Issue |
A&A
Volume 675, July 2023
|
|
---|---|---|
Article Number | A36 | |
Number of page(s) | 9 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202346596 | |
Published online | 30 June 2023 |
KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal
1
Department of Physics, Chungbuk National University,
Cheongju
28644, Republic of Korea
e-mail: cheongho@astroph.chungbuk.ac.kr
2
Korea Astronomy and Space Science Institute,
Daejon
34055, Republic of Korea
3
Korea University of Science and Technology, Korea, (UST),
217 Gajeong-ro, Yuseong-gu,
Daejeon
34113, Republic of Korea
4
Institute of Natural and Mathematical Science, Massey University,
Auckland
0745, New Zealand
5
Max-Planck-Institute for Astronomy,
Königstuhl 17,
69117
Heidelberg, Germany
6
Department of Astronomy, Ohio State University,
140 W. 18th Ave.,
Columbus, OH
43210, USA
7
Center for Astrophysics | Harvard & Smithsonian,
60 Garden St.,
Cambridge, MA
02138, USA
8
University of Canterbury, Department of Physics and Astronomy,
Private Bag 4800,
Christchurch
8020, New Zealand
9
Department of Particle Physics and Astrophysics, Weizmann Institute of Science,
Rehovot
76100, Israel
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
Institute for Space-Earth Environmental Research, Nagoya University,
Nagoya
464-8601, Japan
13
Code 667, NASA Goddard Space Flight Center,
Greenbelt, MD
20771, USA
14
Department of Astronomy, University of Maryland,
College Park, MD
20742, USA
15
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku,
Tokyo
113-0033, Japan
16
Instituto de Astrofísica de Canarias,
Vía Láctea s/n,
38205
La Laguna, Tenerife, Spain
17
Department of Earth and Space Science, Graduate School of Science, Osaka University,
Toyonaka, Osaka
560-0043, Japan
18
Department of Physics, The Catholic University of America,
Washington, DC
20064, USA
19
Department of Astronomy, Graduate School of Science, The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku,
Tokyo
113-0033, Japan
20
Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris,
98 bis bd Arago,
75014
Paris, France
21
Department of Physics, University of Auckland,
Private Bag 92019,
Auckland, New Zealand
22
University of Canterbury Mt. John Observatory,
PO Box 56,
Lake Tekapo
8770, New Zealand
Received:
5
April
2023
Accepted:
23
May
2023
Aims. Recently, there have been reports of various types of degeneracies in the interpretation of planetary signals induced by planetary caustics. In this work we check whether such degeneracies persist in the case of well-covered signals by analyzing the lensing event KMT-2021-BLG-1150, the light curve of which exhibits a densely and continuously covered short-term anomaly.
Methods. In order to identify degenerate solutions, we thoroughly investigated the parameter space by conducting dense grid searches for the lensing parameters. We then checked the severity of the degeneracy among the identified solutions.
Results. We identify a pair of planetary solutions resulting from the well-known inner-outer degeneracy, and find that interpreting the anomaly is not subject to any degeneracy other than the inner-outer degeneracy. The measured parameters of the planet separation (normalized to the Einstein radius) and mass ratio between the lens components are (s, q)in ~ (1.297, 1.10 × 10−3) for the inner solution and (s, q)out ~ (1.242, 1.15 × 10−3) for the outer solution. According to a Bayesian estimation, the lens is a planetary system consisting of a planet with a mass Mp = 0.88−0.36+0.38 Mj and its host with a mass Mh = 0.73−0.30+0.32 M⊙ lying toward the Galactic center at a distance DL = 3.8−1.2+1.3 kpc. By conducting analyses using mock data sets prepared to mimic those obtained with data gaps and under various observational cadences, we find that gaps in data can result in various degenerate solutions, while the observational cadence does not pose a serious degeneracy problem as long as the anomaly feature can be delineated.
Key words: planets and satellites: detection / gravitational lensing: micro
© 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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