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A Free-floating or Wide-orbit Planet in the Microlensing Event OGLE-2019-BLG-0551

Mróz, Przemek and Poleski, Radosław and Han, Cheongho and Udalski, Andrzej and Gould, Andrew and Szymański, Michał K. and Soszyński, Igor and Pietrukowicz, Paweł and Kozłowski, Szymon and Skowron, Jan and Ulaczyk, Krzysztof and Gromadzki, Mariusz and Rybicki, Krzysztof and Iwanek, Patryk and Wrona, Marcin and Albrow, Michael D. and Chung, Sun-Ju and Hwang, Kyu-Ha and Ryu, Yoon-Hyun and Jung, Youn Kil and Shin, In-Gu and Shvartzvald, Yossi and Yee, Jennifer C. and Zang, Weicheng and Cha, Sang-Mok and Kim, Dong-Jin and Kim, Hyoun-Woo and Kim, Seung-Lee and Lee, Chung-Uk and Lee, Dong-Joo and Lee, Yongseok and Park, Byeong-Gon and Pogge, Richard W. (2020) A Free-floating or Wide-orbit Planet in the Microlensing Event OGLE-2019-BLG-0551. Astronomical Journal, 159 (6). Art. No. 262. ISSN 1538-3881. doi:10.3847/1538-3881/ab8aeb.

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High-cadence observations of the Galactic bulge by the microlensing surveys led to the discovery of a handful of extremely short-timescale microlensing events that can be attributed to free-floating or wide-orbit planets. Here, we report the discovery of another strong free-floating planet candidate, which was found from the analysis of the gravitational microlensing event OGLE-2019-BLG-0551. The light curve of the event is characterized by a very short duration (≾3 days) and a very small amplitude (≾0.1 mag). From modeling of the light curve, we find that the Einstein timescale, t_E = 0.381 ± 0.017 day, is much shorter, and the angular Einstein radius, θ_E = 4.35 ± 0.34 μas, is much smaller than those of typical lensing events produced by stellar-mass lenses (t_E ~ 20 days, θ_E ~ 0.3 mas), indicating that the lens is very likely to be a planetary-mass object. We conduct an extensive search for possible signatures of a companion star in the light curve of the event, finding no significant evidence for the putative host star. For the first time, we also demonstrate that the angular Einstein radius of the lens does not depend on blending in the low-magnification events with strong finite source effects.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Mróz, Przemek0000-0001-7016-1692
Poleski, Radosław0000-0002-9245-6368
Han, Cheongho0000-0002-2641-9964
Udalski, Andrzej0000-0001-5207-5619
Szymański, Michał K.0000-0002-0548-8995
Soszyński, Igor0000-0002-7777-0842
Pietrukowicz, Paweł0000-0002-2339-5899
Kozłowski, Szymon0000-0003-4084-880X
Skowron, Jan0000-0002-2335-1730
Ulaczyk, Krzysztof0000-0001-6364-408X
Gromadzki, Mariusz0000-0002-1650-1518
Rybicki, Krzysztof0000-0002-9326-9329
Iwanek, Patryk0000-0002-6212-7221
Wrona, Marcin0000-0002-3051-274X
Albrow, Michael D.0000-0003-3316-4012
Chung, Sun-Ju0000-0001-6285-4528
Hwang, Kyu-Ha0000-0002-9241-4117
Ryu, Yoon-Hyun0000-0001-9823-2907
Jung, Youn Kil0000-0002-0314-6000
Shin, In-Gu0000-0002-4355-9838
Shvartzvald, Yossi0000-0003-1525-5041
Yee, Jennifer C.0000-0001-9481-7123
Zang, Weicheng0000-0001-6000-3463
Pogge, Richard W.0000-0003-1435-3053
Additional Information:© 2020 The American Astronomical Society. Received 2020 March 2; revised 2020 April 16; accepted 2020 April 17; published 2020 May 14. P.M. acknowledges support from the National Science Center, Poland (grant ETIUDA 2018/28/T/ST9/00096). R.P. was supported by Polish National Agency for Academic Exchange via Polish Returns 2019 grant. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. Work by A.G. was supported by AST-1516842 from the US NSF and by JPL grant 1500811. Work by C.H. was supported by the grants of National Research Foundation of Korea (2017R1A4A1015178 and 2019R1A2C2085965). This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI) and the data were obtained at three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia.
Funding AgencyGrant Number
National Science Centre (Poland)ETIUDA 2018/28/T/ST9/00096
Narodowa Agencja Wymiany AkademickiejUNSPECIFIED
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
National Research Foundation of Korea2017R1A4A1015178
National Research Foundation of Korea2019R1A2C2085965
Subject Keywords:Gravitational microlensing ; Free floating planets ; Gravitational microlensing exoplanet detection ; Finite-source photometric effect
Issue or Number:6
Classification Code:Unified Astronomy Thesaurus concepts: Gravitational microlensing (672); Free floating planets (549); Gravitational microlensing exoplanet detection (2147); Finite-source photometric effect (2142)
Record Number:CaltechAUTHORS:20200514-132550914
Persistent URL:
Official Citation:Przemek Mróz et al 2020 AJ 159 262
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103203
Deposited By: Tony Diaz
Deposited On:14 May 2020 21:04
Last Modified:16 Nov 2021 18:19

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