Issue |
A&A
Volume 678, October 2023
|
|
---|---|---|
Article Number | A101 | |
Number of page(s) | 9 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202347366 | |
Published online | 13 October 2023 |
KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed due to source binarity
1
Department of Physics, Chungbuk National University,
Cheongju
28644,
Republic of Korea
e-mail: cheongho@astroph.chungbuk.ac.kr
2
Center for Astrophysics | Harvard & Smithsonian,
60 Garden St.,
Cambridge, MA
02138,
USA
3
Department of Astronomy, Tsinghua University,
Beijing
100084,
PR China
4
Korea Astronomy and Space Science Institute,
Daejon
34055,
Republic of Korea
5
Korea University of Science and Technology, Korea, (UST),
217 Gajeong-ro,
Yuseong-gu, Daejeon
34113,
Republic of Korea
6
Institute of Natural and Mathematical Science, Massey University,
Auckland
0745,
New Zealand
7
University of Canterbury, Department of Physics and Astronomy,
Private Bag 4800,
Christchurch
8020,
New Zealand
8
Max-Planck-Institute for Astronomy,
Königstuhl 17,
69117
Heidelberg,
Germany
9
Department of Astronomy, Ohio State University,
140 W. 18th Ave.,
Columbus, OH
43210,
USA
10
Department of Particle Physics and Astrophysics, Weizmann Institute of Science,
Rehovot
76100,
Israel
11
School of Space Research, Kyung Hee University, Yongin,
Kyeonggi
17104,
Republic of Korea
12
Klein Karoo Observatory, Calitzdorp, and Bronberg Observatory,
Pretoria,
South Africa
13
Kavli Institute for Astronomy and Astrophysics, Peking University,
Yi He Yuan Road 5, Hai Dian District,
Beijing
100871,
PR China
14
School of Physics and Astronomy, Tel-Aviv University,
Tel-Aviv
6997801,
Israel
15
Department of Physics and Astronomy, Louisiana State University,
Baton Rouge, LA
70803,
USA
16
Institute for Space-Earth Environmental Research, Nagoya University,
Nagoya
464-8601,
Japan
17
Code 667, NASA Goddard Space Flight Center,
Greenbelt, MD
20771,
USA
18
Department of Astronomy, University of Maryland,
College Park, MD
20742,
USA
19
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
7-3-1 Hongo,
Bunkyo-ku, Tokyo
113-0033,
Japan
20
Instituto de Astrofisica de Canarias,
Via Lâctea s/n,
38205
La Laguna, Tenerife,
Spain
21
Department of Earth and Space Science, Graduate School of Science, Osaka University,
Toyonaka, Osaka
560-0043,
Japan
22
Institute of Astronomy, Graduate School of Science, The University of Tokyo,
2-21-1 Osawa,
Mitaka, Tokyo
181-0015,
Japan
23
Department of Physics, The Catholic University of America,
Washington, DC
20064,
USA
24
Department of Astronomy, Graduate School of Science, The University of Tokyo,
7-3-1 Hongo,
Bunkyo-ku, Tokyo
113-0033,
Japan
25
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency,
3-1-1 Yoshinodai, Chuo,
Sagamihara, Kanagawa
252-5210,
Japan
26
Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris,
98 bis bd Arago,
75014
Paris,
France
27
Department of Physics, University of Auckland,
Private Bag
92019,
Auckland,
New Zealand
28
University of Canterbury Mt. John Observatory,
PO Box 56,
Lake Tekapo
8770,
New Zealand
Received:
5
July
2023
Accepted:
31
August
2023
Aims. We investigate the previous microlensing data collected by the KMTNet survey in search of anomalous events for which no precise interpretations of the anomalies had been suggested. From this investigation, we find that the anomaly in the lensing light curve of the event KMT-2021-BLG-1547 is approximately described by a binary-lens (2L1S) model with a lens possessing a giant planet, but the model leaves unexplained residuals.
Methods. We investigated the origin of the residuals by testing more sophisticated models that include either an extra lens component (3L1S model) or an extra source star (2L2S model) on top of the 2L1S configuration of the lens system. From these analyses, we find that the residuals from the 2L1S model originate from the existence of a faint companion to the source. The 2L2S solution substantially reduces the residuals and improves the model fit by Δχ2 = 67.1 with respect to the 2L1S solution. The 3L1S solution also improves the fit, but its fit is worse than that of the 2L2S solution by Δχ2 = 24.7.
Results. According to the 2L2S solution, the lens of the event is a planetary system with planet and host masses (Mp/MJ, Mh/M⊙) = (1.47−0.77+0.64, 0.72−0.38+0.32) lying at a distance DL = 5.07−1.50+0.98 kpc, and the source is a binary composed of a subgiant primary of a late G or an early K spectral type and a main-sequence companion of a K spectral type. The event demonstrates the need for sophisticated modeling of unexplained anomalies if one wants to construct a complete microlensing planet sample.
Key words: gravitational lensing: micro / planets and satellites: detection
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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