Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
Abstract
Context. Brown dwarfs are poorly understood transition objects between stars and planets, with several competing mechanisms having been proposed for their formation. Mass measurements are generally difficult for isolated objects but also for brown dwarfs orbiting low-mass stars, which are often too faint for spectroscopic follow-up. Aims. Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here we present the analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is due to a binary system composed of a brown dwarf orbiting a red dwarf. Methods. Thanks to extensive ground observations and the availability of space observations from Spitzer, it has been possible to obtain accurate estimates of all microlensing parameters, including parallax, source radius and orbital motion of the binary lens. Results. After accurate modeling, we find that the lens is composed of a red dwarf with mass M1 = 0.149 ± 0.010M⊙ and a brown dwarf with mass M2 = 0.0463 ± 0.0031M⊙, at a projected separation of a ⊥ = 0.585 au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. Percent precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become common with the Roman space telescope.
Citation
Herald , A , Udalski , A , Bozza , V , Rota , P , Bond , I A , Yee , J C , Sajadian , S , Mroz , P , Poleski , R , Skowron , J , Szymanski , M K , Soszynski , I , Pietrukowicz , P , Kozlowski , S , Ulaczyk , K , Rybicki , K A , Iwanek , P , Wrona , M , Gromadzki , M , Abe , F , Barry , R , Bennett , D P , Bhattacharya , A , Fukui , A , Fujii , H , Hirao , Y , Itow , Y , Kirikawa , R , Kondo , I , Koshimoto , N , Matsubara , Y , Matsumoto , S , Miyazaki , S , Muraki , Y , Olmschenk , G , Ranc , C , Okamura , A , Rattenbury , N J , Satoh , Y , Sumi , T , Suzuki , D , Ishitani Silva , S , Toda , T , Tristram , P J , Vandorou , A , Yama , H , Beichman , C A , Bryden , G , Calchi Novati , S , Carey , S , Gaudi , B S , Gould , A , Henderson , C B , Johnson , S , Shvartzvald , Y , Zhu , W , Dominik , M , Hundertmark , M , Jorgensen , U G , Longa-Pena , P , Skottfelt , J , Tregloan-Reed , J , Bach-Møller , N , Burgdorf , M , D'Ago , G , Haikala , L , Hitchcock , J , Khalouei , E , Peixinho , N , Rahvar , S , Snodgrass , C , Southworth , J , Spyratos , P , Zang , W , Yang , H , Mao , S , Bachelet , E , Maoz , D , Street , R A , Tsapras , Y , Christie , G W , Cooper , T , de Almeida , L , do Nascimento , J-D J , Green , J , Han , C , Hennerley , S , Marmont , A , McCormick , J , Monard , L A G , Natusch , T & Pogge , R 2022 , ' Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035 ' , Astronomy & Astrophysics , vol. 633 , A100 . https://doi.org/10.1051/0004-6361/202243490
Publication
Astronomy & Astrophysics
Status
Peer reviewed
ISSN
0004-6361Type
Journal article
Rights
Copyright © ESO 2022. 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/10.1051/0004-6361/202243490.
Description
Funding: The MOA project is supported by JSPS KAK-ENHI Grant Number JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, JP16H06287,17H02871 and 19KK0082 and a Royal Society of New Zealand Marsden Grant MFP-MAU1901. U.G.J. acknowledges funding from the European Union H2020-MSCA-ITN-2019 under Grant no. 860470 (CHAMELEON) and from the Novo Nordisk Foundation Interdisciplinary Synergy Program grant no. NNF19OC0057374. W.Zang, W.Zhu, H.Y. and S.M. acknowledge support by the National Science Foundation of China (Grant No. 12133005). This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the TAP member institutes. Work by C.R. was supported by a Research Fellowship of the Alexander von Humboldt Foundation. Work by C.H. was supported by the grants of National Research Foundation of Korea (2020R1A4A2002885 and 2019R1A2C2085965). Work by JCY was supported by JPL grant 1571564.Collections
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