Volume 649, May 2021
|Number of page(s)||10|
|Section||Planets and planetary systems|
|Published online||18 May 2021|
KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star★
Department of Physics, Chungbuk National University,
Republic of Korea
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 University of Canterbury, Department of Physics and Astronomy, 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 and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084, PR China
11 School of Space Research, Kyung Hee University, Yongin, Kyeonggi 17104, Republic of Korea
12 Department of Astronomy & Space Science, Chungbuk National University, Cheongju 28644, Republic of Korea
13 Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
14 Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
15 Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
Accepted: 3 February 2021
Aims. We aim to find missing microlensing planets hidden in the unanalyzed lensing events of previous survey data.
Methods. For this purpose, we conducted a systematic inspection of high-magnification microlensing events, with peak magnifications of Apeak ≳ 30, in the data collected from high-cadence surveys in and before the 2018 season. From this investigation, we identified an anomaly in the lensing light curve of the event KMT-2018-BLG-1025. The analysis of the light curve indicates that the anomaly is caused by a very low mass-ratio companion to the lens.
Results. We identify three degenerate solutions, in which the ambiguity between a pair of solutions (solutions B) is caused by the previously known close–wide degeneracy, and the degeneracy between these and the other solution (solution A) is a new type that has not been reported before. The estimated mass ratio between the planet and host is q ~ 0.8 × 10−4 for solution A and q ~ 1.6 × 10−4 for solutions B. From the Bayesian analysis conducted with measured observables, we estimate that the masses of the planet and host and the distance to the lens are (Mp, Mh, DL) ~ (6.1 M⊕, 0.22 M⊙, 6.7 kpc) for solution A and ~(4.4 M⊕, 0.08 M⊙, 7.5 kpc) for solutions B. The planet mass is in the category of a super-Earth regardless of the solutions, making the planet the eleventh super-Earth planet, with masses lying between those of Earth and the Solar System’s ice giants, which were discovered by microlensing.
Key words: gravitational lensing: micro / planets and satellites: general
Photometric data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/649/A90
© ESO 2021
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.