1. Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
- Author
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Herald, A, Udalski, A, Bozza, V, Rota, P, Bond, IA, Yee, JC, Sajadian, S, Mroz, P, Poleski, R, Skowron, J, Szymanski, MK, Soszynski, I, Pietrukowicz, P, Kozlowski, S, Ulaczyk, K, Rybicki, KA, Iwanek, P, Wrona, M, Gromadzki, M, Abe, F, Barry, R, Bennett, DP, 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, NJ, Satoh, Y, Sumi, T, Suzuki, D, Silva, SI, Toda, T, Tristram, PJ, Vandorou, A, Yama, H, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Gould, A, Henderson, CB, Johnson, S, Shvartzvald, Y, Zhu, W, Dominik, M, Hundertmark, M, Jorgensen, UG, Longa-Pena, P, Skottfelt, J, Tregloan-Reed, J, Bach-Moller, 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, RA, Tsapras, Y, Christie, GW, Cooper, T, de Almeida, L, Jr, DNJ-D, Green, J, Han, C, Hennerley, S, Marmont, A, McCormick, J, Monard, LAG, Natusch, T, Pogge, R, Collaboration, OGLE, Collaboration, MOA, Team, S, Consortium, M, Collaboration, LCOFUN, European Commission, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
- Subjects
GRAVITATIONAL LENS ,FOS: Physical sciences ,CHEMICAL EVOLUTION ,Astrophysics::Cosmology and Extragalactic Astrophysics ,GALACTIC BULGE ,Q1 ,general [binaries] ,QB Astronomy ,Astrophysics::Solar and Stellar Astrophysics ,PHOTOMETRY ,low-mass [stars] ,QC ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,QB ,Earth and Planetary Astrophysics (astro-ph.EP) ,OPTICAL DEPTH ,Astronomy and Astrophysics ,3rd-DAS ,PLANET CANDIDATE ,Astrophysics - Astrophysics of Galaxies ,DIFFERENCE IMAGE-ANALYSIS ,SPITZER ,low mass [Stars] ,QC Physics ,Astrophysics - Solar and Stellar Astrophysics ,GIANT PLANETS ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,DISCOVERY ,micro [gravitational lensing] ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,brown dwarfs - 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 $M_1 = 0.149 \pm 0.010M_\odot$ and a brown dwarf with mass $M_2 = 0.0463 \pm 0.0031M_\odot$, at a projected separation of $a_\perp = 0.585$ 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., Comment: 13 pages, 6 figures
- Published
- 2022