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Precision measurement of a brown dwarf mass in a binary system in the microlensing event. OGLE-2019-BLG-0033/MOA-2019-BLG-035

Herald, A. and Udalski, A. and Bozza, V. and Rota, P. and Bond, I. A. and Yee, J. C. and Sajadian, S. and Mróz, P. and Poleski, R. and Skowron, J. and Szymanski, M. K. and Soszyński, I. and Pietrukowicz, P. and Kozłowski, S. and Ulaczyk, K. and Rybicki, K. A. and Iwanek, P. and Wrona, M. and Gromadzki, M. and Abe, F. and Barry, R. and Bennett, D. P. and Bhattacharya, A. and Fukui, A. and Fujii, H. and Hirao, Y. and Itow, Y. and Kirikawa, R. and Kondo, I. and Koshimoto, N. and Matsubara, Y. and Matsumoto, S. and Miyazaki, S. and Muraki, Y. and Olmschenk, G. and Ranc, C. and Okamura, A. and Rattenbury, N. J. and Satoh, Y. and Sumi, T. and Suzuki, D. and Ishitani Silva, S. and Toda, T. and Tristram, P. J. and Vandorou, A. and Yamamoto, H. and Beichman, C. A. and Bryden, G. and Calchi Novati, S. and Carey, S. and Gaudi, B. S. and Gould, A. and Henderson, C. B. and Johnson, S. and Shvartzvald, Y. and Zhu, W. and Dominik, M. and Hundertmark, M. and Jørgensen, U. G. and Longa-Peña, P. and Skottfelt, J. and Tregloan-Reed, J. and Bach-Møller, N. and Burgdorf, M. and D’Ago, G. and Haikala, L. and Hitchcock, J. and Khalouei, E. and Peixinho, N. and Rahvar, S. and Snodgrass, C. and Southworth, J. and Spyratos, P. and Zang, W. and Yang, H. and Mao, S. and Bachelet, E. and Maoz, D. and Street, R. A. and Tsapras, Y. and Christie, G. W. and Cooper, T. and de Almeida, L. and do Nascimento, J.-D. and Green, J. and Han, C. and Hennerley, S. and Marmont, A. and McCormick, J. and Monard, L. A. G. and Natusch, T. and 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 and Astrophysics, 663 . Art. No. A100. ISSN 0004-6361. doi:10.1051/0004-6361/202243490.

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Context. Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up. Aims. Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here, we present an analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is caused by 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 the parallax, source radius, and orbital motion of the binary lens. Results. Following an accurate modeling process, we found that the lens is composed of a red dwarf with a mass of M₁ = 0.149 ± 0.010 M_⊙ and a brown dwarf with a mass of M₂ = 0.0463 ± 0.0031 M_⊙ 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. A percent-level precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become more common in the future thanks to the Roman space telescope.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Udalski, A.0000-0001-5207-5619
Bozza, V.0000-0003-4590-0136
Yee, J. C.0000-0001-9481-7123
Mróz, P.0000-0001-7016-1692
Poleski, R.0000-0002-9245-6368
Skowron, J.0000-0002-2335-1730
Szymanski, M. K.0000-0002-0548-8995
Soszyński, I.0000-0002-7777-0842
Pietrukowicz, P.0000-0002-2339-5899
Kozłowski, S.0000-0003-4084-880X
Ulaczyk, K.0000-0001-6364-408X
Rybicki, K. A.0000-0002-9326-9329
Iwanek, P.0000-0002-6212-7221
Wrona, M.0000-0002-3051-274X
Gromadzki, M.0000-0002-1650-1518
Bennett, D. P.0000-0001-8043-8413
Ranc, C.0000-0003-2388-4534
Rattenbury, N. J.0000-0001-5069-319X
Ishitani Silva, S.0000-0003-2267-1246
Yamamoto, H.0000-0001-6919-9570
Beichman, C. A.0000-0002-5627-5471
Bryden, G.0000-0001-5966-837X
Calchi Novati, S.0000-0002-7669-1069
Carey, S.0000-0002-0221-6871
Gaudi, B. S.0000-0003-0395-9869
Henderson, C. B.0000-0001-8877-9060
Johnson, S.0000-0001-9487-8583
Shvartzvald, Y.0000-0003-1525-5041
Dominik, M.0000-0002-3202-0343
Bach-Møller, N.0000-0002-8799-0080
Burgdorf, M.0000-0002-5854-4217
Southworth, J.0000-0002-3807-3198
Bachelet, E.0000-0002-6578-5078
Maoz, D.0000-0002-6579-0483
Street, R. A.0000-0001-6279-0552
Tsapras, Y.0000-0001-8411-351X
Pogge, R.0000-0003-1435-3053
Alternate Title:Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
Additional Information:© ESO 2022. Received: 7 March 2022 Accepted: 3 April 2022. 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 J.C.Y. was supported by JPL grant 1571564. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www., processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work uses observations made at the Observatorio do Pico dos Dias/LNA (Brazil). The lightcurves are only available at the CDS via anonymous ftp to ( or via
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)JSPS24253004
Japan Society for the Promotion of Science (JSPS)JSPS26247023
Japan Society for the Promotion of Science (JSPS)JSPS23340064
Japan Society for the Promotion of Science (JSPS)JSPS15H00781
Japan Society for the Promotion of Science (JSPS)JP16H06287
Japan Society for the Promotion of Science (JSPS)17H02871
Japan Society for the Promotion of Science (JSPS)19KK0082
Marsden Fund of the Royal Society of New ZealandMFP-MAU1901
European Research Council (ERC)860470
Novo Nordisk FoundationNNF19OC0057374
National Natural Science Foundation of China12133005
TAP member institutesUNSPECIFIED
Alexander von Humboldt FoundationUNSPECIFIED
National Research Foundation of Korea2020R1A4A2002885
National Research Foundation of Korea2019R1A2C2085965
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:gravitational lensing: micro / binaries: general / brown dwarfs / stars: low-mass
Record Number:CaltechAUTHORS:20220721-8768000
Persistent URL:
Official Citation:Precision measurement of a brown dwarf mass in a binary system in the microlensing event - OGLE-2019-BLG-0033/MOA-2019-BLG-035 A. Herald, A. Udalski, V. Bozza, P. Rota, I. A. Bond, J. C. Yee, S. Sajadian, P. Mróz, R. Poleski, J. Skowron, M. K. Szymański, I. Soszyński, P. Pietrukowicz, S. Kozłowski, K. Ulaczyk, K. A. Rybicki, P. Iwanek, M. Wrona, M. Gromadzki, (The OGLE collaboration), F. Abe, R. Barry, D. P. Bennett, A. Bhattacharya, A. Fukui, H. Fujii, Y. Hirao, Y. Itow, R. Kirikawa, I. Kondo, N. Koshimoto, Y. Matsubara, S. Matsumoto, S. Miyazaki, Y. Muraki, G. Olmschenk, C. Ranc, A. Okamura, N. J. Rattenbury, Y. Satoh, T. Sumi, D. Suzuki, S. Ishitani Silva, T. Toda, P. J. Tristram, A. Vandorou, H. Yama, (The MOA collaboration), C. A. Beichman, G. Bryden, S. Calchi Novati, S. Carey, B. S. Gaudi, A. Gould, C. B. Henderson, S. Johnson, Y. Shvartzvald, W. Zhu, (The Spitzer team), M. Dominik, M. Hundertmark, U. G. Jørgensen, P. Longa-Peña, J. Skottfelt, J. Tregloan-Reed, N. Bach-Møller, M. Burgdorf, G. D’Ago, L. Haikala, J. Hitchcock, E. Khalouei, N. Peixinho, S. Rahvar, C. Snodgrass, J. Southworth, P. Spyratos, (The MiNDSTEp consortium), W. Zang, H. Yang, S. Mao, E. Bachelet, D. Maoz, R. A. Street, Y. Tsapras, G. W. Christie, T. Cooper, L. de Almeida, J.-D. do Nascimento, J. Green, C. Han, S. Hennerley, A. Marmont, J. McCormick, L. A. G. Monard, T. Natusch, R. Pogge and (The LCO & μFUN collaboration) A&A, 663 (2022) A100 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115742
Deposited By: George Porter
Deposited On:22 Jul 2022 19:49
Last Modified:08 Aug 2022 20:46

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