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OGLE-2018-BLG-0532Lb: Cold Neptune with Possible Jovian Sibling

Ryu, Yoon-Hyun and Udalski, Andrzej and Yee, Jennifer C. and Penny, Matthew T. and Zang, Weicheng and Albrow, Michael D. and Chung, Sun-Ju and Gould, Andrew and Han, Cheongho and Hwang, Kyu-Ha and Jung, Youn Kil and Shin, In-Gu and Shvartzvald, Yossi 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. and Mróz, Przemek and Szymański, Michał K. and Skowron, Jan and Poleski, Radek and Soszyński, Igor and Pietrukowicz, Paweł and Kozłowski, Szymon and Ulaczyk, Krzysztof and Rybicki, Krzysztof A. and Iwanek, Patryk and Wrona, Marcin and Mao, Shude and Fouque, Pascal and Zhu, Wei and Wang, Tianshu (2020) OGLE-2018-BLG-0532Lb: Cold Neptune with Possible Jovian Sibling. Astronomical Journal, 160 (4). Art. No. 183. ISSN 1538-3881.

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We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio q = M_(planet)/M_(host) ≃ 1 x 10⁻⁴. Although there are no obvious systematic residuals to this double-lens/single-source (2L1S) fit, we find that χ² can be significantly improved by adding either a third lens (3L1S, Δχ² = 81) or second source (2L2S, Δχ² = 77) to the lens-source geometry. After thorough investigation, we conclude that we cannot decisively distinguish between these two scenarios and therefore focus on the robustly detected planet. However, given the possible presence of a second planet, we investigate to what degree and with what probability such additional planets may affect seemingly single-planet light curves. Our best estimates for the properties of the lens star and the secure planet are a host mass M ~ 0.25 M_⊙, system distance D_L ~ 1 kpc, and planet mass m_(p,1) = 8 M_⊕ with projected separation a_(1,⟂) = 1.4 au. However, there is a relatively bright I = 18.6 (and also relatively blue) star projected within < 50 mas of the lens, and if future high-resolution images show that this is coincident with the lens, then it is possible that it is the lens, in which case, the lens would be both more massive and more distant than the best-estimated values above.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ryu, Yoon-Hyun0000-0001-9823-2907
Udalski, Andrzej0000-0001-5207-5619
Yee, Jennifer C.0000-0001-9481-7123
Penny, Matthew T.0000-0001-7506-5640
Zang, Weicheng0000-0001-6000-3463
Albrow, Michael D.0000-0003-3316-4012
Chung, Sun-Ju0000-0001-6285-4528
Han, Cheongho0000-0002-2641-9964
Hwang, Kyu-Ha0000-0002-9241-4117
Jung, Youn Kil0000-0002-0314-6000
Shin, In-Gu0000-0002-4355-9838
Shvartzvald, Yossi0000-0003-1525-5041
Cha, Sang-Mok0000-0002-7511-2950
Kim, Hyoun-Woo0000-0001-8263-1006
Kim, Seung-Lee0000-0003-0562-5643
Lee, Chung-Uk0000-0003-0043-3925
Lee, Yongseok0000-0001-7594-8072
Park, Byeong-Gon0000-0002-6982-7722
Pogge, Richard W.0000-0003-1435-3053
Mróz, Przemek0000-0001-7016-1692
Szymański, Michał K.0000-0002-0548-8995
Skowron, Jan0000-0002-2335-1730
Soszyński, Igor0000-0002-7777-0842
Pietrukowicz, Paweł0000-0002-2339-5899
Kozłowski, Szymon0000-0003-4084-880X
Ulaczyk, Krzysztof0000-0001-6364-408X
Rybicki, Krzysztof A.0000-0002-9326-9329
Iwanek, Patryk0000-0002-6212-7221
Wrona, Marcin0000-0002-3051-274X
Mao, Shude0000-0001-8317-2788
Zhu, Wei0000-0003-4027-4711
Additional Information:© 2020. The American Astronomical Society. Received 2019 April 15; revised 2020 July 24; accepted 2020 July 27; published 2020 September 25. Work by A.G. was supported by AST-1516842 from the US NSF. I.G.S. and A.G. were supported by JPL grant 1500811. A.G. received support from the European Research Council under the European Union's Seventh Framework Programme (FP 7) ERC grant Agreement No. [321035] Work by C.H. was supported by the grant (2017R1A4A1015178) of National Research Foundation of Korea. 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. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. This research used data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences (the Strategic Priority Research Program "The Emergence of Cosmological Structures" grant No. XDB09000000), and the Special Fund for Astronomy from the Ministry of Finance. This work was partly supported by the National Science Foundation of China (grant No. 11333003, 11390372 to S.M.). Partly based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the CanadaFranceHawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de lUnivers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. M.T.P. was supported by NASA grants NNX14AF63G and NNG16PJ32C, as well as the Thomas Jefferson Chair for Discovery and Space Exploration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Research Council (ERC)321035
National Research Foundation of Korea2017R1A4A1015178
National Science Centre (Poland)2014/14/A/ST9/00121
National Astronomical Observatories, Chinese Academy of Sciences (NAOC)UNSPECIFIED
Chinese Academy of SciencesXDB09000000
Ministry of Finance (China)UNSPECIFIED
National Natural Science Foundation of China11333003
National Natural Science Foundation of China11390372
Thomas Jefferson Chair for Discovery and Space ExplorationUNSPECIFIED
Subject Keywords:Gravitational microlensing
Issue or Number:4
Classification Code:Unified Astronomy Thesaurus concepts: Gravitational microlensing (672)
Record Number:CaltechAUTHORS:20200925-091914987
Persistent URL:
Official Citation:Yoon-Hyun Ryu et al 2020 AJ 160 183
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105542
Deposited By: George Porter
Deposited On:25 Sep 2020 17:32
Last Modified:25 Sep 2020 17:32

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