuk National University, Cheongju 28644, Republic of Korea
e-mail: cheongho@astroph.chungbuk.ac.kr
² Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
³ Korea Astronomy and Space Science Institute, Daejon 34055, Republic of Korea
⁴ Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
⁵ Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
⁶ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁷ Department of Astronomy, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, USA
⁸ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
⁹ Center for Astrophysics, Harvard & Smithsonian 60 Garden St., Cambridge, MA 02138, USA
¹⁰ Department of Astronomy, Tsinghua University, Beijing 100084, PR China
¹¹ School of Space Research, Kyung Hee University, Yongin, Kyeonggi 17104, Republic of Korea
¹² Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
¹³ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK

Received: 9 March 2021
Accepted: 13 April 2021

Abstract

Aims. We search for microlensing planets with signals exhibiting no caustic-crossing features, considering the possibility that such signals may be missed due to their weak and featureless nature.

Methods. For this purpose, we reexamine the lensing events found by the KMTNet survey before the 2019 season. From this investigation, we find two new planetary lensing events, KMT-2018-BLG-1976 and KMT-2018-BLG-1996. We also present the analysis of the planetary event OGLE-2019-BLG-0954, for which the planetary signal was known but no detailed analysis had previously been presented. We identify the genuineness of the planetary signals by checking various interpretations that can generate short-term anomalies in lensing light curves.

Results. From Bayesian analyses conducted with the constraint from available observables, we find that the host and planet masses are (M₁, M₂) ~ (0.65 M_⊙, 2 M_J) for KMT-2018-BLG-1976L, ~(0.69 M_⊙, 1 M_J) for KMT-2018-BLG-1996L, and ~(0.80 M_⊙, 14 M_J) for OGLE-2019-BLG-0954L. The estimated distance to OGLE-2019-BLG-0954L, 3.63_−1.64^+1.22 kpc, indicates that it is located in the disk, and the brightness expected from the mass and distance matches the brightness of the blend well, indicating that the lens accounts for most of the blended flux. The lens of OGLE-2019-BLG-0954 may be resolved from the source by conducting high-resolution follow-up observations in and after 2024.