August
2012
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2012ApJ...755...91S
Authors
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Shin, I. -G.
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Han, C.
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Choi, J. -Y.
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Udalski, A.
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Sumi, T.
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Gould, A.
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Bozza, V.
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Dominik, M.
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Fouqué, P.
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Horne, K.
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Szymański, M. K.
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Kubiak, M.
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Soszyński, I.
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Pietrzyński, G.
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Poleski, R.
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Ulaczyk, K.
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Pietrukowicz, P.
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Kozłowski, S.
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Skowron, J.
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Wyrzykowski, Ł.
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OGLE Collaboration
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Abe, F.
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Bennett, D. P.
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Bond, I. A.
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Botzler, C. S.
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Chote, P.
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Freeman, M.
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Fukui, A.
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Furusawa, K.
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Itow, Y.
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Kobara, S.
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Ling, C. H.
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Masuda, K.
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Matsubara, Y.
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Miyake, N.
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Muraki, Y.
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Ohmori, K.
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Ohnishi, K.
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Rattenbury, N. J.
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Saito, To.
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Sullivan, D. J.
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Suzuki, D.
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Suzuki, K.
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Sweatman, W. L.
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Takino, S.
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Tristram, P. J.
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Wada, K.
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Yock, P. C. M.
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MOA Collaboration
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Bramich, D. M.
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Snodgrass, C.
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Steele, I. A.
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Street, R. A.
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Tsapras, Y.
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RoboNet Collaboration
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Alsubai, K. A.
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Browne, P.
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Burgdorf, M. J.
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Calchi Novati, S.
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Dodds, P.
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Dreizler, S.
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Fang, X. -S.
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Grundahl, F.
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Gu, C. -H.
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Hardis, S.
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Harpsøe, K.
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Hinse, T. C.
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Hornstrup, A.
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Hundertmark, M.
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Jessen-Hansen, J.
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Jørgensen, U. G.
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Kains, N.
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Kerins, E.
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Liebig, C.
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Lund, M.
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Lunkkvist, M.
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Mancini, L.
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Mathiasen, M.
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Penny, M. T.
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Rahvar, S.
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Ricci, D.
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Scarpetta, G.
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Skottfelt, J.
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Southworth, J.
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Surdej, J.
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Tregloan-Reed, J.
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Wambsganss, J.
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Wertz, O.
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MiNDSTEp Consortium
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Almeida, L. A.
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Batista, V.
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Christie, G.
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DePoy, D. L.
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Dong, Subo
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Gaudi, B. S.
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Henderson, C.
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Jablonski, F.
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Lee, C. -U.
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McCormick, J.
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McGregor, D.
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Moorhouse, D.
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Natusch, T.
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Ngan, H.
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Park, S. -Y.
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Pogge, R. W.
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Tan, T. -G.
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Thornley, G.
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Yee, J. C.
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μFUN Collaboration
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Albrow, M. D.
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Bachelet, E.
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Beaulieu, J. -P.
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Brillant, S.
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Cassan, A.
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Cole, A. A.
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Corrales, E.
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Coutures, C.
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Dieters, S.
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Dominis Prester, D.
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Donatowicz, J.
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Greenhill, J.
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Kubas, D.
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Marquette, J. -B.
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Menzies, J. W.
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Sahu, K. C.
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Zub, M.
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PLANET Collaboration
Abstract
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Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 M ⊙ and 0.39 M ⊙ for MOA-2011-BLG-090 and 0.57 M ⊙ and 0.17 M ⊙ for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future.
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