OGLE-2018-BLG-1185b : a low-mass microlensing planet orbiting a low-mass dwarf
Abstract
We report the analysis of planetary microlensing event OGLE-2018-BLG-1185, which was observed by a large number of ground-based telescopes and by the Spitzer Space Telescope. The ground-based lightcurve indicates a low planet-host star mass ratio of q = (6.9 ± 0.2) x 10-5, which is near the peak of the wide-orbit exoplanet mass-ratio distribution. We estimate the host star and planet masses with a Bayesian analysis using the measured angular Einstein radius under the assumption that stars of all masses have an equal probability to host this planet. The flux variation observed by Spitzer was marginal, but still places a constraint on the microlens parallax. Imposing a conservative constraint that this flux variation should be ΔfSpz < 4 instrumental flux units indicates a host mass of Mhost = 0.37 +0.35-0.21 M⊙ and a planet mass of mp = 8.4+7.9-4.7 M⊕. A Bayesian analysis including the full parallax constraint from Spitzer suggests smaller host star and planet masses of Mhost = 0.091+0.064-0.018 M⊙ and mp = 2.1+1.5-0.4 M⊕, respectively. Future high-resolution imaging observations with HST or ELTs could distinguish between these two scenarios and help to reveal the planetary system properties in more detail.
Citation
Kondo , I , Yee , J C , Bennett , D P , Sumi , T , Koshimoto , N , Bond , I A , Gould , A , Udalski , A , Shvartzvald , Y , Jung , Y K , Zang , W , Bozza , V , Bachelet , E , Hundertmark , M P G , Rattenbury , N J , Abe , F , Barry , R , Bhattacharya , A , Donachie , M , Fukui , A , Fujii , H , Hirao , Y , Ishitani Silva , S , Itow , Y , Kirikawa , R , Li , M C A , Matsubara , Y , Miyazaki , S , Muraki , Y , Olmschenk , G , Ranc , C , Satoh , Y , Shoji , H , Suzuki , D , Tanaka , Y , Tristram , P J , Yamawaki , T , Yonehara , A , Mróz , P , Poleski , R , Skowron , J , Szymański , M K , Soszyński , I , Kozłowski , S , Pietrukowicz , P , Ulaczyk , K , Rybicki , K A , Iwanek , P , Wrona , M , Albrow , M D , Chung , S-J , Han , C , Hwang , K-H , Kim , H-W , Shin , I-G , Cha , S-M , Kim , D-J , Kim , S-L , Lee , C-U , Lee , D-J , Lee , Y , Park , B-G , Pogge , R W , Ryu , Y-H , Beichman , C A , Bryden , G , Calchi Novati , S , Carey , S , Gaudi , B S , Henderson , C B , Zhu , W , Maoz , D , Penny , M T , Dominik , M , Jørgensen , U G , Longa-Peña , P , Peixinho , N , Sajadian , S , Skottfelt , J , Snodgrass , C , Tregloan-Reed , J , Burgdorf , M J , Campbell-White , J , Dib , S , Fujii , Y I , Hinse , T C , Khalouei , E , Rahvar , S , Rabus , M , Southworth , J , Tsapras , Y , Street , R A , Bramich , D M , Cassan , A , Horne , K , Wambsganss , J , Mao , S & Saha , A 2021 , ' OGLE-2018-BLG-1185b : a low-mass microlensing planet orbiting a low-mass dwarf ' , Astronomical Journal , vol. 162 , no. 2 , 77 . https://doi.org/10.3847/1538-3881/ac00ba
Publication
Astronomical Journal
Status
Peer reviewed
ISSN
0004-6256Type
Journal article
Rights
Copyright © 2021 American Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.3847/1538-3881/ac00ba.
Description
Funding: Work by I.K. was supported by JSPS KAKENHI grant No.20J20633. Work by J.C.Y. was supported by Jet Propulsion Laboratory grant 1571564. Work by D.P.B., A.B., and C.R. was supported by NASA through grant NASA-80NSSC18K0274. T.S. acknowledges financial support from the JSPS (JSPS23103002, JSPS24253004, and JSPS26247023). Work by N.K. is supported by JSPS KAKENHI grant No. JP18J00897. A.S. is a University of Auckland doctoral scholar. Y.T. acknowledges the support of DFG priority program SPP 1992 Exploring the Diversity of Extrasolar Planets (WA 1047/11-1). T.C.H. acknowledges financial support from the National Research Foundation (No. 2019R1I1A1A01059609). U.G.J. acknowledges support from H2020-MSCA-ITN-2019, grant No. 860470 (CHAMELEON), and the NovoNordisk Foundation grant No. NNF19OC0057374. W.Z. and S.M. acknowledge support by the National Science Foundation of China (grant Nos. 11821303 and 11761131004). Work by C.H. was supported by grants of the National Research Foundation of Korea (2020R1A4A2002885 and 2019R1A2C2085965). Funding for B.S.G. was provided by NASA grant NNG16PJ32C and the Thomas Jefferson Chair for Discovery and Space Exploration.Collections
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